Interaction of bismuth(III) oxide with formic acid solutions

Article abstract of DOI:10.1134/S0036023612040201

The interaction of bismuth(III) oxide with formic acid solutions at 22 and 55°C was studied using X-ray powder diffraction, thermogravimetry electron microscopy, IR spectroscopy, and chemical analysis. Solubility curves were found to comprise two branches due to formates of compositions Bi(COOH)₃ and BiOCOOH forming in the system. Thermal decomposition of bismuth formates is shown to be a promising route for the synthesis of metallic bismuth, as well as of tetragonal (β) and monoclinic (a) bismuth oxides.

Full text of DOI:10.1134/S0036023612040201

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2012, Vol. 57, No. 4, pp. 564–568. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © K.V. Mishchenko, Yu.M. Yukhin, I.A. Vorsina, 2012, published in Zhurnal Neorganicheskoi Khimii, 2012, Vol. 57, No. 4, pp. 628–632.
PHYSICAL METHODS
OF INVESTIGATION
Interaction of Bismuth(III) Oxide with Formic Acid Solutions
K. V. Mishchenko, Yu. M. Yukhin, and I. A. Vorsina
Institute of SolidꢀState Chemistry and Mechanochemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Received January 25, 2011
Abstract—The interaction of bismuth(III) oxide with formic acid solutions at 22 and 55 C was studied using
°
Xꢀray powder diffraction, thermogravimetry, electron microscopy, IR spectroscopy, and chemical analysis.
Solubility curves were found to comprise two branches due to formates of compositions Bi(COOH)3 and
BiOCOOH forming in the system. Thermal decomposition of bismuth formates is shown to be a promising
route for the synthesis of metallic bismuth, as well as of tetragonal (
β
) and monoclinic ( ) bismuth oxides.
α
DOI: 10.1134/S0036023612040201
Bismuth carboxylates are used in the synthesis of muth oxide with 30 mL of formic acid solution under
boiling for 10 min.
bismuthꢀcontaining oxide materials (superconductor,
ferroelectrics, piezoelectrics, catalysts, and other materiꢀ
als) and bismuthꢀcontaining medicaments [1–3]. In this
context, it is pertinent to develop simple and reliable
methods for preparing these materials. Bismuth forꢀ
mate is the best studied bismuth carboxylate; its low
decomposition makes it a promising precursor for preꢀ
paring both metallic bismuth and bismuth oxide.
Here, we study the interaction of bismuth oxide
with formic acid solutions of various concentrations at
22 1 and 55 2
°С.
EXPERIMENTAL
The reagents used in the study were formic acid
(pure for analysis grade) and bismuth(III) oxide
(highꢀpurity grade). The reaction of bismuth oxide
with formic acid was carried out in Teflon or glass vesꢀ
sels equipped with stirrers; the vessels were thermoꢀ
stated on WBꢀ2 water baths. The initial reagent ratio
was 10 g of Bi2O3 per 100 mL of HCOOH solution of
Chaplygina [4] in studying solubility in the normal
bismuth formate–formic acid system, discovered the forꢀ
mation of two compounds: Bi(HCOO)3 and BiOHCOO.
According to Stalhandske [5], tribismuth formate is a
layered polymeric structure that belongs to the trigonal
crystal system,
328 Å3
= 3. According to Aurivillius [6], the bismuth
oxoformate structure is built of double
R3m, a = 10.566 Å, c = 4.1193 Å, V =
,
Z
2+
IR peak frequencies (cm–1) for bismuth(III) formate, bisꢀ
muth oxoformate, and free formate ion
layers
Bi2O2
interlayered with formate ions. The crystal structure is
tetragonal, 4/nmm = 3.89 = 10.16
= 154 Å3
= 2. Bismuth oxoformate was also structurally studied
in [4, 7], where = 3.9145, = 33.58 Å [7]. Pisarevskii
P
,
a
Å,
c
Å,
V
,
Assignment
[13]
–
Bi(HCOOH) BiOHCOO [O CH] [13]
3
2
Z
a
c
2940 vw
2850 vw
1565 vs
1410 s
2820 w
2803
ν
CH
et al. [8] mentioned that the reported methods of bisꢀ
muth formate synthesis, which are based on the reacꢀ
tion of bismuth oxide or carbonate and metallic bisꢀ
muth with formic acid, do not provide any significant
bismuth formate yields because of its very low solubilꢀ
ity in formic acid. Pisarevskii et al. [8] proposed to
synthesize bismuth formate by reacting bismuth aceꢀ
tate with a 100ꢀfold excess of formic acid. The syntheꢀ
sis of precursor bismuth acetate uses acetic anhydride,
which is hard to obtain. Usually, bismuth formate is
prepared by crystallization from bismuth oxide soluꢀ
tions in formic acid by boiling and cooling the initial
solution [5, 6, 9]; the final bismuth product yield is not
high because of the low solubility of the oxide in forꢀ
mic acid. However, Anishchenko et al. [10] showed
the feasibility of preparing bismuth formate by a
solid–solution reaction as a result of treating 2 g of bisꢀ
1560 vs
–
1585
1383
1354
ν
as(CO )
2
δ
as(HCO)
s(CO )
1350 s
1380 w sh
1350 sh
1310 m
1290 w sh
1090 vw
760 m
ν
2
1100 vw
800 m
780 m
–
1060
700
π
(HCO )
2
δ
s(HCO)
550 m, br
–
ν(BiO)
Note: Band notations: s—strong; m—medium intensity; w—
weak; v—very; sh—shoulder; br—broad. Vibration notaꢀ
tions:
ν
—stretching;
δ
—bending; —outꢀofꢀplane.
π
564

