Thermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III)—a single-source precursor for antimony sulfide thin films

Journal of Thermal Analysis and Calorimetry

https://doi.org/10.1007/s10973-021-10885-1

Thermal decomposition

of tris(O‑ethyldithiocarbonato)‑antimony(III)—a single‑source

precursor for antimony sulfde thin flms

Jako S. Eensalu¹· Kaia Tõnsuaadu²· Jasper Adamson³· Ilona Oja Acik¹· Malle Krunks¹

Received: 31 July 2020 / Accepted: 2 May 2021

Abstract

Thermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III) (1), a precursor for Sb₂S₃thin flms synthesized from

an acidifed aqueous solution of SbCl₃and KS₂COCH₂CH₃, was monitored by simultaneous thermogravimetry, diferential

thermal analysis and evolved gas analysis via mass spectroscopy (TG/DTA-EGA-MS) measurements in dynamic Ar, and

synthetic air atmospheres. 1 was identifed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic reso-

nance (NMR) measurements, and quantifed by NMR and elemental analysis. Solid intermediates and fnal decomposition

products of 1 prepared in both atmospheres were determined by X-ray difraction (XRD), Raman spectroscopy, and FTIR. 1

is a complex compound, where Sb is coordinated by three ethyldithiocarbonate ligands via the S atoms. The thermal degra-

dation of 1 in Ar consists of three mass loss steps, and four mass loss steps in synthetic air. The total mass losses are 100%

at 800 °C in Ar, and 66.8% at 600 °C in synthetic air, where the fnal product is Sb₂O₄. 1 melts at 85 °C, and decomposes at

90–170 °C into mainly Sb₂S₃, as confrmed by Raman, and an impurity phase consisting mostly of CSO²₂⁻ligands. The solid-

phase mineralizes fully at ≈240 °C, which permits Sb₂S₃to crystallize at around 250 °C in both atmospheres. The gaseous

species evolved include CS₂, C₂H₅OH, CO, CO₂, COS, H₂O, SO₂, and minor quantities of C₂H₅SH, (C₂H₅)₂S, (C₂H₅)₂O,

and (S₂COCH₂CH₃)₂. The thermal decomposition mechanism of 1 is described with chemical reactions based on EGA-MS

and solid intermediate decomposition product analysis.

Keywords Antimony ethyl xanthate · Thermal degradation · Evolved gas analysis · Antimony sulfde · Decomposition

mechanism

Introduction

Antimony sulfde (Sb₂S₃) is a material naturally suitable

for application as the absorber layer in thin flm solar cells.

The crustal abundance and price of Sb (0.2 ppm; $8.6 kg⁻¹),

and S (340 ppm; $0.05 kg⁻¹), which form the nontoxic

* Jako S. Eensalu

jako.eensalu@taltech.ee

Sb₂S₃, attest to its long-term economic viability as a stra-

* Malle Krunks

tegic resource [1–3]. The anisotropic Sb₂S₃has a bandgap

malle.krunks@taltech.ee

of ≈1.7 eV, a high absorption coefcient of 1⋅10⁵cm⁻¹at

1

450 nm, a melting point of 550 °C, and is stable toward

moisture, UV, and oxidation in air below 150 °C, being

etched only by concentrated acid [4–7]. A bandgap of 1.7 eV

makes Sb₂S₃a prime candidate for application as the top

cell absorber in tandem solar cells [8, 9], and as the thinner

than 200 nm absorber in IR inactiv e semitransparent solar

cells [10, 11].

Laboratory of Thin Film Chemical Technologies,

Department of Materials and Environmental Technology,

Tallinn University of Technology, Ehitajate tee 5,

19086 Tallinn, Estonia

2

3

Laboratory of Inorganic Materials, Department of Materials

and Environmental Technology, Tallinn University

of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia

Laboratory of Chemical Physics, National Institute

of Chemical Physics and Biophysics, Akadeemia tee 23,

12618 Tallinn, Estonia

Sb₂S₃thin flms have been fabricated from colloidal or

metal–organic precursors by a number of solution-based

Vol.:(0123456789)

1 3

J. S. Eensalu et al.

chemical methods, e.g., chemical bath (CBD) [12–14 ],

atomic layer deposition (ALD) [15–17 ], spin-coating [18,

19], spray pyrolysis [11, 20–22 ], and by physical meth-

ods, e.g., thermal evapor ation (TE) from inorganic targets

[23], mainly for application as absorber in thin flm solar

cells. The highest power conversion efciency achieved for

planar Sb₂S₃thin flm solar cell is 6.6% by spin-coating a

metal–organic complex of Sb, followed by annealing and

Cs-doping [19], whereas the top power conversion efciency

of Sb₂S₃solar cells is 7.5% [24]. Mass production of Sb₂S₃

solar cells with consistent power conversion efficiency

requires use of simple and cost-efective methods, e.g.,

spray pyrolysis, as other methods are likely too expensive

(vacuum, inert gas, specialty reagents for ALD, TE), too

time consuming and waste-generating (CBD), or too small-

scale (spin-coating) [25].

decade as a single-source precursor to fabricate Sb₂S₃pow-

ders for various applications, or to make porous layers for

use as the absorber in solar cells by solution-based chemical

methods, e.g., solvothermal, or spin-coating coupled with

post-deposition annealing at 160–240 °C [33, 39, 45].

A comprehensive thermal decomposition s tudy of SbEX,

where TG/DTA is coupled with evolved gas analysis and

intermediate solid decomposition product analysis, has not

been published. Sporadic studies of TG curves of SbEX have

been published with contradictory and vague statements

regarding t he tem perature required to produce phase pure

Sb₂S₃[32, 33, 39, 45]. Therefore, a comparative study of the

TG/DTA-EG A-MS of SbEX in inert and oxidizing atmos-

phere is required to determine its suitability for depositing

phase pure Sb₂S₃thin flms for application in semitranspar-

ent, bifacial, and as the top cell absorber in tandem solar

cells, in addition to other semiconductor applications.

Aiming to determine the viability of SbEX as a single-

source precursor for depositing Sb₂S₃thin flms by ultra-

sonic spray pyrolysis, we investigate the thermal decompo-

sition of SbEX in inert and synthetic air atmosphere in this

study by TG/DTA-EGA-MS coupled with analysis of the

solid intermediate decomposition products of SbEX, and

describe the mechanism of thermal decomposition of SbEX.

In order to fabricate Sb₂S₃thin flms from organometal-

lic precursors, it is crucial to understand their decomposi-

tion mechanisms in oxidizing and inert atmosphere. Our

laboratory has experience in analysis of formation of CuS,

In₂S₃, CuInS₂, ZnS, and SnS thin flms by employing TG/

DTA-EGA for thiourea-based precursors to estimate the

appr opriate deposition conditions for spray pyrolysis in air

[26–31]. The resulting thin flms contained C and Cl impu-

rities, except in case of Sb₂S₃, where uniform thin flms of

Sb₂S₃, free of C and Cl to detectable limits, were deposited

at 210 °C by spray pyrolysis, wherein a liquid-phase reac-

tion occurred due to a favorably low melting point of the

precursors [22]. As lowering the deposition and annealing

temperature of Sb₂S₃thin flms is critical for application

as the ≈1.7 eV top absorber in tandem solar cells, the pro-

cessing temperature must be decreased further. Moreover,

lower processing temperature and shorter processing time

would decrease the energy budget, ergo, the cost of produc-

ing Sb₂S₃thin flm-based solar cells and other devices, and

increase the selection of usable substrates.

Experimental

Synthesis

Potassium ethyldithiocarbonate (potassium ethyl xan-

thate, KEX) (>97 mass%, Acros) and antimony(III)chlo-

ride (SbCl₃) (99 mass%, Sigma-Aldrich), deionized water

(18.2 MΩcm⁻¹), and HCl (≥37 vol%, Sigma-Aldrich) were

employed for the synthesis of the precursor for thermal

analysis. All chemicals were used as-bought without fur-

ther purifcation. The precursor for thermal analysis was

synthesized according to the literature [40], with some

modifcations.

Metal xanthates, i.e., alkoxy- or aryldithiocarbonates,

tend to decompose at low temperatures (100–250 °C) [32,

33], which is suitable to deposit metal chalcogenide thin

f lms onto polymer substrates for fexible applications, and

to fabricate the top cell for tandem solar cells. However, the

decomposition mechanism and temperature of each xanthate

depend signifcantly on the combination of cation [34], and

ligand [33], meaning that TG/DTA-EGA could be of use.

Xanthates, e.g., potassium ethyl xanthate (KS₂COCH₂CH₃,

KEX) were discovered by W. C. Zeise in 1822 [4]. Since

then, xanthates and related organometallic compounds are

being used in ore fotation, in organic chemistry, in analytical

chemistry, in biochemistry, in coordination chemistry, and in

materials science to fabricate metal chalcogenide powders

and layers, e.g., ZnS, NiS, Fe₂S₃, Cu₂S, PbS, As₂S₃, Sb₂S₃,

Bi₂S₃, and lead-free perovskites [4, 32, 34–44]. Antimony

ethyl xanthate (SbEX) has risen to pr ominence in the last

The precursor was synthesized at room temperature by

pouring 375 mM of KEX to 200 mL of 125 mM SbCl₃,

acidifed beforehand with HCl to retain SbCl₃, while stir-

ring. A bright yellow substance started precipitating imme-

diately upon mixing. The solution was stirred for 60 min.

The precipitate was rinsed with deionized water, diethyl

ether (99.5 vol%, Sigma-Aldrich), and acetone (99.8 vol%,

Merck), then recrystallized from acetone and rinsed with

water at 83% yield. This product, named 1 going forward,

was used for further analysis.

