The crystal structure of thallium(I) trithiocarbonate, Tl 2CS3

Article abstract of DOI:10.1002/zaac.200801408

Thallium trithiocarbonate, T1₂CS₃, was prepared by the reaction of Na₂CS₃ with T1NO₃ in aqueous solution. T1₂CS₃ has a low solubility and is precipitated as an orange powder. DSC

Full text of DOI:10.1002/zaac.200801408

ARTICLE
DOI: 10.1002/zaac.200801408
The Crystal Structure of Thallium(I) Trithiocarbonate, Tl2CS3
Johannes Beck*[a] and Sebastian Benz[a]
Dedicated to Professor Gerd Meyer on the Occasion of His 60th Birthday
Keywords: Thallium; Trithiocarbonate; Crystal structure; Powder diffraction; Raman spectroscopy; IR spectroscopy
Abstract. Thallium trithiocarbonate, Tl2CS3, was prepared by the
reaction of Na2CS3 with TlNO3 in aqueous solution. Tl2CS3 has a
low solubility and is precipitated as an orange powder. DSC meas-
urements show Tl2CS3 to be stable up to 155 °C. Above this tem-
perature exothermic decomposition under evolution of CS2 occurs.
The crystal structure was determined based on powder diffraction
data and Rietveld refinement (monoclinic, C2/c, a ϭ 1143.33(1),
b ϭ 627.70(1), c ϭ 916.03(1) pm, β ϭ 118.77(1)°, Z ϭ 4). The
structure shows a close relationship and is isopointal to the struc-
ture of β-Na2CS3 (Henseler, Jansen 1992). Tlϩ has an irregular
nonacoordination. The overall arrangement of the ions can be de-
scribed as being analog to the anti-CaF2 structure type with Tlϩ
2Ϫ
making up a strongly distorted primitive cubic array and CS3
occupying one half of the cubical cavities. In the crystal, the D3h
symmetry of the CS32Ϫ ions is lowered to the site symmetry C2 and
a slight angular deformation is observed. This loss of symmetry
is also observed in the Raman and IR spectra by the splitting of
degenerate modes.
Introduction
Experimental Section
Na2CS3 was prepared from sodium metal, ethanol, H2S and CS2
according to the procedure described by Yeoman [7]. Tl2CS3 was
prepared by precipitation from aqueous solutions of TlNO3 and
Na2CS3 according to [7] and was obtained as an insoluble, orange
colored powder, which was filtered off, washed thoroughly with
water and dried in vacuo.
Trithiocarbonic acid, SC(SH)2, forms a series of stable
salts, of which the Naϩ, Kϩ [1], Ba2ϩ, Cd2ϩ, and the Tlϩ
salt are well known as the most stable [2]. The thermochem-
ical properties of Tl2CS3 have been explored by its dis-
sociation gas pressure resulting in the heat of formation of
Ϫ88 kJ·molϪ1 [2]. Structural data on trithiocarbonates are
rare. The structures of the hydrates K2CS3 ·H2O [3] and
Cs2CS3 ·H2O [4] are known. Of the solvent free trithiocar-
bonates, only the structure of Na2CS3 has been determined
on single crystals grown under solvothermal conditions
from Na2S and CS2 in the presence of ethanol [5]. Na2CS3
has been shown to be a fairly good ion conductor at elev-
ated temperatures.
Infrared spectra were recorded with a FT spectrometer Bruker IFS
113v and Raman spectra with a Bruker RFS 100 spectrometer. The
thermal analysis was performed between ambient temperature and
250 °C with a differential scanning calorimeter Netzsch DSC 204
F1 Phoenix. The sample was included in a closed aluminum cru-
cible and heated with a temperature gradient of 10 °C·minϪ1
.
In preceding vibrational spectroscopy studies on BaCS3,
PbCS3, CdCS3, and Tl2CS3 it was shown that the symmetry
of the anion in the crystals must be lower than D3h. Space
groups with three fold rotation axes running through the
anion should therefore not be taken into consideration [6].
The crystal structure of Tl2CS3 was so far not determined
what may be caused by the low solubility. In the prepa-
ration process only fine, microcrystalline powders can be
obtained. We succeeded now to ascertain the crystal struc-
ture based on powder diffraction data.
Crystal Structure Analysis
Powder diffractograms were recorded with a Bruker D8 dif-
fractometer equipped with a positional sensitive detector and
Cu-Kα1 radiation in DebyeϪScherrer geometry. Samples were filled
in thin-walled glass capillaries with a diameter of 0.2 mm and
11942 data points were recorded in the 2θ range up to 91.5°. In-
dexing of the diffractogram and determination of the lattice param-
eters was performed using the program WinXPow [8]. A structure
model was obtained by the program ENDEAVOUR [9]. A first
kind Chebyshev background function with 16 terms was applied as
implemented in the GSAS program system [10]. Refinement of the
lattice parameters, the atom positions, and the isotropic displace-
ment parameters was performed with the program GSAS. A
Pseudovoigt function with 19 terms was used to fit the reflection
profiles for all 486 identified reflections. The observed and the
calculated powder diffractograms are shown in Figure 1. Crystallo-
graphic data are summarized in Table 1, the positional parameters
are included in Table 2, and important bond lengths and angles are
* Prof. Dr. J. Beck
E-Mail: j.beck@uni-bonn.de
[a] Institut für Anorganische Chemie
Universität Bonn
Gerhard-Domagk-Str. 1
53121 Bonn, Germany
962
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2009, 635, 962Ϫ965

