Synthesis, structure, and properties of V2O3(XO 4)2 (X = S, Se)

Article abstract of DOI:10.1134/S0036023610040042

Compounds described as V₂O₃(XO₄) ₂, where X = S or Se, were prepared from vanadium(V) oxide mixtures with concentrated sulfuric and selenic acids. The physicochemical properties of the products were studied; for V₂O₃(SeO₄) ₂, the crystal structure was determined by powder X-ray diffraction and neutron diffraction, and its key differences from the structure of V ₂O₃(SO₄)₂ were identified. V ₂O₃(SeO₄)₂ crystallizes in the monoclinic system with the unit cell parameters a = 15.3831(2)?, b = 5.54096(5)?, c = 9.71644(7)?, β = 111.886(1)°, V = 768.51?³, space group C2/c (no. 15).

Full text of DOI:10.1134/S0036023610040042

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2010, Vol. 55, No. 4, pp. 501–507. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © A.P. Tyutyunnik, V.N. Krasil’nikov, V.G. Zubkov, L.A. Perelyaeva, I.V. Baklanova, 2010, published in Zhurnal Neorganicheskoi Khimii, 2010, Vol. 55,
No. 4, pp. 554–560.
SYNTHESIS AND PROPERTIES
OF INORGANIC COMPOUNDS
Synthesis, Structure, and Properties
of V2O3(XO4)2 (X = S, Se)
A. P. Tyutyunnik, V. N. Krasil’nikov, V. G. Zubkov,
L. A. Perelyaeva, and I. V. Baklanova
Institute of SolidꢀState Chemistry, Ural Division, Russian Academy of Sciences,
ul. Pervomaiskaya 91, Yekaterinburg, 620219 Russia
Received November 20, 2008
Abstract—Compounds described as V2O3(XO4)2, where X = S or Se, were prepared from vanadium(V) oxide
mixtures with concentrated sulfuric and selenic acids. The physicochemical properties of the products were
studied; for V2O3(SeO4)2, the crystal structure was determined by powder Xꢀray diffraction and neutron difꢀ
fraction, and its key differences from the structure of V2O3(SO4)2 were identified. V2O3(SeO4)2 crystallizes in
the monoclinic system with the unit cell parameters
a
= 15.3831(2)
Å,
b
= 5.54096(5)
Å,
c
= 9.71644(7)
Å, β =
111.886(1) 2/ (no. 15).
°
,
V
= 768.51 Å3, space group
C c
DOI: 10.1134/S0036023610040042
Divanadium(V) trioxide disulfate V2O3(SO4)2 σ3 = 1410, Δσ = 1206; for the second one, σ1 = 247,
σ3 = 1330, Δσ = 1045) is apparently caused by some
difference between the local environments of vanaꢀ
dium atoms. The main purpose of this work was to
study the formation conditions, structures, and propꢀ
occupies a special place in the series of vanadium(V)
sulfate compounds [1–4]: M3VO2(SO4)2 (M = K, Rb,
Cs, Na), MVO2SO4 (M = K, Rb, Cs, Tl),
M4V2O3(SO4)4 (M = K, Rb, Cs, NH4), MVO(SO4)2
(M = K, Rb, Cs, Tl, NH4), K3VO(SO4)3,
M[VO2(SO4)(H2O)2] · H2O (M = K, Rb, Tl, NH4),
erties of V2O3(SeO4)2
.
M[VO2(SO4)(H2O)2]
(M
=
Cs,
NH4),
EXPERIMENTAL
M0.67Na0.33[VO2(SO4)(H2O)2] (M = K, Rb, Cs, NH4),
K[VO2(SO4)(H2O)], and V2O3(SO4)2. This is due to feaꢀ
tures of its crystal structure [5] formed from pairs of
vanadium atoms linked to each other by both an oxyꢀ
gen bridge and two SO4 bridges, while the other sulfate
groups are incorporated into the lattice by binding the
The most facile method for the synthesis of
V2O3(SeO4)2 was thermal treatment of a mixture of
specialꢀpurity grade V2O5 and chemical grade H2SeO4
in a platinum cup for 8 h with intermediate trituration
and addition of concentrated selenic acid. The formaꢀ
tion of the desired product at 200–220
by the overall reaction
V2O5 + 2H2SeO4 = V2O3(SeO4)2 + 2H2O.
°
С is described
V2O34+
cations to one another [5]. It is quite probable
that divanadium(V) trioxide diselenate V2O3(SeO4)2
(1)
would have a similar structure [3, 4]. According to 77Se
NMR spectroscopy [6], SeO4 groups occupy nonꢀ
equivalent positions in the crystal structure of
V2O3(SeO4)2. Some of them can be arranged in the
equatorial plane of the VO6 octahedra perpendicular to
the direction of the V–O multiple bond, and the other
are directed opposite to this bond. Analysis of the 51V
NMR spectra of V2O3(XO4)2 (X = S, Se) has shown
[3, 6] that vanadium atoms in both crystal structures
have similar types of local environment. The 51V NMR
spectra are characterized by the axial anisotropy of the
chemical shift tensor, which is indicative of the octaꢀ
hedral environment of vanadium in the crystal strucꢀ
tures of V2O3(SO4)2 and V2O3(SeO4)2 and is consistent
with Xꢀray diffraction data [5]. However, the observed
difference between the anisotropy parameters of the
chemical shift tensor [6] (for the first one, σ1 = 204,
The conditions for the stabilization of the sample
weight and the completion of reaction (1) were deterꢀ
mined by thermogravimetric and chemical analysis.
The alternative procedure for the synthesis of
V2O3(SeO4)2 included the dissolution of V2O5
concentrated selenic acid followed by evaporation,
drying of the precipitate, and maintaining it at 200
⋅
nH2O in
°С
for 8 h. V2O3(SO4)2 was synthesized in a similar way.
The completion of the reactions and the purity of
products were checked by means of a POLAM Cꢀ112
optical polarization microscope with optical immerꢀ
sion control technique and by Xꢀray diffraction. The
Xꢀray diffraction patterns were measured using Cu
K
α
1
radiation on a STADIꢀP automated diffractometer
equipped with miniꢀPSD in the transmission geomeꢀ
try with scan steps of
from to 120 . Polycrystalline silicon (
was used as the external standard. The possible impuꢀ
Δ2θ
= 0.02
°
in the
2θ
angle range
2°
°
a
= 5.43075(5) Å)
501