1 3

Thermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III)—a single-source…

Elemental analysis

Thermal analysis

The elemental composition of 1 was analyzed by energy-

dispersive X-ray spectroscopy (EDX) on a Zeiss Ultra 55

FEG HR-SEM setup equipped with a Bruker ESPRIT 1.8

system. The atomic ratio of S/Sb was found to be 5.7 0.1,

which is 93–97% of the expected stoichiometric atomic ratio

of S to Sb of 6.0 in SbEX.

The simultaneous TG/DTA/EGA-MS measurement of 1

was performed in a Setaram LabSys EVO apparatus, using

a heating rate of 10 °C min⁻¹, purge gas (Ar or 80% Ar,

20% O₂–synthetic air) with a fow rate of 60 mL min⁻¹

,

sample mass 14.2 mg (in Ar), and 13.5 mg (in synthetic

air) in open Al₂O₃crucible. The gaseous species were

guided into a ThermoStar GSD320 quadrupole mass spec-

trometer through a heated capillary tube kept at 180 °C.

Data were collected in multiple ion detection mode (MID)

monitoring 21 channels between m/z = 1–89. Collection

time was 1 s for each channel. EGA-MS fgures were gen-

erated with OriginLab software.

Nuclear magnetic resonance analysis

The nuclear magnetic resonance (NMR) analysis was carried

out on a 800 MHz Bruker Avance III setup connected with

a 18.8 T magnet/ 54 mm heat opening diameter at 25 °C.

Samples of 1 were weighed, and dissolved in CDCl₃(99.8

vol%, Eurisotop) for 1D qualitative ¹H, 1D quantitative ¹³C,

2D homonuclear correlation spectroscopy (COSY), hetero-

nuclear single-quantum correlation spectroscopy (HSQC),

and heteronuclear multiple-bond correlation spectroscopy

The evolved gases were identifed based on their MS

reference spectra available in the public domain spectral

library of NIST [47]. Reaction schemes were generated

with ACD ChemSketch freeware.

1

(HMBC) NMR. For 1D quantitative H analysis, 1 and

2-Propanol (99.9 vol%, Sigma-Aldrich) were weighed in a

fxed molar ratio on a microbalance after antistatic screen-

ing, and co-dissolved in CD₃OD (MeOD, 99.8 vol%, Euri-

sotop). Chemical shifts in ppm were calibrated relative to

CDCl₃and MeOD. The residual mass of 1 in the weigh-

ing tray was subtracted before quantifcation. NMR data

were analyzed, and fgures were generated using Mestrelab

MNova software.

Intermediate decomposition product preparation

Intermediate decomposition products of 1 were prepared

in inert atmosphere in laboratory test as follows: after

purging the quartz tube inside the two-zone tube furnace

to 1⋅10^–3mbar at room temperature, 99.999% N₂fow of

60 mL min⁻¹, and heating rate of 10 °C min⁻¹were used,

while retaining the ceramic crucible at 170 °C, 270 °C,

400 °C, or 730 °C for 10 min before cooling in ambient

to ≈40 °C and withdrawing. Intermediate decomposition

products of 1 in air were prepared in laboratory test at

170 °C, 270 °C, and 480 °C by inserting 1 into a preheated

mufe furnace, and retaining the specifed temperature in

the crucible for 10 min before withdrawing. At 600 °C, the

residue from TG/DTA in synthetic air was used.

Vibrational analysis

The FTIR spectra of KEX and 1 were measured on a FTIR

setup (Perkin Elmer GX 2000), 400–4000 cm⁻¹, 4 cm⁻¹

resolution, 32 scans, by the KBr pellet method, using the

FTIR spectrum of the KBr pellet as background. 1.0 mass%

of sample per 200 mg of KBr, pre-dried in air at 150 °C for

1 h, was pressed into a 13 mm-diameter pellet after grinding

the mixture with a corundum pestle and mortar.

For FTIR analysis of the products of the frst decom-

position step, intermediate decomposition products of 1

were prepared in inert atmosphere in the same two-zone

tube furnace as follows: after purging to 1⋅10^–3mbar at

room temperature, 99.999% N₂fow of 30 mL min⁻¹, and

heating rate of 5 °C min⁻¹were used, while retaining the

crucible at 115 °C, or 160 °C for 3 min before cooling in

ambient to ≈40 °C and withdrawing. For FTIR analysis

of the frst decomposition step, intermediate decomposi-

tion products of 1 in air were prepared as follows: 1 was

inserted into a preheated mufe furnace and heated in a

semi-closed crucible, to prevent the solid from surging

out, at the specifed temperature for 3 min before with-

drawal, and immediately cooled in a cold water bath to

room temperature.

The FTIR spectra of 1, and its intermediate decomposi-

tion products prepared at 115 °C, and at 160 °C in fowing

N₂, and air were measured on a Bruker Alpha FTIR setup,

equipped with a diamond anvil in absorptance mode, 24

scans, resolution 4 cm⁻¹.

In addition, Raman spectra of 1 and its intermediate solid

decomposition products were measured on a micro-Raman

setup (Horiba LabRam 800, 15 μW µm⁻², 532 nm He–Ne, Ø

5 μm), calibrated with 546.1 nm Hg line. Raman data were

analyzed with Fityk software [46]. FTIR and Raman fgures

were generated with OriginLab software.

1 3

J. S. Eensalu et al.

strong band at 1230 cm⁻¹in 1. C–O–C stretching modes

shifting to higher wavenumbers likely points to a shorten-

ing of C–O–C bonds in the ligand. Weaker bands appear-

ing at 3000–2870 cm⁻¹, 1468 cm⁻¹, 1448 cm⁻¹, 1075 cm⁻¹

and 813 cm⁻¹attributed to CH₃and CH₂stretching and

bending modes did not shift considerably, revealing that

the interaction between the ethyl group and the cation (K,

Sb) is weak, as expected. Therefore, the ethyl group is

the farthest, and the CS₂group is probably the closest to

Sb, connected to each other by the C–O–C bridge. The

wide band positioned at 3650–3300 cm⁻¹in both KEX and

1 is attributed to adsorbed H₂O.

Structural analysis

The phase composition of 1, its intermediate and final

decomposition products were analyzed with a powder XRD

(Rigaku Ultima IV, Si strip detector D/teX Ultra), Cu K_α1

λ

1.5406 Å, θ-2θ mode, 5°min⁻¹, step 0.02°, 40 kV, 40 mA.

XRD data were analyzed using Rigaku PDXL 2 software.

Figures were generated with OriginLab software.

Results and discussion

The Raman spectrum of 1 is shown in Fig. S1. So far, the

Raman spectrum of SbEX is unindexed, though 35 Raman

active optical modes in the range of 50–3000 cm⁻¹were

observed in the Raman spectrum of 1. The most intense

Raman bands of 1 are centered at 91, 167, 232, 339, 406,

439, 665, 845, 998, and 1029 cm⁻¹. Raman band centers

of 1, with possible assignments from compounds similar

to SbEX [43, 48, 50], are listed in Table S2. Raman bands

attributed to onl y 1 were found above the limit of detection.

The crystal structure of SbEX is rhombohedral, space

Identifcation of 1

The FTIR spectra of potassium ethyl xanthate

(KS₂COC₂H₅– KEX) and antimony ethyl xanthate

(Sb(S₂COC₂H₅)₃– SbEX) have been published before,

being only presented in this study to identify and demon-

strate the purity of KEX and 1. FTIR spectra of KEX and

1, as measured by the KBr technique, are shown in Fig. 1.

The list of possible assignments of FTIR bands of KEX

and 1, based on the literature [36, 38, 41–43, 48, 49], is

presented in Table S1 in the electr onic Suppor ting File.

According to FTIR, the spectra of KEX and 1 were

similar, although bands had shifted in the range of

1300 cm⁻¹–1000 cm⁻¹in 1 vs KEX, showing that the com-

plex with Sb seems to have formed. The C = S stretching

modes shifted from 1006 cm⁻¹and 1050 cm⁻¹in KEX to

1001 cm⁻¹, and 1024 cm⁻¹in 1, indicating the formation

of longer C-S bonds as a result of the stronger electron pull

toward Sb in the Sb-S bond than in the K-S bond due to Sb

being more electronegative than K. The symmetric C–O–C

stretching (1103 cm⁻¹, 1118 cm⁻¹) in KEX, shifted to

1112 cm⁻¹, and 1135 cm⁻¹in 1. The asymmetric C–O–C

stretching (1158 cm⁻¹, 1173 cm⁻¹) in KEX, merged into a

group R 3, a = 10.13 Å, α = 103°30´, six units in the unit

̅

cell, and each Sb atom is known to be surrounded by three

S atoms at 2.52 Å, and another three at 3.00 Å, which alto-

gether form a distor ted octahedron, extending into the planar

S₂C-O group [51, 52]. The XRD pattern of rhombohedral

SbEX is available in the CSD database under SBXANT, and

the XRD pattern of 1 is presented only to confrm its identity

as SbEX (Fig. S2, numeric data in Table S3). According to

XRD, additional phases above the limit of detection were

not found in 1.

The 1D NMR analysis results are presented in Table 1.