The Crystal Structure of Thallium(I) Trithiocarbonate, Tl2CS3
Table 3. Selected bond lengths /pm and angles /° for Tl2CS3. Stan-
dard deviations are given in brackets and refer to the last signifi-
cant digit.
TlϪS(2)III
TlϪS(1)IV
TlϪS(1)VI
TlϪS(1)
305.895(3)
312.729(2)
326.489(3)
328.056(2)
330.585(2)
339.281(2)
360.564(3)
372.426(4)
TlϪS(1)II
C Ϫ S(1)I
C Ϫ S(1)VIII
C Ϫ S(2)
408.372(3)
169.40(1)
169.40(1)
169.58(1)
TlϪS(1)I
TlϪS(2)V
TlϪS(2)
S(1)I Ϫ C ϪS(2)
121.345(1)
121.345(1)
117.311(1)
S(2) Ϫ C ϪS(1)VIII
S(1)I Ϫ C ϪS(1)VIII
TlϪS(1)VII
Symmetry operations: I ϭ 0.5 Ϫ x, Ϫ0.5 ϩ y, 0.5 Ϫ z; II ϭ x, Ϫy,
0.5 ϩ z; II ϭ 0.5 Ϫ x, 0.5 Ϫ y, 1 Ϫz; IV ϭ x, 1 Ϫy, 0.5 ϩ z; V ϭ
0.5 ϩ x, Ϫ0.5 ϩ y, z; VI ϭ 1 Ϫx, y, 0.5 Ϫ z; VII ϭ 0.5 Ϫ x, 0.5
Ϫ y, Ϫz; VIII ϭ Ϫ0.5 ϩ x, Ϫ0.5 ϩ y, z.
Further details of the crystal structure investigation may be
obtained from Fachinformationszentrum Karlsruhe, 76344 Eggen-
Figure 1. Powder diffractogram of Tl2CS3. Shown are the measured
intensities, the calculated intensities, the background function, and
the difference graph Iobs-Icalcd. The inset shows an enlargement of
the high angle region of the diffractogram.
stein-Leopoldshafen,
Germany
(http://www.fiz-karlsruhe.de/
request_for_deposited_data.html) on quoting the CSD number
420223.
Table 1. Crystallographic data and details of structure determina-
tion for Tl2CS3. Standard deviations are given in brackets and refer
to the last significant digit.
Results and Discussion
Crystal Structure of Tl2CS3
Compound
Tl2CS3
2Ϫ
The crystal structure of Tl2CS3 is built of Tlϩ and CS3
Formula
CS3Tl2
516.93
monoclinic
C2/c
1143.33(1)
627.80(1)
916.10(1)
118.77(1)
576.40(2)
4
ions. The trithiocarbonate ions are located on twofold axes
running through the atoms C and S(2). The ideal point
symmetry D3h of the ion is lowered to C2. The actual devi-
ations are, however, small. The rotation axis causes the CS3
group to be strictly planar. The two independent CϪS
bonds differ by only 0.2 pm and the two independent S-C-
S angles are 117.3° and 2 ϫ 121.3°. In the structure, all CS3
groups are in a parallel arrangement with the Tlϩ ions lo-
cated between these planes (Figure 2). Taking into account
the position of the carbon atoms, within a sphere of radius
Formula weight /g·molϪ1
Crystal system
Space group
˚
a /A
˚
b /A
˚
c /A
β /°
3
˚
V /A
Number of formula units Z
Density (calcd.) /g·cmϪ3
μ /mmϪ1
Diffractometer
Radiation
5.96
115.1
Bruker D8
Cu-Kα, λ ϭ 154.0598 pm
293
4 < 2Θ < 91.5
17
0.0345
0.0258
2Ϫ
470 pm the Tlϩ ions are coordinated by four CS3 ions.
Expanding this sphere to a radius of 560 pm brings two
additional anions into the coordination sphere. Three of the
anions act as monodentate ligands with one coordinating
sulfur atom and three as chelating ligands with two coordi-
nating sulfur atoms giving the Tlϩ ion the coordination
number 9 forming a rather irregular polyhedron (Figure 3).
The respective TlϪS distances are in the range between
305.9 and 408.4 pm.
Temperature /K
Range of data collection /°
Number of refined parameters
Rwp
R(ΗF2Η)
R(ΗFΗ) for all data
0.109
ϩ0.52 / Ϫ0.71
Ϫ3
˚
Largest difference peak and hole /e·A
Table 2. Positional parameters and displacement parameters
Uiso /106 pm3 for the atoms in the structure of Tl2CS3. Standard
deviations are given in brackets and refer to the last significant
digit.
The crystal structure is closely related to the structure of
β-Na2CS3 [5]. A significant difference is the lower coordi-
nation number of the Naϩ ion in comparison to Tlϩ. Both
structures can be derived from the anti-CaF2 or Li2O struc-
ture type. The Tlϩ ions form a distorted primitive cubic
array with every second cubical cavity filled by a CS32Ϫ ion
(Figure 4). The distortion from the cubic arrangement,
however, is stronger in the case of Tl2CS3 than for β-
Na2CS3. Since both structures share the same space group
type and have comparable lattice constants and atom posi-
tions, the structure relation of Tl2CS3 and β-Na2CS3 is best
characterized as isopointal [13].
Atom
x
y
z
Uiso
C
0
0.0504(1)
0.4100(1)
0.3205(1)
0.1775(1)
0.25
0.0827(1)
0.25
0.022(5)
S(1)
S(2)
Tl
0.3886(1)
0
0.3398(1)
0.0344(8)
0.0256(8)
0.0409(2)
0.3696(1)
presented in Table 3. The graphical representations were made with
the programs Diamond [11] and Pov-Ray [12].
Z. Anorg. Allg. Chem. 2009, 962Ϫ965
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963

