Synthesis, crystal structure, and vibrational spectra of M 4V2O3(SO4)4 (M = K, Rb, Cs)

Article abstract of DOI:10.1134/S0036023611040152

Synthesis was performed and physicochemical properties were studied for the M₄V₂O₃(SO₄)₄ complexes, where M = K, Rb, or Cs. Their crystal structures were determined using the set of data from X-ray diffraction and neutron diffraction studies. All compounds crystallize in a triclinic lattice (space group P1, Z = 2) with the parameters: a = 7.7688(2), 7.8487(1), 8.1234(1) ?; b = 10.4918(3), 10.8750(2), 11.1065(1) ?; c = 11.9783(4), 12.1336(2), and 11.8039(1) ?; α = 76.600(2)°, 77.910(1)°, 79.589(1)°; β = 75.133(2)°, 75.718(1)°, 87.939(1)°; γ = 71.285(2)°, 72.189(1)°, 75.567(1)°; V = 881.78(5), 945.42(3), 1014.34(2) ?³ for K, Rb, Cs, respectively. The structure of M₄V₂O ₃(SO₄)₄ was found to be formed by discrete complex anions V₂O₃(SO₄) ₄ ^4- incorporating two oxygen-bridged vanadium atoms in a distorted octahedral oxygen environment. The sulfate groups are coordinated by the vanadium atoms in the chelating mode with a large scatter of S-O interatomic distances and OSO angles. Every VO₆ octahedron has a short terminal vanadium-oxygen bond with a length of about 1.6?. The V₂O ₃(SO₄) ₄ ^4- complex anions in potassium and rubidium compounds differ from that in Cs₄V ₂O₃(SO₄)₄ in the type of symmetry and mutual spatial orientation. The vibrational spectra were presented and interpreted in line with the structural analysis data.

Full text of DOI:10.1134/S0036023611040152

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2011, Vol. 56, No. 4, pp. 491–500. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © V.N. Krasil’nikov, A.P. Tyutyunnik, V.G. Zubkov, I.F. Berger, L.Ya. Perelyaeva, I.V. Baklanova, 2011, published in Zhurnal Neorganicheskoi Khimii,
2011, Vol. 56, No. 4, pp. 531–540.
SYNTHESIS AND PROPERTIES
OF INORGANIC COMPOUNDS
Synthesis, Crystal Structure, and Vibrational Spectra
of M4V2O3(SO4)4 (M = K, Rb, Cs)
V. N. Krasil’nikov, A. P. Tyutyunnik, V. G. Zubkov, I. F. Berger,
L. Ya. Perelyaeva, and I. V. Baklanova
Institute of SolidꢀState Chemistry, Ural Branch, Russian Academy of Sciences,
ul. Pervomaiskaya 91, Yekaterinburg, 620219 Russia
Received July 15, 2009.
Abstract—Synthesis was performed and physicochemical properties were studied for the M4V2O3(SO4)4
complexes, where M = K, Rb, or Cs. Their crystal structures were determined using the set of data from Xꢀ
ray diffraction and neutron diffraction studies. All compounds crystallize in a triclinic lattice (space group
P1,
= 10.4918(3), 10.8750(2), 11.1065(1) Å
= 76.600(2)°, 77.910(1)°, 79.589(1)°; = 75.133(2)°,
= 881.78(5), 945.42(3), 1014.34(2) Å3 for
Z
c
= 2) with the parameters:
= 11.9783(4), 12.1336(2), and 11.8039(1) Å;
a
= 7.7688(2), 7.8487(1), 8.1234(1) Å
;
b
;
α
β
75.718(1)°, 87.939(1)°;
γ
= 71.285(2)°, 72.189(1)°, 75.567(1)°; V
K, Rb, Cs, respectively. The structure of M4V2O3(SO4)4 was found to be formed by discrete complex anions
4− incorporating two oxygenꢀbridged vanadium atoms in a distorted octahedral oxygen environꢀ
V2O3
(
SO4
)
ment. The s4ulfate groups are coordinated by the vanadium atoms in the chelating mode with a large scatter
of S–O interatomic distances and OSO angles. Every VO6 octahedron has a short terminal vanadium–oxygen
bond with a length of about 1.6 Å. The
4− complex anions in potassium and rubidium compounds
V2O3
(
SO4
)
4
differ from that in Cs4V2O3(SO4)4 in the type of symmetry and mutual spatial orientation. The vibrational
spectra were presented and interpreted in line with the structural analysis data.