Minor traces of acetone and ethanol were found in 1. Evi-

1

dently, the acquired H and ¹³C NMR data correspond to

Fig. 1 FTIR spectra of potas-

KEX

sium ethyl xanthate (KEX) and

1 recorded with 4 cm⁻¹resolu-

tion in KBr pellet

1

ρ(C-H)

δ(O-C-C)

ν(C-S)

ν(O-C-S)

δ(C-H)

ν(O-H)

ν_s(C=S)

ν_as(C=S)

ν (C-O-C)

ν(C-H)

CH₂& CH₃

ν_as(C-O-C)

s

4000 3600 3200 28001600 1400 1200 1000

Wavenumber/cm^–1

500

450

400

1 3

Thermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III)—a single-source…

Table 1 ¹H and ¹³C spectral data of 1 in comparison to the literature [33, 53]

Compound

¹H / ppm

¹³C / ppm

Integral of ¹H

Functional group

Found in 1

Literature

Ref

Found in 1

Literature

Ref

1

2-PrOH

CDCl₃

CH₃COCH₃

2-PrOH

7.26, s

2.17, s

1.20, d

4.01, sept

1.47, t

4.64, q

–

7.26

2.17

1.22

4.04

1.40

4.55

[53]

[33]

77.16

–

25.48

64.53

14.00

72.17

222.60

77.16

30.92

25.14

64.50

12.40

71.00

221.40

[53]

[33]

–

3.00

2.00

–

CHCl₃

-CH₃

–CH₃

–CH-

–CH₃

–CH₂-

–O–C–S₂

0.01

6.26

1.00

4.18

2.15^a

–

1

^aThe CH₂functional group was used to calculate the purity of 1 with respect to the known amount of 2-PrOH. There was overlap between the

signals for the CH₃functional group of 2-PrOH and the CH₃functional group of 1, which prevented accurate integration of these proton peaks

Table 2 COSY, HSQC and HMBC spectral data of 1

can be derived as CH₃–CH₂–O–CS₂–. The quantitative 1D

¹H NMR experiment showed that the molar ratio of CH₃

functional groups in 1 to 2-PrOH is 1.42 (expected 1.50,

i.e.,, 3/2). As ≈5 mol% of 1 is Sb₂S₃, then the molar ratio

of CH₃in the EX ligand to Sb³⁺is close to the expected

stoichiometric value of 3.

Method

COSY

¹H / ppm

¹³C / ppm

Functional groups^a

1.43

4.60

1.46

4.64

1.46

4.64

4.65

1.48

–

–CH₂–CH₃

HSQC

14.04

72.16

14.04

72.16

222.60

–CH₃

–CH₂–

–CH₂–CH₃

S₂–C–O–CH₂–

In summary, FTIR showed that the vibrational modes

of 1 correspond to only SbEX, and the main bands had

shifted in comparison to KEX, indicating the formation of

a complex with a more electronegative metal. XRD showed

that only rhombohedral SbEX was detected in 1. Raman

showed that bands attributed to only 1 were detected. Fur-

ther investigation by NMR showed that there are approxi-

mately three ligands per molecule of 1 with the structure

of -S₂COCH₂CH₃, i.e., the EX ligand. According to quan-

HBMC

^aHMBC correlated nuclei are in bold

relevant values in the literature [33, 53], thereby comple-

menting the FTIR data in identifcation of 1.

1

titative H NMR, 1 contains approximately 95 mol% of

According to quantitative H of CH₃, the analyte con-

SbEX. The slight defciency of S was also observed by EDX

(95 2 mol% of theoretical value). The remaining 5 mol%

was identifed as amorphous Sb₂S₃by Raman. Therefore, 1

has been identifed as 95 mol% Sb(S₂COCH₂CH₃)₃– SbEX,

and 5 mol% of amorphous Sb₂S₃.

tained the equivalent of 95 mol% of (EX)₃versus 2-PrOH

(Table 1). The remaining 5 mol% of 1 precipitated in the

NMR test tube. According to XRD, the red precipitate was

amorphous, as no refections were observed. The Raman

spectrum of the precipitate contained a single broad band,

stretching from 200–360 cm⁻¹, and c entered at 290 cm⁻¹,

characteristic of amorphous Sb₂S₃[21, 22]. Thus, the results

of quantitative NMR, XRD, and Raman support the obser-

vations made in EDX analysis of 1 regarding its slight def-

ciency of sulfur (S/Sb of 1.42) vs stoichiometric composition

of S/Sb of 1.50. Indeed, it is known that SbEX can change

from light yellow to dark yellow, then to orange by decom-

posing over time to amorphous Sb₂S₃[36].

Thermal analysis

According to TG curves of 1 (Fig. 2), the thermal decompo-

sition occurred in three mass loss steps in argon in the range

of 90–800 °C, whereas in synthetic air, four mass loss steps

were observed in the range of 90–590 °C. The endothermic

step at 85 °C in both atmospheres is the melting point of 1,

because in laboratory test, a melting point of 1 of 77 1 °C

was measured on slow heating in air (cf. 75 °C in [32],

68–70 °C in [33]), wherein a viscous adhesive clear yellow

liquid formed. The frst mass loss step was endothermic in

both atmospheres, as DTA peaked at 140 °C, preceding the

DTG maximum at 135 °C. Similarly, in both atmospheres,

two consecutive exothermic efects occurred in the second

mass loss step at 235 °C and 250 °C in argon, and 235 °C

and 245 °C in synthetic air, together with a DTG maximum

Based on the liquid NMR COSY analysis (Table 2), 1

contains mutually J-bonded CH₃and CH₂groups. HSQC

analysis revealed that the two observed peaks at (¹H 1.46;

¹³C 14.04) and (¹H 4.64; ¹³C 72.16) correlate with one

another, proving that the CH₃and CH₂functional groups

are directly bonded in 1. According to HMBC analysis,

three cross-peaks appeared (Table 2; Fig. S3). Thus, the CH₂

functional group is bonded to both the CH₃, and the OCS₂

functional group and the sequence of functional groups in 1

1 3

J. S. Eensalu et al.

Fig. 2 TG, DTG, and DTA

curves of 1 in a argon, fow

60 mL min⁻¹, heating rate

10°min⁻¹, initial mass 11.6 mg,

and b synthetic air, fow

60 mL min⁻¹, heating rate

10°min⁻¹, initial mass 13.9 mg,

as measured in situ by the

online coupled TG/DTA-MS

system

(a)

100

(b)

TG

I

80% Argon, 20% O₂

350

Argon

100

I

DTG

365

570

90

80

70

60

50

40

30

235

240

80

60

40

20

0

235

250

135

550

DTA

570

II

135

DTA

245

III

235

II

140

85

III

IV

140

85

0

200

400

600

800

0

200

400

600

Temperature/°C

positioned at 240 °C in argon, and 235 °C in synthetic air,

respectively.

step in synthetic air at 570 °C simultaneously with the DTG

peak at 570 °C.

Mass was constant in argon between 250 and 590 °C,

although a sharp endothermic efect occurred at 550 °C. A

broad endothermic efect occurred throughout the third mass

loss step in argon beginning at 600 °C. An intense exother-

mic efect appeared in the third mass loss step in synthetic

air, peaking at 365 °C, trailing the DTG peak at 350 °C. A

weaker exothermic efect occurred in the fourth mass loss

The frst mass loss step in both atmospheres was in the

range of 90–170 °C with mass losses of 66.3% in argon,

and 61.1% in synthetic air. The second mass loss step was

in the range of 170 °C-255°C in argon, and 170 °C-250°C in

synthetic air, with mass loss of 2.1% in both cases. The third

mass loss step started in argon at 590 °C, proceeding until

810 °C, where all of the remaining mass was lost. The mass

Table 3 Decomposition steps, mass losses, temperatures of DTA and

DTG peaks, evolved gases, and detected crystalline phases of 1. TG/

DTA-MS data recorded using a heating rate of 10 °C min⁻¹in argon,

and synthetic air atmosphere with open Al₂O₃crucible on a Setaram

LabSys EVO instrument

Atmosphere Step Tem-

Mass loss at the end

of the decomposition

step /%

DTA peak temp./°C DTG

max

Evolved gases from

MS^a

Crystalline phases at the

end of the decomposition

step (XRD data), ICDD

PDF No

perature

range/°C

temp./°C

Ar

1

2

90–170

170–255

66.3

68.4

140 endo

235 exo, 250 exo

135

CS₂, EtOH, CO, CO₂, None

COS

240

–

Sb₂S₃(stibnite, 01–075-

H₂O, EtSH, SO₂

4012)

3

590–800

100

–

Sb₂S₃, Sb (05–0562) at

730 °C

Final 800 °C

100

61.1

63.2

no solid residue

Ar+O₂

1

2

90–170

170–250

140 endo

235 exo, 245 exo

135

235

CS₂, EtOH, CO, CO₂, None

COS

Sb₂S₃

H₂O, EtSH, SO₂

3

250–495

65.8

365 exo

570 exo

350

570

SO₂

Sb₂O₄(cervantite,

01–074-8714)

Sb₂O₄(600 °C)

Sb₂O₄

4

495–590

66.8

Final 600 °C

^aMajor gases in bold

1 3

Thermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III)—a single-source…

loss of 1 in argon above 590 °C is the result of incongruent

evaporation of liquid Sb₂S₃per the Sb-S phase diagram [5,

7, 54], as the product collected at 730 °C consisted of cry s-

talline Sb₂S₃and metallic Sb according to XRD (Table 3).

In synthetic air, the third mass loss step was in the range

of 250–495 °C with mass loss of 2.6%. The fourth mass loss

step in synthetic air was in the range of 495–590 °C with

mass loss of 1.0%. Final mass loss was 100% in argon at

800 °C, and 66.8% in synthetic air at 600 °C. The theoretical

mass loss in argon at 600 °C is 65.0% (experimental 68.3%),

assuming pure Sb₂S₃phase. The theoretical mass loss in air

is 68.3%, as the fnal product in synthetic air was Sb₂O₄. The

fnal mass loss of 1 in synthetic air was lower than calculated

due to presence of Sb₂S₃in 1.

Evolved gas analysis in argon and synthetic air

atmosphere by online EGA‑MS

The evolution curves of gases as ion currents of character-

istic mass fragments of the identifed gaseous species vs

temperature evolved from 1 in argon, and in synthetic air in

comparison, as recorded by online EGA-MS, are shown in

Fig. 3. Peak centers and assignments of all measured EGA-

MS channels are listed in Table S4.