J. Beck, S. Benz
ARTICLE
Figure 4. Alternative view on the structure of Tl2CS3 to point out
Figure 2. The unit cell of Tl2CS3. The atoms are represented by
displacement spheres drawn with radii scaled to enclose a probabi-
lity density of 50 %.
the relation to the CaF2 structure type. The distorted cubical net
2Ϫ
made up by the Tlϩ ions is shown, and the CS3 ions occupying
one half of the cubical-shaped interstices. Additionally, the crystal-
lographic unit cell is shown with thick lines.
Tl2CO3 is made up of layers -Tl-CO3-Tl-ᮀ-Tl-CO3- with a
hexagonal closest packing of the Tlϩ ions and CO32Ϫ filling
all octahedral holes in every second layer [14]. Tl2CO3 has a
structural arrangement of the anti-CdI2 or Ag2F type. This
shows the effect of the harder, less polarizable cabonate ion
in comparison to the soft trithiocarbonate. The harder
anion polarizes the TlI ion with the result of a pronounced
lone pair effect and a van der Waals gap in the structure.
In the structure of Tl2CS3 the Tlϩ ion does not exhibit a
distinct stereochemical effect of the lone electron pair.
Thermal Properties
The thermal properties of Tl2CS3 have been investigated
by a DSC measurement, which showed thermal stability
and no sign of phase transitions up to 150 °C. With an on-
set temperature of 155 °C an exothermic decomposition
process over a broad temperature range of 50 °C ac-
companied by evolution of gas (CS2) is detected. The ther-
Figure 3. The coordination polyhedron around the Tlϩ ion in the
structure of Tl2CS3. For symmetry operations see legend of Table 3.
Tl2CS3 does not show a structure relation to its oxygen mal stability for Tl2CS3 is thus lower than for β-Na2CS3,
containing congener thallium(I) carbonate. The structure of which decomposes above 250 °C.
964
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Z. Anorg. Allg. Chem. 2009, 962Ϫ965

