K3VO2(SO4)2: Formation conditions, crystal structure, and physicochemical properties

Article abstract of DOI:10.1134/S0036023610081029

Potassium oxosulfatovanadate(V) K₃VO₂(SO ₄)₂ has been obtained by solid-phase synthesis from K ₂SO₄, K₂S₂O₇, and V ₂O₅ (2: 1: 1), and

Full text of DOI:10.1134/S0036023610081029

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2011, Vol. 56, No. 1, pp. 18–25. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © V.N. Krasil’nikov, A.P. Tyutyunnik, V.G. Zubkov, I.F. Berger, L.A. Perelyaeva, I.V. Baklanova, 2011, published in Zhurnal Neorganicheskoi Khimii, 2011,
Vol. 56, No. 1, pp. 20–28.
SYNTHESIS AND PROPERTIES
OF INORGANIC COMPOUNDS
K3VO2(SO4)2: Formation Conditions, Crystal Structure,
and Physicochemical Properties
V. N. Krasil’nikov, A. P. Tyutyunnik, V. G. Zubkov, I. F. Berger,
L. A. Perelyaeva, and I. V. Baklanova
Institute of Solid State Chemistry, Ural Branch, Russian Academy of Sciences,
Pervomaiskaya ul. 91, Yekaterinburg, 620219 Russia
Received February 27, 2009
Abstract—Potassium oxosulfatovanadate(V) K3VO2(SO4)2 has been obtained by solidꢀphase synthesis from
K2SO4, K2S2O7, and V2O5 (2 : 1 : 1), and its formation conditions, crystal structure, and physiochemical
properties have been studied. The conversions of K3VO2(SO4)2 in contact with potassium vanadates and other
potassium oxosulfatovanadates(V) are considered in terms of phase relations in the K2O–V2O5–SO3 system,
which models the active component of vanadium catalysts for sulfur dioxide oxidation into sulfur trioxide.
The Xꢀray diffraction pattern of K3VO2(SO4)2 is indexed in the monoclinic system (space group
P
21) with
unit cell parameters of
a
= 10.0408(1)
Å,
b
= 7.2312(1)
Å,
c
= 7.3821(1)
Å,
β
= 104.457(1) , Z = 2, and V =
°
519.02 Å3. The crystal structure of K3VO2(SO4)2 is built from [VO2(SO4)2]3– complex anions, in which the
vanadium atom is in an octahedral oxygen environment formed by two terminal oxygen atoms (V–O(6) =
1.605(7) Å, V–O(10) = 1.619(7) Å) and four oxygen atoms of the two chelating sulfate anions. The vibrational
spectra of K3VO2(SO4)2 are analyzed using these structural data.
DOI: 10.1134/S0036023610081029
The K2O–V2O5–SO3–H2O system has drawn cochemical properties of the potassium oxosulfatoꢀ
researchers’ attention because of its relevance to the vanadate(V) K3VO2(SO4)2
.
active component of industrial vanadium catalysts for
sulfur dioxide conversion into sulfur trioxide [1–3].
Five vanadium(V) complexes were synthesized and
identified through analysis of phase relations in the
K2O–V2O5–SO3 ternary system [1, 4, 5], and they
were interpreted as the potassium oxosulfatovanaꢀ
dates(V) K3VO2(SO4)2, KVO2SO4, K4V2O3(SO4)4,
K3VO(SO4)3, and KVO(SO4)2. A single crystal of
K8V2O3(SO4)6, another oxosulfatovanadate, was grown
from the K2SO4–K2S2O7–V2O5 melt [6]. However, the
solidꢀphase synthesis of this compound failed. Studies
of the interaction of potassium oxosulfatovanaꢀ
dates(V) with water vapor [1, 7–11] and solubility
measurements in the KVO2SO4–K2SO4–H2SO4–H2O
system [1, 12] led to the synthesis of the hydrates
EXPERIMENTAL
The following solidꢀphase reactions were carried
out for K3VO2(SO4)2 synthesis:
2K2SO4 + K2S2O7 + V2O5 = 2K3VO2(SO4)2, (1)
K2SO4 + KVO2SO4 = K3VO2(SO4)2,
K2S2O7 + KVO3 = K3VO2(SO4)2,
(2)
(3)
2K3H(SO4)2 + V2O5 = 2K3VO2(SO4)2 + H2O
↑
, (4)
. (5)
KVO(SO4)2 + K2CO3 = K3VO2(SO4)2 + CO2
↑
Mixtures of the reactants involved in reactions (1)–
(5) were thoroughly ground in an agate mortar and
were annealed in platinum crucibles at 200–330 С. To
avoid the effect of atmospheric moisture, intermediate
grindings were performed in mortars heated to 40–
K[VO2(SO4)(H2O)2]
⋅
H2O and K[VO2(SO4)(H2O)].
°
51V NMR characterization of anhydrous and hydrated
potassium oxosulfatovanadates(V) suggested that the
vanadium atoms in their crystal structures are in a disꢀ
torted octahedral environment similar to the environꢀ
ment of vanadium in vanadium(V) oxide and that the
degree of distortion of the VO6 octahedra is composiꢀ
tionꢀdependent [13]. According to Xꢀray crystallograꢀ
phy data, the crystal structures of K8V2O3(SO4)6 [6],
50 С and the synthesized compounds were stored in
°
hermetically sealed vessels. The main starting chemiꢀ
cals were K2CO3, K2SO4, V2O5 (highꢀpurity grade),
and K2S2O8 (analytical grade). K2S2O7 was synthesized
by K2S2O8 thermolysis at 300 С [17]. Potassium metaꢀ
vanadate (KVO3) was obtained by the solidꢀphase
reaction between stoichiometric amounts of K2CO3
°
KVO2SO4 [14], KVO(SO4)2 [15], K[VO2(SO4)(H2O)2]
H2O [11, 16], and K[VO2(SO4)(H2O)] [11] are indeed
built of VO6 octahedra, whose distortion is governed by K[VO2(SO4)(H2O)2]
⋅
and V2O5 [1]
;
KVO2SO4, by heat treatment of
H2O [1, 14], K3H(SO4)2, by crysꢀ
⋅
the presence of short terminal V–O bonds. Here, we tallization from a cooled solution of K2SO4 in dilute
report the formation conditions, structure, and physiꢀ sulfuric acid [1]. The completeness of the reaction and
18