According to EGA-MS in argon, the evolution of gases

started at 50 °C with the evolution of adsorbed moisture

as water (H₂O) with characteristic ion fragment of m/z 18,

peaking at 82 °C. Evolution of water below 100 °C was

not detected in synthetic air likely because the sample was

purged for an extended period of time vs the sample in argon

before commencing the EGA-MS run.

(a)

(b)

(c)

8E – 09

4E – 09

m/z 31

m/z 76

CS₂

m/z 28

137

143

EtOH

CO & C₂H₄

CH₂OH⁺& OCH⁺₃

CO⁺& C₂H⁺₄

CS₂

143

Ar

Ar + O₂

Ar

Ar + O₂

Ar

Ar + O₂

2E – 09

4E – 09

0E + 00

4E – 09

240

0E

+ 00

0E

+ 00

50

100 150 200 250 300

Temperature/°C

50

100 150 200 250 300

Temperature/°C

50

100 150 200 250 300

Temperature/°C

(d)

(e)

(f)

4E – 09

2E – 09

0E + 00

4E – 09

137

m/z 18

H₂O

H₂O⁺

Ar

m/z 60

COS

m/z 44

CO₂& COS & CS₂

CO⁺₂& CS⁺

OCS⁺

Ar

Ar + O₂

2E – 09

138

135

82

240

0E

+

00

0E + 00

50

100 150 200 250 300

Temperature/°C

50

100 150 200 250 300

Temperature/°C

50

100 150 200 250 300

Temperature/°C

(g)

(h)

(i)

m/z 64

SO₂

m/z 62

EtSH & Et₂S

C₂H₅SH⁺

m/z 32

Ar

Ar + O₂

165

148

m/z 75

Et₂S

C₂H₅SCH⁺₂

Ar

4E – 10

2E – 08

1E – 08

SO⁺₂

360

1E – 09

5E – 10

0E + 00

Ar

Ar + O₂

Ar

Ar + O₂

131

245

238

Ar + O₂

2E – 10

138

135

241

135

240

575

0E

+ 00

0E

+ 00

100 200 300 400 500 600

Temperature/°C

50

100 150 200 250 300

Temperature/°C

50 100 150 200 250 300 350

Temperature/°C

Fig. 3 Gas evolution profles of CS₂a, EtOH b, CO and C₂H₂c,

CO₂, CS₂, and COS d, COS e, H₂O f, SO₂g, EtSH and Et₂S h, and

unknown m/z 32 i, represented by their characteristic mass spec-

troscopic ion fragments, from 1 in argon (in black or green), fow

60 mL min⁻¹, heating rate 10°min⁻¹, initial mass 11.6 mg, and

in synthetic air (in red or violet), fow 60 mL min⁻¹, heating rate

10°min⁻¹, initial mass 13.9 mg, as measured by in situ online coupled

TG/DTA-EGA-MS system. (Color fgure online)

1 3

J. S. Eensalu et al.

The frst decomposition step (90–170 °C) began simi-

larly in argon and synthetic air with the evolution of sev-

eral gases: carbon disulfde (CS₂, m/z 76, Fig. 3a), ethanol

(EtOH, m/z 31, Fig. 3b), carbon monoxide (CO, m/z 28,

Fig. 3c; possibly partially attributable to C₂H₄), carbon

dioxide (CO₂, m/z 44, Fig. 3d; partially attributable to

CS⁺from CS₂and COS), carbonyl sulfde (COS, m/z 60,

Fig. 3e), water (m/z 18, Fig. 3f), and sulfur dioxide (SO₂,

m/z 64, Fig. 3g), Substantial evolution of gaseous frag-

ments corresponding to the methyl group (CH₃, m/z 15,

Fig. S4a), and the ethyl or formyl group (C₂H₅or CHO,

m/z 29, Fig. S4b) was also detected. Evolution of some

minor gases was also detected, e.g., ethanethiol (EtSH,

m/z 62, Fig. 3h), diethyl sulfde (Et₂S, m/z 75, Fig. 3h),

diethyl ether (Et₂O, m/z 74, Fig. S4c) and dixanthogen

((EX₂), m/z 89, Fig. S4d).

than in the frst and second step, peaking at 360 °C. In the

fourth decomposition step in synthetic air (495–590 °C),

SO₂evolved from 530 to 590 °C, peaking at 575 °C. The

evolution curve of SO₂in synthetic air closely resembles

the DTA curve (Fig. 2b), and follows the DTG peak posi-

tions in the temperature range of 200–600 °C, indicating

that the exothermic DTA efects in that temperature range

in synthetic air are directly related to the evolution of SO₂.

Discussion of thermal analysis results

To establish the basis for describing the decomposition

mechanism of 1, laboratory tests were made to investigate

the phase composition of the solid intermediate decompo-

sition products of 1 at various temperatures in inert and air

atmosphere. These intermediate decomposition products of

1 were characterized by FTIR, XRD, and Raman to deter-

mine the phase composition at various stages of the decom-

position process.

In argon, the evolution curve of the tentatively unas-

signed m/z 32 corresponded to CS₂, COS, and SO₂, with a

maximum at 135 °C. Thus, in argon, m/z 32 is attributed

to the S⁺fragment of CS₂, COS, and SO₂, and possibly to

molecular MeOH. The evolution curve of m/z 32 in syn-

thetic air is a conundrum, because after 131 °C the curve

is unlike any of the monitored m/z channels, its intensity

looming over other gases by an order of magnitude without

mass loss nor any DTA efects. This strange phenomenon

was observed in experiments run in synthetic air with

Al₂O₃and Pt crucible (not shown), where the shape and

intensity of the evolution curve were similarly anomalous.

In synthetic air, m/z 32 could correspond to S⁺(COS, CS₂,

H₂S, S₈), or MeOH, but comparison to other m/z curves

disproved this possibility. Therefore, m/z 32 in synthetic

air remained unresolved in this study.

The slight diference in FTIR spectra of some band posi-

tions of 1 in respect to measurements by KBr method is

attributed to difer ences in instrument setup and measure-

ment mode (Fig. 1 vs. Fig. 4). Tentative FTIR assignments in

the f ollo wing discussion ar e based on the literature [36, 38,

41–43, 48–50, 55–57]. According to FTIR, the vibrational

modes of t he inter mediate decomposition product prepared

at 115 °C in N₂are nearly identical to those of 1 (Fig. 4a).

By 160 °C, the FTIR spectrum has changed signifi-

cantly, as bands attributed to CH₃and CH₂stretching

(2800–3000 cm⁻¹), scissoring (1386 cm⁻¹, 1443 cm⁻¹

,

1468 cm⁻¹), twisting (1075 cm⁻¹), and rocking (813 cm⁻¹)

modes have disappeared, indicating that the ethyl group

(CH₃CH₂–) has been cleaved, and has exited into the gas

The second decomposition step (170–255 °C in argon,

170–250 °C in synthetic air) proceeded with the evolution

of CS₂, EtOH, CO, CO₂, COS, H₂O, SO₂, EtSH, Et₂S,

Et₂O, and (EX)₂in a proportionally smaller quantity,

refecting the ≈30 times smaller mass loss in the second

decomposition step compared to the frst (2.1% vs. 66.3%

in argon; 2.1% vs. 61.1% in synthetic air). In the second

decomposition step in argon, and synthetic air the evo-

lution curves of gases were asymmetric, tailing toward

lower temperatures, peaking at 240 °C. The asymmetric

evolution curve in EGA-MS supports the TG/DTA results

in that two consecutive exothermic processes occur in the

second decomposition step, peaking at 235 °C and 250 °C

in argon, and at 235 °C and 245 °C in synthetic air (Fig. 2).

The evolution of most gaseous species ceased by the end

of the second decomposition step at ≈270 °C, indicating

complete decomposition of organic material. In argon, no

evolution of gases was detected beyond 270 °C, whereas

in synthetic air, only SO₂and m/z 32 continued to evolve.

In the third decomposition step in synthetic air

(250–495 °C), SO₂evolved in a signifcantly larger amount

phase. Furthermore, the O–C–C scissoring (407 cm⁻¹

,

436 cm⁻¹) of the ethyl group has disappeared, in correlation

with EGA-MS results, where evolution of EtOH peaked at

143 °C, and ended by 160–165 °C (Fig. 3b). Adsorbed water

has evolved by 160 °C in N₂, because the broad band (O–H

stretching, 3000–3700 cm⁻¹) is not present in the spectrum

of the solid intermediate (Fig. 4a). Moreover, by 160 °C in

N₂, bands have shifted from 995 cm⁻¹to 967 cm⁻¹(C=S

symmetric stretching; bond elongation), from 1230 cm⁻¹to

1254 cm⁻¹(C–O–C asymmetric stretching; bond shorten-

ing), and from 1682 cm⁻¹to 1643 cm⁻¹(conjugated C=O

stretching; bond elongation) (Fig. 4a). The shift in band

positions and new bands at 870 cm⁻¹(O–C–S stretching),

and 2021 cm⁻¹(S–C=O stretching) likely indicates the for-

mation of a monothiocarbonate ligand (CSO₂²⁻).