DOI: 10.1134/S0036023611040152
Study of the chemical nature and structure of the ions, each of them comprising a pair of distorted VO6
active component of vanadium catalysts for sulfur
dioxide conversion is necessary for the understanding
of the conversion mechanism [1–6]. In this connecꢀ
tion, attention is focused on the investigation of sysꢀ
tems that model the active component under condiꢀ
tion of their practical use, in particular, of ternary
oxide systems, M2O–V2O5–SO3 (M is alkali metal
except for lithium). The studies of phase relations in
these systems revealed four main types of compounds,
alkali metal oxovanadium(V) sulfates [7–9]:
M3VO2(SO4)2 (I), MVO2SO4 (II), M4V2O3(SO4)4 (III),
and MVO(SO4)2 (IV), where M = K, Rb, Cs. Comꢀ
pounds of types II and III refer to quasibinary systems,
M2S2O7–V2O5; studies of the melting diagrams of these
systems [10–12] showed that M4V2O3(SO4)4 melt
without decomposition and can be isolated as single
crystals on slow cooling of the melt. According to
51V NMR data, vanadium in the structure of
M4V2O3(SO4)4 has a distorted octahedral oxygen enviꢀ
ronment, as indicated by the axial anisotropy of the
chemical shift tensor [3]. To date, in the M4V2O3(SO4)4
series, the crystal structure of Cs4V2O3(SO4)4 has been
octahedra linked by an oxygen bridge. The sulfate
groups are coordinated by vanadium in the bidentate
chelating mode. Since no structural data for potassium
and rubidium compounds are available from the literꢀ
ature, the main goal of this study was the synthesis and
physicochemical and structural study of M4V2O3(SO4)4
(M = K, Rb, Cs) by vibrational spectroscopy and powꢀ
der Xꢀray diffraction and neutron diffraction.
EXPERIMENTAL
The compounds M4V2O3(SO4)4 (M = K, Rb, Cs)
were synthesized by two procedures based on the folꢀ
lowing reactions:
2K2S2O7 + V2O5 = K4V2O3(SO4)4,
(1)
(2)
4MHSO4 + V2O5 = M4V2O3(SO4)4 + 2H2O.
Reaction (2) was used for the synthesis of rubidium
and cesium compounds as no commercial disulfates of
these elements were available and their synthesis in the
pure state by thermolysis of MHSO4 was very laborꢀ
intensive [14]. Potassium disulfate needed to carry out
reaction (1) was prepared by thermolysis of K2S2O8
(pure for analysis grade). The synthesis of MHSO4 was
performed by dissolution of special purity grade
studied by singleꢀcrystal Xꢀray diffraction analysis
[13]. The available data indicate that the compound
4−
structure is composed of the
complex
,
V O SO
4
4
(
)
2
3
491

492
KRASIL’NIKOV et al.
M2CO3 in dilute H2SO4 (pure for analysis grade) folꢀ extended in the direction parallel to the optical indicꢀ
atrix Ng. An important feature of the crystals that facilꢀ
itates the diagnostics is pleochroism. The refractive
indices measured by the immersion method are as folꢀ
lowed by evaporation of the solution until hydrogen
sulfate crystals formed. The reactant mixtures were
thoroughly milled in agate mortars and annealed in
lows: K4V2O3(SO4)4 – Ng = 1.785 (orangeꢀred), Nm
=
platinum crucibles at 200–380 C for 30 h. In order to
°
1.683 (yellow), Np 1.560 (light yellow);
=
accelerate the formation of individual M4V2O3(SO4)4
phases, intermediate milling of the samples was carꢀ
ried out every 5 h of annealing.
Rb4V2O3(SO4)4 – Ng = 1.762 (orange), Nm = 1.667
(light yellow), Np = 1.569 (colorless); Cs4V2O3(SO4)4 –
Ng = 1.781 (light yellow), Np = 1.584 (colorless).
Melting of M4V2O3(SO4)4 occurs without decomꢀ
The completion of the reaction and the purity of
synthesis products were monitored using the POLAM
Sꢀ112 transmittedꢀlight polarizing microscope and by
diffraction techniques. The IR absorption spectra
were measured on a Vertex 80 Bruker FT IR spectromꢀ
eter in the range of 200–4000 cm–1 for powdered samꢀ
ples (pellets in CsI), the Raman spectra were recorded
position at temperatures of 395
°
С (K), 416 С (Rb),
°
412 (Cs). On superheating by approximately 50 С
°С
°
above the melting points, the M4V2O3(SO4)4 melts start
to release sulfur dioxide to the gas phase. The potasꢀ
sium compound is the least stable in this series. On fast
cooling of the melt, it readily transforms to a glassy
phase. The melting points of M4V2O3(SO4)4, which we
determined by visual polythermy, are in good agreeꢀ
ment with the results of an earlier integrated study of the
melting diagrams of M2S2O7–V2O5 quasibinary sysꢀ
on a RENISHAWꢀ1000 spectrometer (Ar+ laser,
λ
=
514.5 nm). The thermal properties were studied using
a Qꢀ1500D derivatograph and a MINꢀ8 polarization
microscope equipped with a thermal attachment [7].
In all experiments, hygroscopic properties of the comꢀ
pounds were taken into account and measures were
taken to minimize the effect of atmospheric moisture.
tems: 398°С (K), 414°С
(Rb), and 412 С (Cs) [10–12].