INTERACTION OF BISMUTH(III) OXIDE
565
change (TG) curves were taken on an MOM derivatoꢀ
graph at a heating rate of 10 K/min. IR absorption
spectra (at 600–4000 cm–1) were recorded as tablets
with calcined KBr on a Specord IRꢀ75 spectrophoꢀ
tometer. Electron micrographs of products were
obtained with a Hitachi TM 1000 scanning electron
microscope.
c
Bi, g/L
10
9
8
BiOCOOH
7
6
5
4
3
2
1
Bi(COOH)3
Bismuth(III) macroamounts were determined by
titrating solutions with complexone III and Xylenol
Orange indicator; microamounts were determined
photocolorimetrically using sodium iodide [11]. Free
formic acid in bismuthꢀcontaining solutions was
determined by acid–base titration after masking bisꢀ
muth with complexone III [12]. Carbon and hydrogen
were determined by modified Pregl technique with
gravimetric endꢀpoint determination.
2
1
0
5
10
c
15
HCOOH, mol/L
20
25
RESULTS AND DISCUSSION
Fig. 1. Bismuth concentration in solution (g/L) versus iniꢀ
tial formic acid concentration (mol/L). Temperature С)
) 22 and ( ) 55.
Our study of the interaction of bismuth(III) oxide
with formic acid solutions of various concentrations at
22 1 and 55 2 С shows (Fig. 1) that the solubility
(
°
:
(1
2
°
curves comprise two branches. Along the ascending
branch, where the formic acid concentration increases
various concentrations. Mixtures were stirred for 4 h at
22 and 55 . The precipitate was filtered off
and dried in air.
from 0.55 to 3.3 mol/L at 22
tration in solution increases from 0.13 to 3.26 g/L,
respectively; at 55 as the acid concentration
°
С, the bismuth concenꢀ
1
2°С
°
С
Powder Xꢀray diffraction patterns of precipitation
products were measured on a Bruker powder diffractoꢀ
increases from 1.1 to 4.4 mol/L, the bismuth concenꢀ
tration in solution increases from 0.54 to 9.08 g/L,
respectively. As the formic acid concentration
meter (Cu
K radiation, counter rate: 0.1 deg/min).
α
Differential thermal analysis (DTA) and weightꢀ increases further, the bismuth concentration in soluꢀ
4
3
2
1
10
15
20
25
30
35
, deg
40
45
50
55
60
2θ
Fig. 2. Xꢀray diffraction patterns for (
1
) monoclinic bismuth oxide, (
is Bragg’s angle (deg).
2) bismuth oxide + bismuth oxoformate, (3) bismuth oxoꢀ
formate ( ), and ( ) bismuth formate.
3
4
θ
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 4 2012