The FTIR spectrum of the solid intermediate prepared

at 115 °C in air is similar to the spectra of 1 and the solid

intermediate prepared at 115 °C in N₂, although some

features difer: a C = O stretching band at 1643 cm⁻¹in

air vs 1742 cm⁻¹in N₂, and a more intense band between

1 3

Thermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III)—a single-source…

Fig. 4 FTIR spectra of 1 and

its intermediate decomposition

products prepared in labora-

tory tests in N₂a, and in air

b in the frst decomposition

step at 115 °C and 160 °C, as

measured with diamond anvil in

refectance mode at resolution

of 4 cm⁻¹, 24 scans

(a)

ν_s(C-O-C)

N₂

ν (C=S)

ν_as(C-O-C)

^asν_s(C=S)

δ(O-C-C)

ν(C-H) CH₃& CH₂

δ(C-H)

ν(C-S)

ρ(C-H)

ν(O-H)

ν(C=O)

1

ν_as(C=S)

ν_s(C=S)

ν(S-C=O) ν(C=O)

115 °C

160 °C

ν_as(C-O-C)

ν(O-C-S)

4000

3000

2000

1000

Wavenumber/cm^–1

500

400

(b)

ν_s(C-O-C)

Air

ν (C=S)

ν_as(C-O-C)

^asν_s(C=S)

δ(O-C-C)

ν(C-H) CH₃& CH₂

δ(C-H)

ν(C-S)

ρ(C-H)

ν(O-H)

ν(C=O)

1

115 °C

ν_as(C=S)

ν_as(C-O-C)

ν(S-C=O)

ν_s(C=S)

ν(O-C-S)

160 °C

4000

3000

2000

1000

Wavenumber/cm^–1

500

400

3000–3700 cm⁻¹than in 1 (O–H stretching), showing that

free water has formed during the decomposition of 1 due to

air oxidation of the ethyl group. The FTIR spectrum of the

solid intermediate prepared at 160 °C in air is similar to the

spectrum of the residue prepared at 160 °C in N₂, except a

weak residual of the ethyl group at 2800–3000 cm⁻¹(CH₃,

CH₂stretching) possibly due to insufcient time for decom-

position of 1 in laboratory test. In summary, the intermediate

decomposition products prepared at 160 °C in N₂, and in air

appear to contain one or more ligands composed of C=O,

C–S, O=C–S, O–C–S, and possibly C–O–C fragments, with

traces of ethyl group.

COS, CS₂and EtOH likely form via competing reactions,

where one Sb-S coordination bond is broken, followed by

intramolecular rearrangement of bonds between the alkoxy

and dithiocarbonyl group (Scheme 1, reaction 1 and reaction

2). With rotation of the dithiocarbonyl group, followed by

cleavage of COS that evolves as a gas, Sb(R₁)(R₂)SCH₂CH₃

is produced (Scheme 1, reaction 1a). Without rotation of the

dithiocarbonyl group, CS₂is cleaved, evolving as a gas, and

Sb(R₁)(R₂)OCH₂CH₃(Scheme 1, reaction 2a) is produced.

Reaction 2 and reaction 2a in Scheme 1 is most likely the

main reaction, as this sequence is the most straightforward

and credible source of CS₂–the main evolved gas. Reaction

2a is likely thermodynamically preferred over reaction 1a in

Scheme 1, as rotation of the dithiocarbonyl group, and redis-

tribution of twice as many bonds in reaction 1a vs reaction

2a requires overcoming a higher activation energy barrier.

In Scheme 1, Reaction 1a accounts for COS, and reaction

2a for CS₂. Thus, further reactions are needed to explain

the evolution of CO₂, CO, EtOH, and H₂O. Also, EtSH as a

The main gases CS₂, EtOH, CO, CO₂, COS, and H₂O

co-evolve in the frst decomposition step, thus, the decom-

position of SbEX cannot proceed merely by direct cleavage

of the EX ligand, and must proceed through one or more

parallel reactions. As SbEX is liquid before and during the

decomposition, liquid-phase radical and ionic reactions that

are common for xanthate reactions should occur [35, 37].

1 3

J. S. Eensalu et al.

H₃C

CH₂

S

O

H₃C

CH₂

O

S

H₃C

CH₂

O

R₁

R₂

H₃C

CH₂

S

R₁

R₂

C

R₁

R₂

C

R₁

R₂

1b

CO₂

1c

1a

O

C S

Sb

+

O

C S

Sb

+

Sb

90-170°C

1

R₂

S

CH₂

O

Sb

H₃C

R₁

C

S

90-170°C

2

CH₂

O

S

H₃C

CH₂

O

S

H₃C

CH₂

O

R₁

R₂

H₃C

CH₂

S

R₁

C

R₁

R₂

C

R₁

2b

COS

2c

2a

O

C O

Sb

+

S

C S

+

S

Sb

O Sb

R₂

H

H₃C

CH₂

S

H₃C

CH₂

S

3

5

S

Sb

R₁

O

Sb

+

OH

O

4

S

Sb

R₁

Sb

+

SH

S

R₁

CH₂

S

OEt

CH₂

S

SEt

6

Sb

R₁

S

Sb

R₁

+

R₁

Scheme 1 Proposed decomposition reactions of SbEX occurring in the frst decomposition step. R₁, R₂=EX / EtO / EtS / CSO₂/ CSO₂Et / SH

minor gas probably forms in two reaction steps because of

steric inhibition of interaction between S and CH₃CH₂- in

the EX ligand, as evinced by NMR and EGA-MS results.

Mirroring reaction 1a, CO₂and EtSH could be produced

by reaction 2c in Scheme 1, whereby COS is injected into

Sb(R₁)(R₂)OEt (R = EX / SH / EtO / EtS), followed by

rearrangement of the COS moiety to yield Sb(R₁)(R₂)SEt

and CO₂. Reactions like 1b and 2b in Scheme 1, where the

metal hydroxide, thiol, alkoxide, or mercaptane reacts as

a Lewis base with CS₂, COS, or CO₂anhydride as Lewis

acid, are known to form carbonates, thiocarbonates, and

their alkyl-substituted derivatives [58].

Fig. 5 Raman spectra of 1 and

its intermediate decomposition

products in laboratory tests in a

N₂, fow 60 mL min⁻¹, heating

rate 10°min⁻¹after pre-purging

to 1⋅10^–2mbar, heating time

10 min, and in b air, where 1

was inserted into a preheated

furnace and heated at the

(a)

(b)

Reference Sb₂O₃

Reference Sb₂S₃

Reference Sb₂O₃

Nitrogen

Air

Reference Sb₂S₃

600 °C, Sb₂O₄-cervantite

400 °C, Sb₂S₃

480 °C, Sb₂O₄-cervantite

specifed temperature for 10 min

before withdrawal and cooling

270 °C, Sb₂S₃& Sb₂O₃

170 °C, Sb₂S₃& Sb₂O₃

1

100

200

300

400

500

100

200

300

400

500

Raman shift/cm^–1

1 3

Thermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III)—a single-source…

Considering the sizeable and rapid mass loss in the frst

decomposition step, Sb(EX)₂OEt could degrade further

by decomposition of the remaining EX ligands, followed

by evolution of EtOH, e.g., reaction 3 in Scheme 1, while

retaining enough Sb-S bonds to form Sb₂S₃, as confrmed

by Raman (Fig. 5b), because no intermediate decomposi-

tion products of 1 in inert atmosphere wit h Sb-O bonding

were detected by neither Raman (Fig. 5a) nor XRD (Fig. 6a).

By analogy to reaction 3, the remaining EX lig ands of

Sb(EX)₂SEt could decompose, followed by evolution of

EtSH (e.g., reaction 4 in Scheme 1).

by reaction 2a or reaction 1c in Scheme 1. Reaction 1c in

Scheme 1 is unlikely to contribute signifcantly to the ther-

mal decomposition of 1, because it requires gaseous CO₂

as reactant, which forms in reaction 2c, in turn dependent

on COS produced in reaction 1a. Consequently, reaction 1c

in Scheme 1 has 6 prerequisite reaction steps before it can

occur.

Et₂O and Et₂S are minor byproducts, probably forming

via proton transfer between intermediate neighbor ligands

and subsequent cleavage from Sb, e.g., reaction 4 and reac-

tion 6 in Scheme 1. SO₂as a minor gas likely forms in

argon by hydrolysis of COS or CS₂to H₂S and CO₂or

CO, ending with H₂S oxidizing to SO₂and H₂O [59]. As

the quantity of protons is limited in 1 to the ethyl group in

the EX ligand above 90 °C, the formation of EtOH, EtSH,

and H₂O in argon (and air) requires the formation of an

equivalent quantity of ethylene (C₂H₄) via proton transfer

to supply the protons. Therefore, the EGA-MS of m/z 28

attributed to CO could be in part attributed to the evolu-

tion of C₂H₄in addition to CO, albeit without defnitive

proof, as characteristic m/z of C₂H₄overlap with EtOH

and other evolved gases. C₂H₄could react in air with O₂to

form oxirane (C₂H₄(O)) or acetaldehyde [4], although nei-

ther can be confrmed with EGA-MS due to overlap with

m/z of main gases. Water evolves as a product of various

decomposition and condensation reactions of intermediate

products in the thermal decomposition of SbEX with the

atmosphere having no signifcant efect on its evolution.

Finally, CO could evolve from hydrolysis of CS₂or COS

[59], or via incomplete oxidation of EtOH.

Judging by EGA-MS evolution intensity (Fig. 3), the evo-

lution of EtSH is an order of magnitude smaller compared

to EtOH, meaning the EtS ligand likely undergoes further

reactions, acting as a supply of S for Sb₂S₃, i.e., reaction 5

and reaction 6 in Scheme 1, whereas EtOH evolves directly,

i.e., reaction 3 in Scheme 1. Reactions 3–6 in Scheme 1

should proceed, as the interaction between ligands is not

sterically inhibited, and because the ligands are small, sin-

gle-bonded throughout, and therefore able to rotate around

the axis of the single coordination bond with Sb. Another

possible explanation for the sparse evolution of EtSH could

be that reaction 2b is the rate determining step: frst, because

Sb(R₁)(R₂)OEt is probably consumed mainly in reaction 3

in Scheme 1 to produce EtOH; second, because the insertion

of COS into Sb(R₁)(R₂)OEt is a gas–liquid reaction limited

by the concentration of COS dissolved or dispersed in the

liquid mixture.