°
The hygroscopic properties of M4V2O3(SO4)4 menꢀ
tioned above are due to the reaction of the compounds
Xꢀray diffraction patterns were measured in a with water vapor given by
K radiation on a STADIꢀP automated diffractoꢀ
1
Cu
α
M V O SO + 7H2O
(
)
4
4
4
2
3
meter equipped with miniꢀPSD in the transmission
geometry at the scanning step = 0.02 in the range
of angles = 2 –120 . Polycrystalline silicon was
used as the external standard ( = 5.43075(5) Å). The
(3)
(4)
Δ2θ
°
= 2M VO SO H O ⋅ H O + 2MHSO ,
4 )(
(
)
]
[
2
2
2
4
2
2θ
°
°
Cs V O SO + 5H2O
(
)
4
4
4
2
3
a
possible impurity phases were identified using the
International Centre for Diffraction Data Powder Difꢀ
fraction File ICDD PDF2 (ICDD, USA, Release
2007). The neutron diffraction patterns were recorded
at room temperature on a D7A facility of the IVV 2M
= 2Cs VO SO H O + 2CsHSO .
4 )(
(
)
]
[
2
2
4
2
Under water vapor saturated at room temperaꢀ
ture (storage in a closed desiccator above water),
reactions (3) and (4) are very fast [17, 18]. Hydraꢀ
tion of potassium and rubidium compounds gives
reactor (town of Zarechnyi) in the range of angles
2θ
=
M[VO2(SO4)(H2O)2] H2O trihydrates having intensive
⋅
5°
–135 at a step of 0.05 and neutron wavelength
°
°
λ
=
yellow color [17] and colorless hydrogen sulfates. The
products can easily be distinguished from each other
under a microscope. The hydration of Cs4V2O3(SO4)4
gives, apart from the colorless cesium hydrogen sulꢀ
fate, the orange dihydrate Cs[VO2(SO4)(H2O)2], which
crystallizes as very thin fibers [18].
1.532 Å. The crystal structures of the compounds were
solved and refined using both the Xꢀray and neutron
diffraction data by the EXPO and GSAS programs
[15, 16]. The line profile was fitted by the pseudoꢀVoigt
function:
I(2θ)
=
η*
L
(2
θ)
+
(1 –
η)*
G
(2 ) (L and G are
θ
the Lorentz and Gauss functions, respectively), the
angular dependence of the line width was approximated
The powder Xꢀray diffraction patterns of
M4V2O3(SO4)4 (M = K, Rb, Cs) were indexed in terms
by the expression:
(
FWHM)2 =
U
tan2
θ
+
V
tan + W,
θ
of the triclinic lattice (space group
Z = 2) (Table 1).
P1,
where FWHM is the full line width at half maximum.
The background level was fitted by a combination of
fifteen Chebyshev polynomials.
Since the unit cell parameters Cs4V2O3(SO4)4 are in
good agreement with the data obtained for single crysꢀ
tals [10], the latter was used as the initial model to
refine the structure of the compound Cs4V2O3(SO4)4 we
obtained. However, this model does not describe the
structures of the potassium and rubidium compounds;
therefore, the atom coordinates for M4V2O3(SO4)4
(M = K, Rb) were determined by a direct method
using the EXPO program [15]. For convenience of the
discussion, the vanadium, sulfur, and oxygen atoms
are numbered according to [10]. The final model
refinement for all compounds was performed using
RESULTS AND DISCUSSION
The properties of potassium and rubidium comꢀ
pounds in the M4V2O3(SO4)4 series are closely similar.
The powdered potassium compound is orangeꢀyellow,
the rubidium compound is orange, and cesium comꢀ
pound is bright light yellow. All M4V2O3(SO4)4 comꢀ
pounds tend to form crystals as irregularly shaped
grains or plates with poorly developed cleavage slightly both Xꢀray diffraction and neutron diffraction data
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 4 2011

SYNTHESIS, CRYSTAL STRUCTURE, AND VIBRATIONAL SPECTRA
493
Table 1. Structural data for M4V2O3(SO4)4 (M = K, Rb, Cs)
K
Rb
Cs
Space group
P1
P1
P1
The number of formula units
,
Z
2
2
2
a
,
Å
Å
Å
7.7688(2)
10.4918(3)
11.9783(4)
76.600(2)
75.133(2)
71.285(2)
881.78(5)
2.11/1.62
1.88/1.49
4.52
7.8487(1)
10.8750(2)
12.1336(2)
77.910(1)
75.718(1)
72.189(1)
945.42(3)
1.75/1.33
1.99/1.57
2.72
8.1234(1)
11.1065(1)
11.8039(1)
79.589(1)
87.939(1)
75.567(1)
1014.34(2)
1.91/1.49
2.27/1.81
3.71
b
,
c
,
α
, deg
, deg
, deg
Å3
wRp Rp, %
β
γ
V
,
/
Xꢀrays
Neutrons
Xꢀrays
R
(
F2), %
Neutrons
3.30
4.37
3.36
CHI2
1.155
1.330
1.285
and the GSAS program package [16]. The results of out generally using only our data. The structural
our structure refinement for Cs4V2O3(SO4)4 coincide
with published data [10] to within the standard deviaꢀ
parameters, the atom coordinates and isotropic therꢀ
mal parameters, and the shortest interatomic disꢀ
tions. Therefore, the subsequent discussion is carried tances and bond angles are summarized in Tables 1–5.