502
TYUTYUNNIK et al.
102, Å2) of atꢀ
Table 1. Coordinates and thermal parameters (
oms in the structure of V2O3(SeO4)2
×
and thermal factors are presented in Table 1. Table 2
gives the interatomic distances and bond angles. IR
absorption spectra were recorded on a Vertex specꢀ
trometer (Bruker) in the range of 1200–400 cm–1 for
powder samples (mineral oil mulls) at room temperaꢀ
ture. Raman spectra were measured on a RAMII
attachment compatible with the Vertex 70 IR Bruker
Atom
x
/
a
y
/
b
z
/c
Uiso/Ueq
Se
V
0.3544(1) 0.8701(3) 0.9019(1) 1.36(4)
0.3785(2) 0.4120(4) 0.7086(3) 1.82(8)
0.4101(2) 0.1011(8) 0.8783(4) 1.47(9)
0.2461(2) 0.8534(9) 0.7792(3) 1.29(8)
0.4057(2) 0.6181(9) 0.8845(3) 1.29(9)
0.3516(2) 0.8694(9) 0.0701(3) 1.33(8)
0.3481(2) 0.613(1) 0.5876(3) 1.91(9)
O(1)
O(2)
O(3)
O(4)
O(5)
O(6)
spectrometer (
λ
= 1064 nm). Thermogravimetric
studies were carried out on a Qꢀ1500D derivatograph
at a heating rate of 10 K/min in air. The amount of
vanadium in the samples was determined titrimetriꢀ
cally [9]. Sulfur and selenium were quantified by therꢀ
mogravimetry. Elemental analysis was carried out by
standard procedures.
0
0.111(1) 1/4
Rp, %
F2), %
1.80
1.50
1.3(1)
wRp, %
2.30
R(
Xꢀray
4.70
3.98
RESULTS AND DISCUSSION
Neutrons 1.93
The V2O3(SO4)2 and V2O3(SeO4)2 powders are
orangeꢀyellow and yellow colored, respectively. A
microscopic examination shows wellꢀshaped prisꢀ
matic crystals of V2O3(SO4)2 as combinations of three
pinacoids, (100), (010), and (001), and a rhombic
Table 2. Interatomic distances (
structure of V2O3(SeO4)2
d
) and bond angles (ω) in the
prism (110). The basal plane (001) forms a
β
angle of
Bond , Å
d
Angle
ω
, deg
104.5° with the principal section axis ( ). The crystal
extinction is usually inclined, but sections with
straight extinction are also encountered. The refracꢀ
c
Se–O1
1.603(4)
1.651(3)
1.643(5)
1.652(3)
O2–V–O3
O2–V–O4
O2–V–O5
O2–V–O6
O3–V–O4
O3–V–O5
O3–V–O6
O4–V–O5
O4–V–O6
O5–V–O6
V–O(6)–V
86.6(2)
87.2(2)
97.9(2)
159.5(2)
164.0(2)
98.5(2)
88.8(2)
96.9(2)
91.9(2)
102.5(2)
171.8(4)
Se–O2
Se–O3
Se–O4
tion parameters are as follows: Ng ӷ 1.785 (dark yelꢀ
low), Nm > 1.785 (yellow), Np = 1.760 (light yellow).
The sample of V2O3(SeO4)2 powder looked mainly as
irregularly shaped grains with irregular extinction;
however, often encountered were also relatively large
plate crystals and their fragments with straight extincꢀ
tion relative to the extension and weak pleochroism
with color changing from yellow (Ng) to light yellow
Se–O average 1.637/1.63
V–O1
V–O2
V–O3
V–O4
V–O5
V–O6
2.308(4)
1.991(4)
1.966(4)
2.000(5)
1.558(5)
1.764(3)
(
Np). The refractive and birefringence indices (Ng
=
Np) are very high, Np > 1.785.
According to Xꢀray diffraction data (Fig. 1) [5], the
crystal structure of V2O3(SO4)2 is composed of pairs of
highly distorted VO6 octahedra connected to one
another by a bridging O atom and two SO4 tetrahedra
where all O atoms are coordinated to vanadium (Fig. 1a),
The V–O bond length in the V–O–V bridge is 1.780 Å
V–O average 1.931/1.89
rity phases were identified using the Powder Diffracꢀ
tion Database ICDD PDF2 (ICDD, USA, Release
2007). The neutron diffraction studies were carried out
on a D7A setup of the IVV 2M reactor (manufactured
in the town of Zarechnyi). The neutron diffraction
and the bond angle is 148.4
neighboring vanadium atoms is comparable to that
estimated for Cs4V2O3(SO4)4 (3.512 [10], being
equal to 3.426 Å. The distortion of the VO6 octahedra is
due to the presence of a very short V–O bond (1.565
in each of them. V2O3(SO4)2 crystallizes in the monoꢀ
clinic system with the unit cell parameters = 9.472
= 8.913 = 9.891 = 104.56 = 4, space group
21/ . The Xꢀray diffraction patterns of V2O3(SeO4)2
were indexed (Fig. 2) in the monoclinic system with
the unit cell parameters = 15.3831(2)
5.54096(5) = 9.71644(7) = 111.886(1)
= 768.51 Å3, space group
. The structure of
°. The distance between the
Å)
patterns were recorded in the
2θ
angle range from
5°
λ
to
=
Å)
135 with a step of 0.05° at the neutron wavelength
°
1.5302 Å. The crystal structures were solved and
refined using simultaneously neutron and Xꢀray difꢀ
fraction data and EXPO and GSAS software [7, 8].
The line profile was fitted by the pseudoꢀVoigt funcꢀ
a
Å,
b
Å,
c
Å,
β
°, Z
P
a
tion
I(2
θ)
=
η
L(2θ)
+
(1 –
η
)G
(2 ), where L and G are
θ
a
Å, b =
the Lorentzian and Gaussian functions, respectively,
and the angular dependence of the line width was fitꢀ
ted by the relation
where FWHM is the full width at half maximum. The
background level was specified as a combination of fifꢀ
teen Chebyshev polynomials. The atom coordinates
Å,
c
Å,
β
°
,
(
FWHM)2 =
U
tan2
θ
+
V
tan + W,
θ
V
C2/c
V2O3(SeO4)2 differs from the structure of V2O3(SO4)2
,
although it is also formed by isolated pairs of highly
distorted VO6 octahedra containing a short V–O bond
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 4 2010