566
MISHCHENKO et al.
10
μ
m
50 μm
(а)
(b)
100 μm
20 μm
(c)
(d)
Fig. 3. Micrographs of (a) the precursor bismuth oxide, (b) bismuth oxoformate, and (c, d) bismuth formates prepared at (c) 22
and (d) 55
°
С.
tion versus acid concentration curve passes through a oxoformate in the form of an individual compound
peak to reach 0.046 g/L at 22
(at 25 mol/L formic acid).
°
С
and 0.68 g/L at 55
°
С
(curve
obtained along the descending segment of the cBi
cHCOOH curve for = 11 and above feature diffraction
peaks ( : 5.28, 3.75, 3.04, 2.64, 2.15, 1.99 Å) intrinsic
3). Xꢀray diffraction patterns for the products
–
n
Xꢀray diffraction studies (Fig. 2) show that, along
the ascending segment of the cBi cHCOOH curve for the
ratio of formic acid to bismuth of 2.5–7.0, bismuth
d
–
to bismuth formate Bi(HCOO)3 [4, 5].
oxoformate of composition BiOCOOH is formed, and
along the descending segment of this curve for the obtained along the ascending segment of the cBi
The chemical composition of the precipitates
–
ratio of 11 and above, bismuth formate of composition cHCOOH curve verifies the formation of oxoformate of
Bi(HCOO)3 is formed. In the region of the peak, the composition BiOHCOO. The bismuth content (wt %)
precipitate is a mixture of basic and normal bismuth in the precipitate is 77.15 (calcd., 77.40); for carbon,
formates.
Thus, according to Xꢀray diffraction data, as the
formic acid concentration in solution increases, the
diffraction peaks ( : 4.06, 3.45, 3.24, 2.68, 2.38, 1.95
(curve )) intrinsic to monoclinic ꢀBi2O3 are reduced
in intensity [13]. New peaks appear in the diffraction
patterns ( : 9.98, 3.62, 3.05, 2.75, 2.65, 2.50 Å) which
4.36 (calcd., 4.45); and for hydrogen, 0.35 (calcd.,
0.37). Analyses of the precipitates obtained along the
descending segment of this curve indicate the formaꢀ
tion of formate Bi(COOH)3. The bismuth content
(wt %) is 60.86 (calcd., 60.74); for carbon, 10.45
(calcd., 10.47); and for hydrogen, 0.86 (calcd., 0.87).
d
Å
1
α
d
In the IR absorption spectrum of our synthesized
are assigned, according to [4, 6], to oxoformate BiOꢀ bismuth(III) formate, there are no bands belonging to
COOH; when
n
= 2.5–7.0, the precipitate is bismuth the vibrations of formic acid carboxyls at 1730 cm–1
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 4 2012

INTERACTION OF BISMUTH(III) OXIDE
567
[14, 15], but instead there are bands with the frequenꢀ
cies corresponding to the vibrations of the carboxylate
ion of the normal salt (table) [9, 14, 15]. In the formic
acid spectrum, very weak bands of the stretching vibraꢀ
tions of CH groups are masked by the strong absorpꢀ
tion of the carboxyl OH groups. They are hardly
noticeable in the spectrum of the salt. The fundamenꢀ
tal vibration frequencies in the spectrum of our preꢀ
pared bismuth(III) oxoformate (table) correspond to
reported data [9]. A characteristic feature of the specꢀ
trum is a relatively broad, mediumꢀintensity band with
a peak at 550 cm–1, which belongs to Bi–O stretching
vibrations [9]. The appearance in the spectra of bisꢀ
muth formates of the strongest bands of antisymmetric
νаs(СОО–) and symmetric νs(СОО–) stretching
modes of the carboxylate ion and the disappearance of
Δ
m, mg
Т
710
DTG
(а)
210
DТА
200
the
ν
(ОН) = 3400–3500 cm–1 stretching modes,
0
which appear in the initial formic acid and belong to
the carboxyl group, indicate the substitution of a bisꢀ
muthꢀcontaining cation for the carboxyl proton.
20
40
60
80
Electron micrographs show that the initial bismuth
TG
Т
oxide samples are particles with sizes up to 50
When bismuth(III) oxide is treated with formic acid
solution either at 22°C or at 55 , bismuth oxoforꢀ
µ
m (Fig. 3a).
°С
mate is first formed on the oxide surface. The oxoforꢀ
mate prepared at either temperature retains the
appearance of the initial bismuth oxide and consists of
DTG
820
730
platy crystals with sizes of 1.5–2
µ
m and ~0.1 m
µ
thick (Fig. 3b). The bismuth formate particles proꢀ
duced by the reaction of bismuth oxide with concenꢀ
trated formic acid solutions at 22
crystals ~10 m long and 1 m thick (Fig. 3c); at 55
bismuth formate is produced in the form of crystals
~100 m long and 20 m thick (Fig. 3d).
°
С are needleꢀshaped
(b)
DТА
µ
µ
°
С
µ
µ
Thermoanalytical measurements of bismuth forꢀ
mate in the linear heating mode in a helium atmoꢀ
sphere indicate a oneꢀstage decomposition reaction
210
270
(Fig. 4a). Intensive weight loss is observed at 200
and the reaction is accompanied by heat absorption. The
weight loss at the end of the reaction is = 77.9 mg.
°
С,
Δm
0
20
40
60
80
The calculated weight loss for metallic bismuth as the
final solid product is 78.51 mg. The DTA endotherm
at 270
bismuth (271.3
the formation of metallic bismuth with characteristic
peaks ( : 3.95, 3.28, 2.36, 2.27, 1.98, 1.97 Å [13]).
°С
corresponds to the melting point of metallic
TG
°
С). Powder Xꢀray diffraction verifies
d
Time
The thermoanalytical data obtained in the linear
heating mode for bismuth formate samples produced
by the reaction in air indicate the occurrence of a casꢀ
cade of consecutive endothermic and exothermic
stages and point to a possibility of preparing various
bismuth oxide phases upon their thermal decomposiꢀ
tion. Judging from the thermoanalytical curve, the iniꢀ
tially formed metallic bismuth then oxidizes even in
the course of the reaction (Fig. 4b). The weight loss
calculated for bismuth oxide as the final product is
64.56 mg, against the measured weight loss of 65.0 mg.
The two endotherms observed on the DTA curve corꢀ
Fig. 4. Thermoanalytical curves for bismuth(III) formate
and oxoformate in (a) an argon atmosphere and (b) air.
Sample size: 200 mg.
to highꢀtemperature faceꢀcentered cubic
endotherm at 730 ), which is stable up to the melting
temperature of the oxide at 824 (the endotherm in
the region of 810–850 ) [16]. Thermal annealing of
bismuth formate at 210 for 3 h yields metastable
ꢀBi2O3 bright yellow tetragonal ꢀBi2O3 with its characteristic
δ
ꢀBi2O3 (the
°С
°С
°
С
°
С
respond to the phase transition of monoclinic
α
β
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 4 2012