(а)
(b)
(c)
O(17)
O(14)
O(14)
O(17)
O(17)
O(18)
O(14)
O(18)
S(3)
O(18)
O(12)
S(1)
O(12)
O(11)
V(2)
O(12)
O(3)
V(1)
O(3)
V(1)
O(11)
O(3)
S(3)
S(1)
S(1)
S(3)
O(11)
O(16)
O(16)
O(5)
O(8)
O(6)
S(2)
V(2)
O(8)
O(6)
O(8)
O(6)
O(5)
O(1)
S(4)
O(5)
O(1)
S(4)
O(16)
V(2)
O(19)
O(10)
O(1)
O(19)
O(10)
V(1)
O(4)
S(4)
O(19)
O(10)
S(2)
S(2)
O(4)
O(2)
O(2)
O(4)
O(9)
O(15)
O(9)
O(15)
O(2)
O(7)
O(9)
O(15)
O(7)
O(7)
O(13)
O(13)
O(13)
(d)
(e)
(f)
O(14)
O(14)
O(19)
O(19)
O(14)
O(19)
O(15)
S(3)
O(18)
O(8)
S(3)
V(1)
S(3)
O(18)
O(15)
O(15)
V(1)
O(16)
O(18)
V(1)
O(16)
O(3)
O(2)
S(2)
O(1)
O(3)
O(2)
S(2)
O(1)
S(4)
O(2)
O(3)
O(7)
O(4)
O(4)
O(4)
S(4)
S(1)
S(2)
O(5)
O(16)
O(7)
O(7)
S(4)
O(9)
O(11)
O(9)
O(17)
O(9)
O(11)
O(6)
O(6)
O(6)
V(2)
O(10)
O(12)
S(1)
O(12)
S(1)
O(13)
V(2)
O(10)
O(13)
V(2)
O(15)
O(12)
O(13)
O(1)
O(11)
O(10)
O(17)
O(17)
4−
4
Fig. 1. View of the structure of the
(
)
complex ion for (a) K, (b) Rb, and (c) Cs compounds. The view of the
V2O3 SO4
4−
4
(
)
ion along the intersection line of the V(1)–O(16)–V(2) plane with the plane perpendicular to the V(1)–V(2) line
V2O3 SO4
for (d) K, (e) Rb, and (f) Cs compounds.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 4 2011

494
KRASIL’NIKOV et al.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 4 2011

SYNTHESIS, CRYSTAL STRUCTURE, AND VIBRATIONAL SPECTRA
Table 3. Shortest interatomic distances (Å) in M4V2O3(SO4)4 (M = K, Rb, Cs)
Rb Cs
1.56(1) 1.64(2)
495
K
K
Rb
Cs
V(1)–O(19)
V(1)–O(16)
V(1)–O(2)
V(1)–O(3)
V(1)–O(8)
V(1)–O(6)
Average
1.56(2)
V(2)–O(10)
V(2)–O(16)
V(2)–O(11)
V(2)–O(9)
V(2)–O(1)
V(2)–O(5)
Average
1.56(2)
1.77(2)
2.03(2)
1.95(2)
2.44(2)
2.00(2)
1.96
1.54(1)
1.79(1)
1.98(1)
1.88(1)
2.38(1)
2.05(1)
1.95
1.60(2)
1.78(2)
1.85(2)
1.97(2)
2.05(2)
2.39(2)
1.94
1.81(2)
1.88(2)
1.94(2)
2.01(2)
2.46(2)
1.94
1.76(1)
1.90(1)
1.97(1)
2.05(1)
2.48(1)
1.95
1.76(2)
1.86(2)
1.96(2)
2.06(2)
2.41(2)
1.95
Expected
*
1.92
1.92
1.92
Expected
1.92
1.92
1.92
S(1)–O(5)
S(1)–O(11)
S(1)–O(12)
S(1)–O(17)
Average
1.54(2)
1.60(2)
1.50(2)
1.45(2)
1.52
1.53(1)
1.51(1)
1.45(1)
1.46(1)
1.49
1.48(2)
1.53(2)
1.46(2)
1.43(2)
1.48
S(2)–O(2)
S(2)–O(6)
S(2)–O(7)
S(2)–O(13)
Average
1.54(2)
1.50(2)
1.44(2)
1.49(2)
1.49
1.61(1)
1.45(1)
1.47(1)
1.50(1)
1.51
1.53(2)
1.50(2)
1.45(2)
1.39(2)
1.47
Expected
*
1.50
1.50
1.50
Expected
1.50
1.50
1.50
S(3)–O(3)
S(3)–O(8)
S(3)–O(14)
S(3)–O(18)
Average
1.56(2)
1.42(2)
1.52(2)
1.42(2)
1.48
1.52(1)
1.57(1)
1.47(1)
1.44(1)
1.50
1.52(2)
1.49(2)
1.38(2)
1.46(2)
1.46
S(4)–O(1)
S(4)–O(4)
S(4)–O(9)
S(4)–O(15)
Average
1.48(2)
1.48(2)
1.56(2)
1.46(2)
1.50
1.47(1)
1.42(1)
1.55(1)
1.44(1)
1.47
1.53(2)
1.43(2)
1.61(2)
1.43(2)
1.50
Expected
*
1.50
1.50
1.50
Expected
1.50
1.50
1.50
*The expected distances were calculated as the sum of crystal radii according to [21].