SYNTHESIS, STRUCTURE, AND PROPERTIES
503
(а)
O(9)
S(1)
O(8)
S(1)
O(11)
O(1)
S(2)
O(9)
O(10)
V(1)
S(1)
V(2)
O(6)
O(4)
O(3)
O(7)
O(5)
O(2)
S(2)
O(4)
S(2)
O(5)
(b)
Se
Se
Se
O(1)
O(4)
O(3)
O(5)
Se
O(6)
Se
O(2)
O(2)
V
V
O(4)
O(1)
Se
O(5)
O(3)
Se
Se
Fig. 1. Structure of isolated pairs of highly distorted VO octahedra in (a) V O (SO ) and (b) V O (SeO ) .
4 2
6
2
3
4 2
2
3
4+ cation. In
V2O3
and SeO4 groups; the vanadium atoms are joined in
pairs only by oxygen bridges. The
2− ions connect
sponding to the V–O–V bridge in the
the Raman spectrum, this mode is shifted to lower freꢀ
quencies and occurs at 750 cm–1. The position of the
band at 1011 cm–1 (Raman) is close to the stretching
bands for the vanadium–oxygen multiple bonds in the
IR spectrum of V2O5 (1020 cm–1), VOBr3 (1025 cm–1),
and VOCl3 (1035 cm–1) [11, 12]. The symmetric
stretching (ν1) mode of the sulfate ion is manifested as
a narrow intense band at 1025 cm–1 (IR and Raman).
SeO4
to each other to form
4+
the oxovanadium groups
V2O3
an infinite threeꢀdimensional network (Fig. 3). The
structural and thermal parameters of V2O3(SeO4)2 are
summarized in Table 1 and the interatomic distance
and bond angles are in Table 2. The V–O interatomic
distances in the V–O–V bridge are 1.764(3) Å, the
4+
VOV bond angle in the
oxocation is 171.8(4) ,
°
V2O3
and the short terminal V–O bond in the VO6 octaheꢀ
dron is 1.558(5) Å.
A set of fairly intense IR bands in the range of 1215–
2−
1055 cm–1 is due to the ν3 mode of
Attention is
SO4 .
drawn by splitting of the bending modes ν2 and ν4
caused by removal of mode degeneracy upon decrease
in the local symmetry of the SO4 tetrahedron in the
V2O3(SO4)2 lattice and resonance interactions [13].
The structural features of the compounds are
reflected in their vibrational spectra. The IR spectrum
of V2O3(SO4)2 (Table 3) exhibits a strong, rather broad
band at 790 cm–1 (at 795 cm–1 for the seꢀlenate) correꢀ
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 4 2010