The combined intensity of evolving CO, COS and CO₂in

EGA-MS is similar to the intensity of evolving CS₂, which

could indicate that reaction 2b in Scheme 1 is supplied with

COS by reaction 1a or reaction 1c, and with Sb(R₁)(R₂)OEt

The results of this study show that the Chugaev

elimination, which is often used to describe xanthate

Fig. 6 XRD patterns of 1 and

its intermediate decomposition

products in laboratory tests in a

N₂, fow 60 mL min⁻¹, heating

rate 10°min⁻¹after pre-purging

to 1⋅10^–2mbar, heating time

10 min, and in b air, where 1

was inserted into a preheated

furnace and heated at the

(a)

(b)

730 °C

600 °C Sb₂O₄

Nitrogen

Air

Sb₂S₃& ♠ Sb

♠

480 °C Sb₂O₄

& Sb₂O₃

♠

350 °C Sb₂(S₂O₇)₃&

Sb₂S₃& Sb₂O₄

specifed temperature for 10 min

before withdrawal and cooling

270 °C

Sb₂S₃

270 °C Sb₂S₃

170 °C

1

Sb₂S₃

10

Sb₂S₃

10

20

30

/°

40

50

20

30

/°

40

50

2

θ

2

θ

1 3

J. S. Eensalu et al.

decomposition [35, 37], does not apply for 1 at all, because

in it only COS and C₂H₄are formed – neither the dominant

gas in the frst decomposition step of 1 (Fig. 3). Clearly, as

the Chugaev elimination cannot explain the co-evolution

of CS₂, CO, CO₂, H₂O, EtOH, EtSH, Et₂S, and Et₂O in

inert and oxidizing atmospheres, the reaction is not valid.

At the end of the frst decomposition step at 170 °C in

argon, and air, about 3 mass% of the initial mass of organic

species is retained in amorphous Sb₂S₃(Table 3). The solid

intermediate prepared at 170 °C in both N₂and air was

amorphous according to XRD, as seen in Fig. 6. However,

according to Raman (Fig. 5b), a mixture of Sb₂S₃and Sb₂O₃

(senarmontite) had formed in air at 170 °C by direct oxida-

tion of Sb₂S₃. The asymmetric shape of the EGA-MS (Fig. 3)

curves in addition to the two successive exothermic efects

witnessed in DTA (Fig. 2) signifes that either more stable

inorganic or organic ligands, e.g., CSO²₂⁻, EtOCOS⁻, EtS⁻,

EtO⁻, or a separate dispersed phase has formed inside the

amorphous Sb₂S₃phase, as seen from the FTIR spectra of

solid intermediates prepared at 160 °C (Fig. 4). Presumably,

the residual organic species are expelled as the gases seen

in EGA-MS (Fig. 3), followed by crystallization of purifed

Sb₂S₃(Fig. 6 ), as its nucleation is no longer inhibited. Elu-

cidating the precise composition of this residual impurity in

Sb₂S₃, which persists in the solid phase over 100 °C above

the frst decomposition, warrants further investigation.

The second decomposition step occurred in the range

of 170–255 °C in Ar and 170–250 °C in synthetic air,

with a mass loss of 2.1% in both cases, evolution of minor

amount of CS₂, EtOH, CO, CO₂, COS, H₂O, SO₂, EtSH,

Et₂S, Et₂O, and (EX)₂(Fig. 3), and orthorhombic Sb₂S₃was

the fnal solid product in inert atmosphere, and a mixture

of Sb₂S₃and cubic Sb₂O₃in air, as determined by Raman

(Fig. 5b). Based on the FTIR analysis of the solid inter-

mediate products (Fig. 4), antimony monothiocarbonate

(Sb₂(CSO₂)₃), a trace of antimony ethyl monothiocarbonate

(Sb(SOCOCH₂CH₃)₃), and possibly other (thio)carbonyl

ligands persist until 240 °C. According to EGA-MS, trace

quantities of presumed Sb-SEt, Sb-OEt, or Sb-OSCOEt

ligands survive, evolving as EtOH, EtSH, Et₂O, and Et₂S

by 250 °C (Fig. 3, Fig. S4). No FTIR bands were observed

in any residue prepared at or above 270 °C in either atmos-

phere (not shown), meaning that all carbonaceous matter had

mineralized or evolved by that point, in correlation with the

results of EGA-MS (Fig. 3, Fig. S4).

a mixture of Sb₂(S_nO_3n+1)₃(n=1; 2; 3; 4), e.g., Sb₂(S₂O₇)₃,

ICDD 1–070–2198, and Sb₂(SO₄)₂(S₂O₇), 1–083–2537, then

to Sb₂O₃, and fnally to Sb₂O₄with vigorous exothermic

evolution of SO₂. Therefore, the formation of sulfates above

300 °C in the third decomposition step in air initially caused

a slight mass gain that was masked by the net mass loss of

2.6% from the energetic SO₂evolution. The oxidation rate

and oxidation product of Sb₂S₃at 350–500 °C is strongly

dependent on temperature, and particle size [60], which

explains the simultaneous detection of antimony compounds

in progressive stages of oxidation in the residue.

In the fourth decomposition step in synthetic air in the

range of 495–590 °C, the exothermic mass loss at 570 °C

coupled with evolution of SO₂at 575 °C is caused by puri-

fcation of residual sulfate via transition of senarmontite-

Sb₂O₃into valentinite-Sb₂O₃at 570 °C (cf. 570 °C in [5],

581 °C in [54]), followed by oxidation into Sb₂O₄, as seen

by the diference in XRD patterns of residues prepared

at 480 °C (senarmontite-Sb₂O₃& cervantite-Sb₂O₄) and

600 °C (cervantite-Sb₂O₄) in air (Fig. 6b). The intermediate

residue prepared in N₂at 730 °C was composed of Sb₂S₃

and Sb (Fig. 6a). The incongruent evaporation of Sb₂S₃pro-

ceeding above its melting point at 550 °C is complete by

800 °C, which is consistent with results of previous studies

[54], where total mass loss of Sb₂S₃was observed in inert

atmosphere.

Similarly to thiourea–metal chloride complexes that we

used to deposit SnS, ZnS, CuInS₂, In₂S₃, and Sb₂S₃thin

f lms b y spr ay pyrolysis for photovoltaic applications [11,

20–22, 61–64], SbEX appears to be an excellent single-

sour ce pr ecursor for producing phase pure Sb₂S₃thin flms

by spray pyrolysis.

Conclusions

It was shown that, according to FTIR and NMR, 1, syn-

thesized from KEX and SbCl₃in molar ratio of Sb/S

of 1/3, contains a coordination complex, wherein three

-S₂COCH₂CH₃– ethyl xanthate ligands are coordinated to

Sb atom via S atoms. According to elemental analysis and

1

quantitative H NMR, 1 contains approximately 95 mol%

of Sb(S₂COCH₂CH₃)₃, and 5 mol% of amorphous Sb₂S₃, as

identifed by Raman.

The thermal decomposition of 1 consists of three mass loss

steps in argon in the temperature range of 90–800 °C, whereas

in synthetic air, four mass loss steps occurred in the tempera-

ture range of 90–590 °C with mass loss of 100% and 66.8%,

respectively. The frst and second thermal decomposition steps

proceed similarly in argon and synthetic air in the temperature

range of 90–170 °C. In argon, amorphous Sb₂S₃formed as

the product of the frst decomposition step by 170 °C along-

side a minor amount of possibly antimony monothiocarbonate

The third decomposition step in synthetic air occurred

in the range of 250–495 °C, with a mass loss of 1.0%,

accompanied by evolution of SO₂(Fig. 3), and a mix of

Sb₂O₄and Sb₂O₃as the fnal product (Table 3). As seen

in Fig. 6b, at 350 °C in air the gray residue contained at

least one sulfate of antimony (Sb₂(S₂O₇)₃) in addition to

Sb₂S₃, and Sb₂O₄(cervantite), indicating that in the third

decomposition step, any remaining Sb₂S₃is frst oxidized to

1 3

Thermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III)—a single-source…

Sb(CSO₂)₃, Sb(OEt)₃, Sb(SEt)₃or a mixed ligand compound

containing these ligands, identifed by EGA-MS and FTIR of

intermediate decomposition products. In synthetic air, amor-

phous senarmontite-Sb₂O₃formed by 170 °C in addition to

the aforementioned compounds, as identifed by Raman. In the

frst decomposition step, CS₂, EtOH, CO, CO₂, COS, H₂O, and

SO₂evolved as main gases. Evolution of minor gases EtSH,

Et₂S, Et₂O, and (EX)₂was also detected.

Electronic Supporting Material

The electronic Supplementary File contains the tabulated

list of tentative FTIR vibrational assignments from the lit-

erature used in this study, the Raman spectrum of 1 in the

range of 50–3000 cm⁻¹, and the corresponding tabulated

list of tentative Raman vibrational assignments from the lit-

erature, the powder XRD pattern of 1, and the correspond-

ing numeric XRD data, the HMBC plot of 1, EGA-MS gas

evolution curves of additional gaseous species, and peak

centers and proposed assignments of all m/z channels used

in the EGA-MS.

Chemical reactions occurring in the frst decomposition

step in the temperature range of 90–170 °C were proposed

for the frst time for SbEX, describing formation of CS₂,

COS, CO₂, EtOH, EtSH, Et₂S, Et₂O, and intermediate

decomposition product ligands, e.g., EtS, EtO, and (mono-

thio)carbonyl-based unsubstituted and the respective alkyl-

substituted ligands. Furthermore, the results of this study

show that the Chugaev elimination reaction is inadequate to

describe the thermal decomposition of SbEX.