The unit cell of M4V2O3(SO4)4 (M = K, Rb, Cs) way that the O(19)=V(1)–V(2)=O(10) torsion angles
compounds contains two discrete complex ions
are 165.7
°
(K), 164.8
°
(Rb), and 127.7° (Cs), respecꢀ
4−
the M+ cations being arranged in the
tively. It can be clearly seen in Figs. 1d–1f that the
V O SO
4
,
(
)
2
3
free space b4etween the complex ions. A specific feature
4−
complex anions
in the potassium and
V O SO
4
4
(
)
2
3
4−
of
(Fig. 1) is that it contains two vanaꢀ
V O SO
4
4
(
)
rubidium compounds are symmetrical with respect to
a twofold axis passing through the O(16) atom. The
direction of the axis is specified by intersection of the
V(1)–O(16)–V(2) plane with the plane perpendicular
to the V(1)–V(2) direction, that is, upon the rotation
2
3
dium atoms, each in a distorted octahedral oxygen
environment, linked to form a pair by cisꢀarranged
O(16) oxygen bridging atom with a VOV bond angle of
160.0
°
, 162.7
°
, and 166.6 and a V–V distance of 3.52,
°
3.51, and 3.52 Å for potassium, rubidium, and cesium
compounds, respectively. The vanadium–oxygen
interatomic distances in the VO6 octahedra are nonꢀ
equivalent (Table 3), each octahedron having a short
V=O terminal bond with lengths of 1.56 Å (K), 1.56
and 1.54 Å (Rb), and 1.64 and 1.60 Å (Cs). The V–O
of the complex anion around this axis by 180 , the
atom positions coincide. However, in the cesium comꢀ
°
4−
pound, the
is less symmetric. Both its
V O SO
4
4
(
)
2
3
halves nearly coincide upon the translation of V(2) to
the position of V(1) with simultaneous inversion of the
close environment of V(2) and rotation around it until
bond lengths in the V–O–V bridge are 1.81 and 1.77
(K), 1.79 and 1.76 Å (Rb), 1.78 and 1.76 Å (Cs). The
Å
octahedra are rotated relative to each other in such a coincidence with the atoms that surround V(1).
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 4 2011

496
Table 4. Bond angles OVO (ω) in M4V2O3(SO4)4 (M = K, Rb, Cs)
, deg
KRASIL’NIKOV et al.
ω
ω
, deg
Angle
K
Rb
Cs
Angle
K
Rb
Cs
O(2)V(1)O(3)
O(2)V(1)O(6)
O(2)V(1)O(8)
O(2)V(1)O(16)
O(2)V(1)O(19)
O(3)V(1)O(6)
O(3)V(1)O(8)
O(3)V(1)O(16)
O(3)V(1)O(19)
O(6)V(1)O(8)
O(6)V(1)O(16)
O(6)V(1)O(19)
O(8)V(1)O(16)
O(8)V(1)O(19)
O(16)V(1)O(19)
148.7(8)
64.5(7)
89.8(7)
103.4(7)
100.1(8)
89.3(7)
67.8(6)
88.2(7)
104.8(8)
79.3(7)
81.7(7)
164.5(7)
149.3(8)
99.8(9)
104.9(9)
149.6(6)
65.0(6)
87.7(5)
104.6(6)
98.1(6)
89.6(6)
70.0(5)
88.1(5)
106.3(7)
77.9(6)
84.0(6)
163.1(6)
151.3(6)
101.9(7)
101.8(7)
147.0(7)
64.4(7)
92.3(7)
102.0(8)
99.8(9)
87.3(8)
65.9(7)
89.7(8)
107.4(8)
82.2(8)
81.9(8)
164.3(8)
151.4(8)
98.6(8)
103.2(9)
O(11)V(2)O(9)
O(11)V(2)O(5)
O(11)V(2)O(1)
O(11)V(2)O(16)
O(11)V(2)O(10)
O(9)V(2)O(5)
O(9)V(2)O(1)
O(9)V(2)O(16)
O(9)V(2)O(10)
O(5)V(2)O(1)
O(5)V(2)O(16)
O(5)V(2)O(10)
O(1)V(2)O(16)
O(1)V(2)O(10)
O(16)V(2)O(10)
147.3(8)
71.4(7)
85.7(7)
87.2(7)
109.5(9)
88.4(7)
65.1(7)
102.2(8)
100.0(9)
79.3(7)
152.6(8)
104.2(9)
82.4(7)
164.8(7)
98.8(9)
147.3(6)
70.1(5)
87.0(6)
88.6(6)
109.7(7)
88.3(5)
65.2(6)
103.2(6)
97.4(7)
81.7(6)
153.6(6)
98.8(6)
81.9(6)
162.5(6)
103.0(7)
147.7(9)
63.5(8)
91.7(7)
101.2(8)
101.2(9)
87.6(8)
69.4(7)
88.7(8)
106.5(9)
82.5(8)
83.7(8)
164.4(8)
154.5(8)
96.0(9)
103.0(9)
Table 5. Bond angles OSO (ω) in M4V2O3(SO4)4 (M = K, Rb, Cs)
, deg
ω
ω
, deg
Angle
K
Rb
Cs
Angle
K
Rb
Cs
O(5)S(1)O(11)
O(5)S(1)O(12)
O(5)S(1)O(17)
O(11)S(1)O(12)
O(11)S(1)O(17)
O(12)S(1)O(17)
O(3)S(3)O(8)
97.0(9)
106.5(9)
108.6(9)
108.1(9)
112.8(9)
120.9(9)
95.7(9)
98.9(8)
112.6(9)
110.4(8)
109.9(8)
110.7(8)
113.5(8)
96.4(7)
98.4(9)
114.2(9)
113.9(9)
107.5(9)
110.1(9)
111.6(9)
93.5(9)
O(2)S(2)O(6)
O(2)S(2)O(7)
O(2)S(2)O(13)
O(6)S(2)O(7)
O(6)S(2)O(13)
O(7)S(2)O(13)
O(1)S(4)O(4)
O(1)S(4)O(9)