The Crystal Structure of Thallium(I) Trithiocarbonate, Tl2CS3
Vibrational Spectroscopy
Table 4. Raman and infrared frequencies of solid Tl2CS3 with attri-
2Ϫ
bution of molecular normal modes for the free CS3 ion with
2Ϫ
point symmetry D3h and for CS3 in the crystal lattice with site
The infrared spectra of trithiocarbonates including
Tl2CS3 have already been recorded and a detailed analysis
of the vibration modes was performed. The analysis showed
that in the crystal the symmetry of the CS32Ϫ ion is reduced
from D3h to C2v, C2, or CS [6]. The actual site symmetry C2
for the CS3 group confirms this prediction. In the infrared
spectrum of β-Na2CS3 seven bands were found, which were
attributed to four normal vibrations [5]. We performed ad-
ditionally Raman spectra of Tl2CS3. Besides a poorly re-
solved broad lattice vibration band around 120 cmϪ1, in the
region between 300Ϫ1000 cmϪ1, four sharp lines and one
broader line were observed. Three of the four possible vi-
brations in the point group D3h are Raman active. In the
symmetry C2 the degeneration of the asymmetrical valence
vibration νasym and the in-plane deformation mode is no
longer valid. The out-of-plane deformation mode becomes
Raman active and the symmetrical valence vibration be-
comes IR active. So one would expect six observable vi-
brations for the trithiocarbonate ion. The broad band in
the Raman spectrum at 875 cmϪ1 can be attributed to two
not resolved bands of the asymmetric valence vibration.
The occurrence of an IR band at 884 cmϪ1 can be explained
by the factor group analysis. All internal vibrations of A
and B character in point group C2 are split in the factor
group C2h (2/m) into two independent vibrations Ag and Au
and Bg and Bu, respectively, which are alternatively IR (u)
or Raman (g) active. Thus, these two bands with a small
but significant difference in energy may originate from the
coupling of vibrations due to the presence of two indepen-
dent CS32Ϫ ions in the vibrational spectroscopic unit cell. In
the IR spectrum an overlap of the out-of-plane deformation
vibration and the symmetrical valence vibration at
494 cmϪ1 is present and the splitting of the in-plane defor-
mation mode caused by the breakup of degeneracy cannot
be resolved. Table 4 summarizes the observed bands in the
vibration spectra and the respective attribution.
symmetry C2.
Raman /cmϪ1
IR /cmϪ1
Attribution
D3h
C2
304
314
495
501
875
311
311
494
494
884
δin plane
δin plane
δout of plane
νsym
EЈ
EЈ
A2Љ
A1Ј
EЈ
AϩB
AϩB
B
A
AϩB
νasym
tra are in line with the crystal structure and reveal the sym-
metry reduction of the CS32Ϫ anion from D3h to C2. A close
structural relation is present to β-Na2CS3 but no relation to
the structure of Tl2CO3 exists.
Acknowledgement
We are obliged to D. Ernsthäuser for the fruitful discussions on the
interpretation of the vibrational spectra.
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The crystal structure of thallium trithiocarbonate was de-
termined by X-ray powder diffraction. The vibration spec-
Received: December 28, 2008
Published Online: April 9, 2009
Z. Anorg. Allg. Chem. 2009, 962Ϫ965
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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