504
TYUTYUNNIK et al.
I
(а)
10
20
30
40
50
60
70
80
90
100
110
120
, deg
(b)
2θ
I
0
20
40
60
80
100
120
, deg
2θ
Fig. 2. Experimental, theoretical, and difference diffraction patterns of V O (SeO ) : (a) neutron diffraction; (b) Xꢀray diffraction.
2
3
4 2
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 4 2010

SYNTHESIS, STRUCTURE, AND PROPERTIES
505
c
b
a
Fig. 3. Schematic view of the crystal structure of V O (SeO ) . The selenium atoms are located in tetrahedra and the vanadium
2
3
4 2
atoms are in octahedra.
(a)
(b)
1100 1000 900 800 700 600 500 400 300 200 100
Δν, cm–1
1200 1100 1000 900 800 700 600 500 400
, cm–1
ν
Fig. 4. (a) IR and (b) Raman spectra of V O (SеO ) .
4 2
2
3
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 4 2010

506
TYUTYUNNIK et al.
Table 3. Assignment of IR and Raman bands for V2O3(XO4)2 (X = S, Se)
V O (SO )
V O (SeO )
4 2
2
3
4 2
2
3
Assignment
Assignment
IR
Raman
1218
IR
Raman
ν3(SO24–
)
1215
1170
1145
1090
1055
1025
1066
1052
1025
ν1(SO24–
ν
(V=O)
)
1010
1011
1010
932
918
888
846
1010
ν
(V=O)
ν3(SeO24–
)
909
892
863
851
801
ν1(SeO24–
ν
(V–O–V)
)
790
660
750
ν
(V–O–V)
795
775
688
ν4(SO24–
)
645
630
610
520
609
535
525
ν
(V–O–SO )
522
498
ν
(V–O–SeO )
3
3
499
495
475
δ
(V–O–V)
ν2(SO24–
)
475
ν4(SeO24–
ν2(SeO24–
)
)
450
458
401
436
386
339
300
230
340
315
285
222
Lattice vibrations
Lattice vibrations
All oxygen atoms of the sulfate ligands are coordiꢀ coordination of the selenate ion induces nonꢀequivaꢀ
nated by vanadium, and the sulfur–oxygen bond lence of the Se–O bonds, resulting in symmetry
lengths are differentiated. In the case of the selenate
ion, the degree of coordination of oxygen atoms of
decrease to С2 or even lower. Splitting of the inner
modes should give rise to 8 IR bands and 9 Raman
ν
vanadium is lower (Fig. 3). The uncoordinated Td
ꢀ
bands; this is really so in the experiment (Table 3). The
2−
SeO4
2−
SeO4 ,
symmetric selenate ion
has four inner vibraꢀ
asymmetric stretching mode (ν3) of
is shifted to
tions: the stretching modes ν1
875 cm–1 and the bending modes ν2
ν4 Т2
= 432 cm–1 [13, 14]. The fully symmetric ν1
vibration, like the ν2 vibration of the metalꢀuncoꢀ
(
А1
)
= 833 and ν3
= 335 and
(А1)
(Т2) =
lower frequency relative to this band of the sulfate
(935–850 cm–1, Fig. 4); this allows assigning the narꢀ
row intense band at 1010 cm–1 to vibrations of the
short V–O bonds of the VO6 octahedron and confirms
the assignment of a similar band in the IR spectrum of
V2O3(SO4)2. The vanadium coordination led to a
(Е)
(
)
(E)
ordinated selenate ion, is Raman active, whereas the
other modes are both IRꢀ and Ramanꢀactive. The
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 4 2010