O(1)S(4)O(15)
O(4)S(4)O(9)
O(4)S(4)O(15)
O(9)S(4)O(15)
102.2(9)
109.4(9)
108.5(9)
113.7(9)
112.3(9)
110.3(9)
110.0(9)
104.0(9)
113.6(9)
105.2(9)
116.3(9)
106.4(9)
103.1(8)
106.2(8)
106.8(8)
113.1(9)
115.6(8)
111.1(9)
111.4(9)
100.7(9)
114.8(9)
107.2(9)
114.9(9)
106.3(9)
100.2(9)
103.8(9)
105.3(9)
112.6(9)
116.4(9)
116.0(9)
112.5(9)
93.5(9)
O(3)S(3)O(14)
O(3)S(3)O(18)
O(8)S(3)O(14)
O(8)S(3)O(18)
O(14)S(3)O(18)
110.8(9)
111.9(9)
111.1(9)
116.0(9)
110.5(9)
116.0(9)
109.1(8)
106.9(8)
109.2(9)
117.0(9)
114.7(9)
111.3(9)
107.4(9)
109.5(9)
117.6(9)
107.9(9)
107.1(9)
122.3(9)
109.7(9)
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 4 2011

SYNTHESIS, CRYSTAL STRUCTURE, AND VIBRATIONAL SPECTRA
(а) (b)
497
116.9
°
3.25
Å
b
136.4
°
6.40
Å
136.4
°
116.9
°
136.4
°
4.83
Å
а
4.97
Å
6.56
Å
3.52
Å
b
а
6.52
Å
c
6.73
Å
c
4–
Fig. 2. Schematic view of the mutual orientation of the V O (SO ) complex ions for (a) K, (b) Cs compounds. The V(1) atoms
2
3
4
4
are colored gray, V(2) are colored black, the thick black line shows the V(1)–V(2) distance within the complex ion, the thin conꢀ
tinuous line is the distance to the nearest vanadium atom of the other ion, and the dashed line shows the next shortest distances.
4−
All of the four sulfate groups in the
(K) and 4.94 Å (Cs)), the VVV angles being 136.4
136.1 , respectively. The neighboring chains are
°
and
V O SO
4
4
(
)
2
3
°
complex anion are coordinated by vanadium in the
chelating mode and have large scatter of the S–O
interatomic distances and OSO bond angles (Tables 3,
5). On going from the potassium and rubidium comꢀ
pounds to the cesium compound, the symmetry of the
complex anion changes in such a way that O(1) from
the environment of S(4) rather than O(5) from the
environment of S(1) (as in the cesium compound)
occurs in the transꢀposition to the V(2)=O(10) group.
The atom symmetry around V(1) remains almost
invariable, and for all compounds, the transꢀposition
to the V(1)=O(19) group is occupied by O(6) from the
environment of S(2). The S–O bond length (to the
transꢀposition) is the largest in the oxygen tetrahedron
(Table 3). All tetrahedra are highly distorted, and one
arranged at distances of 6.52 and 6.73 Å (K), 6.79 and
6.99 Å (Rb). The large radius of cesium results in
cleavage of the chains and is accompanied by formaꢀ
tion of pairs of complex anions, in each of them the
V(1) atom of one anion being located most closely to
the V(1) atom of the other anion (4.97 Å). As a conseꢀ
quence, the VVV angle in this pair is 116.9 , which is
°
much smaller than that in the potassium and rubidium
compounds. The neighboring pairs are located at disꢀ
tances of 6.40 and 6.56 Å. This change in the mutual
orientation of complex anions makes it possible to
avoid the formation of large voids in the environment
of alkali metal atoms on going from K and Rb to Cs.
A comparison of the parameters of the chemical
shift tensor for M4V2O3(SO4)4 [3] presented in Table 6
provides grounds for the conclusion that the potasꢀ
of the OSO angles is about ~95
°
, which is much
smaller than the ideal tetrahedral angle (109.5
°
). The
tetrahedra comprising the oxygen atoms located in the
transꢀposition to the terminal V=O group are less disꢀ
torted.
Table 6. Chemical shift tensor (ppm) for M4V2O3(SO4)4 [3]
Apart from the symmetry difference of the proper
4−
Compound
–σ1
–σ2
–σ3
–
σ
–σiso Δσ
⊥
complex anions, the mutual orientation
V O SO
4
4
(
)
2
3
of the anions also changes on going from the potasꢀ
sium and rubidium compounds to the cesium comꢀ
pound. For clarity, Fig. 2 shows only vanadium atoms
for the potassium and cesium compounds (for rubidꢀ
ium, the picture is nearly the same as for potassium).