Supplementary Information The online version contains supplemen-

tary material available at https://doi.org/10.1007/s10973-021-10885-1.

Acknowledgements The authors thank Dr. Valdek Mikli from the

Laboratory of Optoelectronic Materials Physics at Tallinn University

of Technology for EDX measurements. This study was funded by the

Estonian Research Council project PRG627 “Antimony chalcogenide

thin flms for next-generation semitransparent solar cells applicable

in electricity producing windows,” European Regional Development

Fund Centre of Excellence project TK141 (TAR16016EK) “Advanced

materials and high-technology devices for energy recuperation sys-

tems,” and European Regional Development Fund Centre of Excellence

project TK134 “Emerging orders in quantum and nanomaterials.”

In the second thermal decomposition step in argon, the

solid phase was purifed from the remaining ligands, and

thereafter Sb₂S₃crystallized, as confrmed by XRD and

Raman. In synthetic air, the solid phase contained amor-

phous senarmontite-Sb₂O₃, as confirmed by XRD and

Raman. The evolved gases in the second thermal decom-

position step were the same as in the frst step, although

evolution of CS₂and EtOH had diminished considerably. In

argon, the third and fnal thermal decomposition step began

at 590 °C, after melting of Sb₂S₃at 550 °C, and proceeded

apace until total mass loss at 800 °C. In air, the third decom-

position step began at 250 °C, and ended at 495 °C with the

formation of cervantite-Sb₂O₄, proceeding through forma-

tion and oxidation of a mixture of antimony sulfates coupled

with vigorous evolution of SO₂(EGA-MS), as shown for the

frst time for SbEX through solid-phase intermediate decom-

position product analysis in this study by XRD and Raman.

In the fourth decomposition step in synthetic air, remaining

antimony sulfates oxidized into cervantite-Sb₂O₄, as con-

frmed by XRD of the fnal product remaining at 600 °C,

coupled with evolution of SO₂according to EGA-MS. Nei-

ther evolution of carbonaceous species, nor any presence in

the solid state in either atmosphere in intermediate decom-

position products prepared at or above 270 °C was detected,

indicating that the solid state is free of carbon residues.

Results on the thermal decomposition of tris-ethyldithi-

ocarbonato-antimony(III) (1) in inert and oxidative atmos-

pheres yielded valuable data serving as basis for determin-

ing the atmosphere and processing temperatures to be used

to deposit phase pure Sb₂S₃thin flms. The fact that SbEX

allows to deposit Sb₂S₃at signifcantly lower temperatures in

comparison to other single-source precursors, and is purifed

from C containing residues at very low temperatures, makes

SbEX a suitable precursor for depositing phase pure Sb₂S₃

thin flms by the spray pyrolysis method.

Author contributions All authors contributed to the study conception

and design. Material preparation was performed by J.S. Eensalu. Data

collection was performed by J.S. Eensalu, K. Tõnsuaadu and J. Adam-

son. All authors participated in the data analysis. The frst draft of the

manuscript was written by J.S. Eensalu and all authors commented on

previous versions of the manuscript. All authors read and approved the

fnal and the revised manuscript.

Funding This study was funded by the Estonian Research Council pro-

ject PRG627 “Antimony chalcogenide thin flms for next-generation

semitransparent solar cells applicable in electricity producing win-

dows,” European Regional Development Fund Centre of Excellence

project TK141 (TAR16016EK) “Advanced materials and high-technol-

ogy devices for energy recuperation systems,” and European Regional

Development Fund Centre of Excellence project TK134 “Emerging

orders in quantum and nanomaterials.”

Data availability Data and materials are available upon request from

the authors.

Declarations

Conflict of interest The authors declare that they have no confict of

interest.

Open Access This article is licensed under a Creative Commons Attri-

bution 4.0 International License, which permits use, sharing, adapta-

tion, distribution and reproduction in any medium or format, as long

as you give appropriate credit to the original author(s) and the source,

provide a link to the Creative Commons licence, and indicate if changes

were made. The images or other third party material in this article are

included in the article’s Creative Commons licence, unless indicated

otherwise in a credit line to the material. If material is not included in

the article’s Creative Commons licence and your intended use is not

1 3

J. S. Eensalu et al.

permitted by statutory regulation or exceeds the permitted use, you will

need to obtain permission directly from the copyright holder. To view a

copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

18. Kaienburg P, Klingebiel B, Kirchartz T. Spin-coated planar Sb₂S₃

hybrid solar cells approaching 5% efciency. Beilstein J Nanotech-

nol. 2018;9:2114–24.

19. Jiang C, Tang R, Wang X, Ju H, Chen G, Chen T. Alkali metals

doping for high-performance planar heterojunction Sb₂S₃solar

cells. Solar RRL. 2019;3:1800272.

20. Kriisa M, Krunks M, Oja Acik I, Kärber E, Mikli V. The efect

of tartaric acid in the deposition of Sb₂S₃flms by chemical spray

pyrolysis. Mater Sci Semicond Process. 2015;40:867–72.

21. Kärber E, Katerski A, Oja Acik I, Mere A, Mikli V, Krunks M.

Sb₂S₃grown by ultrasonic spray pyrolysis and its application in a

hybrid solar cell. Beilstein J Nanotechnol. 2016;7:1662–73.

22. Eensalu JS, Katerski A, Kärber E, Oja Acik I, Mere A, Krunks

M. Uniform Sb₂S₃optical coatings by chemical spray method.

Beilstein J Nanotechnol. 2019;10:198–210.

References

1. Klochko K. Antimony Data Sheet. In: Mineral commodity sum-

maries. U. S. Geological Survey. 2020. Available from: https://

pubs.usgs.gov/periodicals/mcs2020/mcs2020-antimony.pdf .

Accessed 13 May 2020.

2. Apodaca LE. Sulfur Data Sheet. In: Mineral commodity summa-

ries. U. S. Geological Survey; 2020. Available from: https://pubs.

usgs.gov/periodicals/mcs2020/mcs2020-sulfur.pdf . Accessed 13

May 2020.

23. Deng H, Yuan S, Yang X, Cai F, Hu C, Qiao K, et al. Efcient

and stable TiO₂/Sb₂S₃planar solar cells from absorber crystal-

lization and Se-atmosphere annealing. Mater Today Energy.

2017;3:15–23.

3. Alharbi F, Bass JD, Salhi A, Alyamani A, Kim H-C, Miller RD.

Abundant non-toxic materials for thin flm solar cells: alternative

to conventional materials. Renew Energy. 2011;36:2753–8.

4. Greenwood NN, Earnshaw A. Chemistry of the elements. 2nd ed.

Oxford: Butterworth-Heinemann; 1997.

24. Choi YC, Lee DU, Noh JH, Kim EK, Seok SI. Highly improved

Sb₂S₃sensitized-inorganic–organic heterojunction solar cells and

quantifcation of traps by deep-level transient spectroscopy. Adv

Funct Mater. 2014;24:3587–92.

5. Thorneycroft WE. Antimony and bismuth. London: Charles Grif-

fn & Co Ltd; 1936.

25. Patil PS. Versatility of chemical spray pyrolysis technique. Mater

Chem Phys. 1999;59:185–98.

6. Rinkevichius V, Mikalkevichius M. Pyroelectric efect in anti-

mony trisulfide single crystals. Sov Phys Solid State USSR.

1967;9:2360.

26. Krunks M, Leskelä T, Mutikainen I, Niinistö L. A Thermoanalyti-

cal study of copper(I) thiocarbamide compounds. J Therm Anal

Calorim. 1999;56:479–84.

7. Živković Ž, Štrbac N, Živković D, Grujičić D, Boyanov B. Kinet-

ics and mechanism of Sb₂S₃oxidation process. Thermochim Acta.

2002;383:137–43.

27. Otto K, Oja Acik I, Tõnsuaadu K, Mere A, Krunks M. Thermo-

analytical study of precursors for In₂S₃thin flms deposited by

spray pyrolysis. J Therm Anal Calorim. 2011;105:615–23.

28. Oja Acik I, Otto K, Krunks M, Tõnsuaadu K, Mere A. Thermal

behaviour of precursors for CuInS₂thin flms deposited by spray

pyrolysis. J Therm Anal Calorim. 2013;113:1455–65.

29. Krunks M, Madarász J, Leskelä T, Mere A, Niinistö L, Pokol G.

Study of zinc thiocarbamide chloride, a single-source precursor

for zinc sulfde thin flms by spray pyrolysis. J Therm Anal Calo-

rim. 2003;72:497–506.

8. Leijtens T, Bush KA, Prasanna R, McGehee MD. Opportunities

and challenges for tandem solar cells using metal halide perovs-

kite semiconductors. Nat Energy. 2018;3:828–38.

9. Kondrotas R, Chen C, Tang J. Sb₂S₃Solar cells. Joule.

2018;2:857–78.

10. Shin HD, Choi S-H. Recent studies of semitransparent solar cells.

Coatings. 2018;8:329–58.

11. Eensalu JS, Katerski A, Kärber E, Weinhardt L, Blum M, Heske

C, et al. Semitransparent Sb₂S₃thin flm solar cells by ultrasonic

spray pyrolysis for use in solar windows. Beilstein J Nanotechnol.

2019;10:2396–409.

30. Madarász J, Krunks M, Niinistö L, Pokol G. Evolved gas analy-

sis of dichlorobis(thiourea)zinc(II) by coupled TG-FTIR and TG/

DTA-MS techniques. J Therm Anal Calorim. 2004;78:679–86.

31. Polivtseva S, Oja Acik I, Krunks M, Tõnsuaadu K, Mere A.

Thermoanalytical study of precursors for tin sulfde thin flms

deposited by chemical spray pyrolysis. J Therm Anal Calorim.