568
MISHCHENKO et al.
3. G. G. Briand and N. Burford, Chem. Rev. 56, 2601
diffraction peaks (
d
: 3.46, 3.19, 2.81, 2.73, 1.96, 1.93
for 4 h, it
ꢀBi2O3
Å
(1999).
[13]). When
β
ꢀBi2O3 is calcined at 350 С
°
transforms to lemonꢀyellow monoclinic
α
.
4. N. M. Chaplygina and L. S. Itkina, Zh. Neorg. Khim.
26, 3118 (1981).
5. C. I. Stalhandske, Acta Chem. Scand. 23, 1525 (1969).
In summary, for the reaction of bismuth oxide with
formic acid solutions, the solubility curve comprises
two branches. Bismuth oxoformate BiOCOOH is
6. B. Aurivillius, Acta Chem. Scand. 9, 1213 (1955).
formed along the ascending segment of the cBi–cHCOOH
7. F. Duan, Y. Zheng, L. Liv, et al., Mater. Lett. 64, 1566
(2010).
curve, and normal formate Bi(HCOO)3 is formed
along the descending segment of this curve. When bisꢀ
muth oxide is treated with 2.0 mol/L formic acid soluꢀ
tion with the acidꢀtoꢀoxide weight ratio of 10, bismuth
oxoformate is produced with final bismuth yield of
98.5%; when the acid concentration is 25.0 mol/L, the
product is normal formate with final bismuth yield of
99.4%. The thermal decomposition of bismuth forꢀ
mate in a helium atmosphere produces metallic bisꢀ
8. A. P. Pisarevskii, L. I. Martynenko, and N. G. Dzyubenko,
Zh. Neorg. Khim. 35, 1489 (1990).
9. G. Gattov and K. Sarter, Z. Anorg. Allg. Chem. 463
,
163 (1980).
10. N. I. Anishchenko, E. M. Panov, O. P. Syutkina, and
K. A. Kochetkov, Zh. Obshch. Khim. 49, 1185 (1979).
1 1 . P. P. K o r o s t y l e v, Photometric and Complexometric Analꢀ
ysis in Metallurgy (Handbook), Ed. by A.I. Busev (Meꢀ
tallurgiya, Moscow, 1984) [in Russian].
muth as a power; in air, tetragonal ( ) and monoclinic
β
(
α) bismuth oxides are produced.
12. E. A. Polyak, R. N. Musikhin, and L. A. Rodionova,
Zh. Anal. Khim. 25, 2447 (1970).
13. Powder Diffraction File (JCPDS ICDD, 1998).
14. I. Socrates, Infrared Characterictic Group Frequencies
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RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 4 2012