This construction shows that the complex anions in
the potassium and rubidium compounds form a zigꢀ
K4V2O3(SO4)4
325 365 1400 345 696 1075
Rb4V2O3(SO4)4 315 371 1425 343 703 1082
Cs4V2O3(SO4)4 365 365 1340 365 690 975
zagꢀlike chain along the
a axis; the nearest neighbor of
V(1) of one ion is the V(2) atom of the other ion (4.83
Å
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 4 2011

498
KRASIL’NIKOV et al.
Table 7. Wave numbers (cm–1) of the absorption maxima in
sium and rubidium compounds have the same type of
local environment of vanadium, which differs someꢀ
what from that in the cesium compound. Some differꢀ
ences are observed also in the vibrational spectra of
M4V2O3(SO4)4, the high similarity of the spectra of
potassium and rubidium compounds being indicative
of the full identity of shortꢀrange order elements in
their crystal structure. The presence of highly distorted
VO6 octahedra and SO4 groups with no equivalent V–O
and S–O bonds in M4V2O3(SO4)4 accounts for comꢀ
plexity of their vibrational spectra (Figs 3, 4, Table 7).
The character of vibration frequencies of the sulfate
ligands manifested in the IR and Raman spectra fully
corresponds to the bidentate chelating mode [19] of
their coordination by vanadium and to the nonequivꢀ
alence of the S–O bonds in these complexes. The antiꢀ
the vibrational spectra M4V2O3(SO4)4
K4V2O3(SO4)4 Rb4V2O3(SO4)4 Cs4V2O3(SO4)4
Assignment
IR Raman IR Raman IR Raman
1285 1215 1282 1210 1297 1207
1282
ν
3(SO4)
1257
1224
1254
1223
1252
1202 1180
1183 1169 1180 1173 1167 1167
1034 1034 1032 1034 1022 1022
ν
1(SO4),
(V=O)
1004 1004 1002 1004
999
983
949
933
905
858
817
767
705
663
644
615
996
988
951
ν
symmetric stretching mode (ν3) of the 2− ion in the
SO4
966
948
963
945
IR spectra of these compounds is split into four comꢀ
ponent or into five components in the case of cesium,
which are manifested as strong bands (Fig. 3). The
ν1(SO4) symmetrical stretching vibrations are responꢀ
sible for the strong band at 1034 cm–1 (K), 1032 cm–1
(Rb), and 1022 cm–1 (Cs). In the region of ν4(SO4)
asymmetric bending mode, rather strong bands occur
at 616–669 cm–1 (K), 616–666 cm–1 (Rb), and 615–
663 cm–1 (Cs). The symmetric bending mode ν2(SO4)
in the IR spectra of potassium and rubidium compounds
is split into two components, while in the IR spectrum of
Cs4V2O3(SO4)4, this is a weak band at 427 cm–1. The
short V–O bands in M4V2O3(SO4)4 account for a numꢀ
ber of strong IR bands at 948–1004 cm–1 (K), 945–
1002 cm–1 (Rb), and 933–999 cm–1 (Cs). The antiꢀ
symmetric and symmetric vibrations of the V–O–V
bridges are probably responsible for the strong bands at
712–914 and 516–587 cm–1 (K), 708–916, and 515–
580 cm–1 (Rb), 515–905 and 516–583 cm–1 (Cs),
respectively. In the Raman spectra of M4V2O3(SO4)4
(M = K and Rb), the vibrations of short terminal V–O
bonds are manifested as a very strong line at 1004 cm–1,
and the Raman spectrum of the cesium compound
shows two mediumꢀintensity lines in this region, at
996 and 988 cm–1. The spectra of all compounds have
a very strong band at 705 cm–1. The lines correspondꢀ
ing to SO4 groups are weak, except for ν2(SO4), which
914 920
862 852
818 817
761 758
712 705
669
916
859
819
757
708
666
652
616
920
853
816
760
705
ν
(V–O–V)
868
818
766
705
ν
4(SO4)
655
648
622
646
622
616 616
587
δ
(V–O–V),
580 580
540 538
516
580
532
515
465
424
386
371
327
302
289
278
242
226
210
580
538
583
535
516
583
533
ν
(V–O–S)
460 464
427
462
387
457
427
393
379
327
302
290
ν
2(SO4)
386 390
374
390 External opꢀ
tical modes
is a rather strong line at 464 cm–1 (K), 462 cm–1 (Rb),
and 457 cm–1 (Cs). Thus, the data of vibrational specꢀ
troscopy are in good agreement with the crystal strucꢀ
379
323
324
307
327
288
249
210
ture of M4V2O3(SO4)4. In the oxosulfate V2O3(SO4)2
the lengths of the short terminal V–O bonds are equal
1.565 Å), the vanadium–oxygen bond lengths in the
,
302 312
290
(
V–O–V bridges almost coincide, V(1)–O = 1.781 Å,
V(2)–O = 1.780 Å. Therefore, the vibrational spectra
of this compound show only two bands, 1010 (IR),
1011 cm–1 (Raman) and 790 (IR), 750 cm–1 (Raman),
for the vibrations of short terminal V–O bonds and
279 280
245
277
249
226
249
227
208
227 224
208
V⎯O–V bridges [20]. The observed differences
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 4 2011

SYNTHESIS, CRYSTAL STRUCTURE, AND VIBRATIONAL SPECTRA
499
3
2
1
3
2
1400 1200 1000 800
, cm–1
600
400
200
ν
Fig. 3. IR spectra of M V O (SO ) , where M = (1) K, (2)
4
2
3
4 4
1
Rb (2), and (3) Cs.