2015;121:177–85.

12. Savadogo O, Mandal KC. Studies on new chemically deposited

photoconducting antimony trisulphide thin flms. Sol Energ Mat

Sol Cells. 1992;26:117–36.

13. Zimmermann E, Pfadler T, Kalb J, Dorman JA, Sommer D,

Hahn G, et al. Toward high-efciency solution-processed pla-

nar heterojunction Sb₂S₃solar cells. Adv Sci (Weinheim, Ger).

2015;2:1500059.

32. Khwaja MA, Cardwell TJ, Magee RJ. Thermal studies on arsenic,

antimony and bismuth alkylxanthate complexes. Anal Chim Acta.

1973;64:9–17.

14. Parize R, Cossuet T, Chaix-Pluchery O, Roussel H, Appert E,

Consonni V. In situ analysis of the crystallization process of Sb₂S₃

thin flms by Raman scattering and X-ray difraction. Mater Des.

2017;121:1–10.

33. Rodriguez-Castro J, Molloy KC, Liu Y, Lai CS, Dong Z, White

TJ, et al. Formation of antimony sulfide powders and thin

flms from single-source antimony precursors. J Mater Chem.

2008;18:5399–405.

15. Wedemeyer H, Michels J, Chmielowski R, Bourdais S, Muto T,

Sugiura M, et al. Nanocrystalline solar cells with an antimony

sulfde solid absorber by atomic layer deposition. Energy Environ

Sci. 2013;6:67–71.

34. Vreugdenhil AJ, Brienne SHR, Butler IS, Finch JA, Markwell

RD. Infrared spectroscopic determination of the gas-phase ther-

mal decomposition products of metal-ethyldithiocarbonate com-

plexes. Spectrochim Acta, Part A. 1997;53:2139–51.

35. DePuy CH, King RW. Pyrolytic cis eliminations. Chem Rev.

1960;60:431–57.

16. Kim D-H, Lee S-J, Park MS, Kang J-K, Heo JH, Im SH, et al.

Highly reproducible planar Sb₂S₃-sensitized solar cells based on

atomic layer deposition. Nanoscale. 2014;6:14549–54.

17. Büttner P, Scheler F, Pointer C, Döhler D, Barr MKS, Koroleva

A, et al. Adjusting interfacial chemistry and electronic properties

of photovoltaics based on a highly pure Sb₂S₃absorber by atomic

layer deposition. ACS Appl Energy Mater. 2019;2:8747–56.

36. Chakrabarty T, De AK. Liquid-liquid extraction of arsenic(III),

antimony(III) and bismuth(III) with potassium ethyl xanthate.

Fresenius’ J Anal Chem. 1968;242:152–9.

37. Zard SZ. On the trail of xanthates: some new chemistry from an

old functional group. Angew Chem, Int Ed Engl. 1997;36:672–85.

38. Talonen P, Sundholm G, Li WH, Floate S, Nichols RJ. A com-

bined in situ infrared spectroscopy and scanning tunnelling

1 3

Thermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III)—a single-source…

microscopy study of ethyl xanthate adsorption on Au(111). Phys

Chem Chem Phys. 1999;1:3661–6.

and a redetermination for tris(O-ethylxanthato)antimony(III).

Inorg Chim Acta. 1985;97:217–22.

39. Li J, Liu X, Yao J. The enhanced photovoltaic performance of

Sb₂S₃solar cells by thermal decomposition of antimony ethyl

xanthate with thiourea doping. Energy Technol (Weinheim, Ger).

2020;8:1900841.

53. Fulmer GR, Miller AJM, Sherden NH, Gottlieb HE, Nudelman

A, Stoltz BM, et al. NMR chemical shifts of trace impurities:

common laboratory solvents, organics, and gases in deuterated

solvents relevant to the organometallic chemist. Organometallics.

2010;29:2176–9.

40. Garje SS, Jain VK. Chemistry of arsenic, antimony and bismuth

compounds derived from xanthate, dithiocarbamate and phospho-

rus based ligands. Coord Chem Rev. 2003;236:35–56.

41. Ray A, Sathyanarayana DN, Prasad GD, Patel CC. Infrared

spectral assignments of methyl and ethyl xanthato complexes of

nickel(II). Spectrochim Acta, Part A. 1973;29:1579–84.

42. Buchmaier C, Glänzer M, Torvisco A, Poelt P, Wewerka K, Kunert

B, et al. Nickel sulfde thin flms and nanocrystals synthesized

from nickel xanthate precursors. J Mater Sci. 2017;52:10898–914.

43. Barreca D, Gasparotto A, Maragno C, Seraglia R, Tondello E,

Venzo A, et al. Synthesis and characterization of zinc bis(O-

isopropylxanthate) as a single-source chemical vapor deposition

precursor for ZnS. Appl Organomet Chem. 2005;19:1002–9.

44. Vigneshwaran M, Ohta T, Iikubo S, Kapil G, Ripolles TS, Ogomi

Y, et al. Facile synthesis and characterization of sulfur doped low

bandgap bismuth based perovskites by soluble precursor route.

Chem Mater. 2016;28:6436–40.

54. Padilla R, Ramírez G, Ruiz MC. High-temperature volatilization

mechanism of stibnite in nitrogen-oxygen atmospheres. Metall

Mater Trans B. 2010;41:1284–92.

55. IR spectrum table & chart. Merck KGaA. https://www.sigmaaldri

ch.com/technical-documents/articles/biology/ir-spectrum-table.

html . Accessed 10 Jul 2020.

56. Fisher NG, Dunn JG. Identifying organic foulants on activated

carbon from gold processing plants. Miner Eng. 2000;13:1581–8.

57. Fan H-T, Sun W, Jiang B, Wang Q-J, Li D-W, Huang C-C, et al.

Adsorption of antimony(III) from aqueous solution by mercapto-

functionalized silica-supported organic–inorganic hybrid sorbent:

Mechanism insights. Chem Eng J (Amst, Neth). 2016;286:128–38.

58. Stueber D, Patterson D, Mayne CL, Orendt AM, Grant DM, Parry

RW. Carbonates, thiocarbonates, and the corresponding mono-

alkyl derivatives. 1. Their preparation and isotropic ¹³C NMR

chemical shifts. Inorg Chem. 2001;40:1902–11.

45. Bansal N, O’Mahony FTF, Lutz T, Haque SA. Solution processed

polymer–inorganic semiconductor solar cells employing Sb₂S₃as

a light harvesting and electron transporting material. Adv Energy

Mater. 2013;3:986–90.

59. Ferm RJ. The chemistry of carbonyl sulfide. Chem Rev.

1957;57:621–40.

60. Padilla R, Aracena A, Ruiz MC. Kinetics of stibnite (Sb₂S₃)

oxidation at roasting temperatures. J Min Metall Sect B.

2014;50:127–32.

46. Wojdyr M. Fityk: a general-purpose peak ftting program. J Appl

Crystallogr. 2010;43:1126–8.

61. Polivtseva S, Katerski A, Kärber E, Oja Acik I, Mere A, Mikli V,

Krunks M. Post-deposition treatment of sprayed SnS flms. Thin

Solid Films. 2017;633:179–84.

47. NIST chemistry webbook. National Institute of Standards and

Technology. https://webbook.nist.gov/chemistry/. Accessed 28

July 2020.

62. Dedova T, Krunks M, Gromyko I, Mikli V, Sildos I, Utt K, et al.

Efect of Zn:S molar ratio in solution on the properties of ZnS thin

flms and the formation of ZnS nanorods by spray pyrolysis. Phys

Status Solidi A. 2014;211:514–21.

48. Juncal LC, Cozzarín MV, Romano RM. Conformational and

spectroscopic study of xanthogen ethyl formates, ROC(S)SC(O)

OCH₂CH₃. Isolation of CH₃CH₂OC(O)SH. Spectrochim Acta,

Part A. 2015;139:346–55.

63. Otto K, Katerski A, Mere A, Volobujeva O, Krunks M. Spray

pyrolysis deposition of indium sulphide thin flms. Thin Solid

Films. 2011;519:3055–60.

49. Chandra AP, Puskar L, Simpson DJ, Gerson AR. Copper

and xanthate adsorption onto pyrite surfaces: implications

for mineral separation through fotation. Int J Miner Process.

2012;114–117:16–26.

64. Krunks M, Mikli V, Bijakina O, Rebane H, Mere A, Varema T,

Mellikov E. Composition and structure of CuInS₂flms prepared

by spray pyrolysis. Thin Solid Films. 2000;361–362:61–4.

50. Woods R, Hope GA. Spectroelectrochemical investigations of the

interaction of ethyl xanthate with copper, silver and gold: I. FT-

Raman and NMR spectra of the xanthate compounds. Colloids

Surf A. 1998;137:319–28.

Publisher’s Note Springer Nature remains neutral with regard to

jurisdictional claims in published maps and institutional afliations.

51. Gottardi G. The crystal structure of xanthates II Antimonious

xanthate. Z Kristallogr Cryst Mater. 1961;115:451–9.

52. Hoskins BF, Tiekink ERT, Winter G. The crystal and molecular

structure of O-ethylxanthato-bis(quinolin-8-olato)antimony(III)

1 3

Article Doi

Thermal decomposition of tris(O-ethyldithiocarbonato)-antimony(III)—a single-source precursor for antimony sulfide thin films

DOI: 10.1007/s10973-021-10885-1

Source and publish data:

Authors:

Article abstract of DOI:10.1007/s10973-021-10885-1

Full text of DOI:10.1007/s10973-021-10885-1

Products guided by the article

R&D Labs maybe for 7440-36-0

Relevant to this article

Hot Product