SYNTHESIS, STRUCTURE, AND PROPERTIES
507
decrease in the frequency of the fully symmetrical fied. This explains the previously observed [3, 6] difꢀ
stretching mode ν1(А1) and an increase in the ν2(Е)
freꢀ ference in the parameters of the 51V NMR spectra of
quency to 400–386 cm–1 in the selenate ion (Table 3).
The vibrations of the bridging oxygen atoms of the
these compounds. The presence of VO6 octahedra
containing a short V–O bond in the V2O3(XO4)2 strucꢀ
ture is in line with the axial symmetry of the chemical
shift tensor, while the difference in the tensor parameꢀ
ters is apparently caused by the type of distortion of
VO6 octahedra. The IR and Raman spectra reflect the
structural features of the compounds; the spectra of both
compounds contain a vibrational mode at 1010 cm–1
corresponding to the short V–O bond in the VO6 octaꢀ
hedron.
corner V–O–Se bonds having V–O distances of ~2
Å
probably give rise to 522–498 cm–1 modes. The asymꢀ
metric bending mode (ν4) of the selenate ion occurs at
458 (IR) and 436 cm–1 (Raman). Below 340 cm–1, the
bending and translation modes of the crystal modes
are manifested. In the spectral region containing
vibrations of the highly distorted VO6 octahedra and
the V–O–V bridge, no significant differences were
found between the sulfate and the selenate. This is in
good agreement with the 51V NMR data indicating
similarity of the local environments of vanadium in
both structures [6].
ACKNOWLEDGMENTS
The authors are grateful to V. A. Volkovich for techꢀ
nical assistance in recording the Raman spectra at the
Chair of Rare Metals and Nanomaterials of the Physiꢀ
coꢀTechnical Department of the Ural State Technical
University USTUꢀUPI.
This work was supported by a Presidential Grant
for Support of Leading Scientific Schools (Nshꢀ
1170.2008.3).
Thermal decomposition of V2O3(SO4)2 with SO3
evolution becomes noticeable at ~400
two stages, which are manifested by anomalous points
in the DTA curve at 578°C and 635 and a break in
°С and includes
°С
the TG curve observed after elimination of approxiꢀ
mately one mole of sulfur trioxide. The anomalous
point in the DTA curve at 578°С corresponds apparꢀ
ently to the formation of an intermediate compound
with a lower content of bound SO3. However, we could
not isolate and identify this compound as the samples
obtained by annealing of V2O3(SO4)2 in the temperaꢀ
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°
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↑,
(3)
(4)
V2O3(SO4)2 + M3VO4 = 3MVO2SO4.
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occurs much more slowly; in addition, the formation
of MVO2SeO4 competes with its decomposition:
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MVO2SeO4 = MVO3 + SeO2 + 1/2O2.
(5) 12. R. Enjalbert and J. Galy, Acta Crystallogr., Sect. C 42
(11), 1467 (1986).
The needle crystals of selenium dioxide (No > 1.785)
formed by reactions (2) and (5) are deposited on cool
parts of the reactor.
13. K. Nakamoto, Infrared and Raman Spectra of Inorganic
and Coordination Compounds, 5th Ed. (Wiley, New
York, 1997).
Thus, a considerable difference between the crystal
structures of V2O3(SеO4)2 and V2O3(SO4)2 was identiꢀ
14. J. Hanuza, M. Maczka, J. Lorenc, et al., Spectrochim.
Acta A 71, 68 (2007).
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