between the parameters of the chemical shift tensor in
the 51V NMR spectra [3] and the vibrational spectra of
M4V2O3(SO4)4 (M = K, Rb) and Cs4V2O3(SO4)4 are in
1200 1000 800
600
Δν, cm–1
400
200
good agreement with the established different type of
Fig. 4. Raman spectra of M V O (SO ) , where M = (1)
4
2
3
4 4
4−
symmetry of the
complex anions and
V O SO
4
4
(
)
K, (2) Rb (2), and (3) Cs.
2
3
their mutual orientation in the structures of these
compounds.
However, in the M4V2O3(SO4)4 series, the potassium
and rubidium compounds form a separate group of
structural analogs characterized by higher symmetry
Our structural study demonstrated that the comꢀ
plexes M4V2O3(SO4)4 crystallize with the triclinic sysꢀ
tem with the same space group
and the number of
P1
of the
4− complex anions and the same type
V O SO
4
(
)
formula units
Z = 2. The crystal structure of
2
3
4
4−
of their mutual spatial orientation (Figs. 1, 2). These
structural features are reflected in some properties of
compounds, for example, the patterns of 51V NMR
and vibrational spectra and the colors of the powders,
which are orange for M4V2O3(SO4)4 (M = K, Rb) and
M4V2O3(SO4)4 is formed by discrete
V O SO
4
4
,
(
)
2
3
complex anions in which the vanadium atoms have a
distorted octahedral environment and are connected
to each other by the bridging oxygen. Each vanadium
atom is chelated by two SO4 groups and coordinates one
oxygen atom with a V–O bond length of about 1.6 Å.
yellow for Cs4V2O3(SO4)4
.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 4 2011

500
KRASIL’NIKOV et al.
11. F. Abdoun, G. Hatem, M. GauneꢀEscard, et al.,
REFERENCES
J. Phys. Chem. B 103, 3559 (1999).
12. G. E. Folkmann, G. Hatem, R. Fehrmann, et al.,
Inorg. Chem. 30, 4057 (1991).
13. K. Nielsen, R. Fehrmann, and K. M. Eriksen, Inorg.
1. A. Kato, K. Tomoda, I. Mochida, and T. Seiyama, Bull.
Chem. Soc. Jpn. 45, 690 (1972).
2. V. M. Mastikhin, O. B. Lapina, B. S. Balzhinimaev,
et al., J. Catal. 103, 160 (1987).
Chem. 32, 4825 (1993).
3. O. B. Lapina, V. M. Mastikhin, A. A. Shubin, et al.,
14. E. Thilo and F. Lampe, Z. Anorg. Allg. Chem. 319, 387
Progr. NMR Spectrosc. 24, 457 (1992).
(1963).
4. G. Hatem, K. M. Eriksen, M. GauneꢀEscard, et al.,
15. A. Altomare, M. C. Burla, B. Carrozzini, et al., J. Appl.
Topics in Catalysis 19, 323, (2002).
Crystallogr. 32, 339 (1999).
16. A. C. Larson and R. B. Von Dreele, GSAS LANSSCE,
Los Alamos Natl. Lab., MSꢀH805.
5. O. B. Lapina, A. A. Shubin, D. F. Khabibulin, et al.,
Catal. Today 78, 91 (2003).
17. V. N. Krasil’nikov, Zh. Neorg. Khim. 29, 1183 (1984).
18. V. N. Krasil’nikov and A. D. Galaktionov, Zh. Neorg.
6. A. Christodoulakis and S. Boghosian, J. Catal. 215, 139
(2003).
Khim. 42, 915 (1997).
7. V. N. Krasil’nikov and M. P. Glazyrin, Zh. Neorg.
19. K. Nakamoto, Infrared and Raman Spectra of Inorganic
and Coordination Compounds (Wiley, New York, 1986;
Mir, Moscow, 1991).
Khim. 27, 2659 (1982).
8. V. N. Krasil’nikov, M. P. Glazyrin, A. P. Palkin, et al.,
Zh. Neorg. Khim. 32, 760 (1987).
20. K.ꢀL. Richter and R. Mattes, Z. Anorg. Allg. Chem.
9. V. N. Krasil’nikov, Zh. Neorg. Khim. 52, 471 (2007).
611, 158 (1992).
10. G. E. Folkmann, G. Hatem, R. Fehrmann, et al., 21. R. D. Shannon, Acta Crystallogr., Sect. A 32, 751
J. Phys. Chem. B 102, 24 (1998).
(1976).
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 4 2011