K3VO2(SO4)2: FORMATION CONDITIONS
19
Table 1. Refractive indexes of the potassium, rubidium, and cesium compounds used in phase analysis
Compound
Ng
Nm
Np
Color of the powder
K2CO3
K2SO4
KHSO4
1.541
1.497
1.491
1.526
1.482
1.908
2.47
1.532
1.494
1.460
1.490
1.466
1.800
–
1.426
1.493
1.445
1.479
1.458
1.750
1.745
1.770
Colorless
The same
''
K3H(SO4)2
K2S2O7
''
''
KVO3
''
K3V5O14
Orangeꢀred
Yellow
K2V6O16
2.34
2.27
–
K2V8O21
2.50>
2.57
>2.0
Dark brown
Green
K2V8O20.8
–
1.838
1.750
1.509
1.510
1.588
1.555
KVO2SO4
2.030
1.553
1.690
–
–
Orangeꢀbrown
Yellowish
Dark yellow
Orangeꢀyellow
Yellow
K3VO2(SO4)2
K3VO(SO4)3
KVO(SO4)2
K[VO2(SO4)(H2O)2] · H2O
–
–
1.703
1.592
1.610
product purity were checked by transmission light and neutron diffraction data. Peak profiles were
approximated by the pseudoꢀVoigt function:
(2 (1 – )* (2 ) ( and are Lorentzian and
Gaussian functions). The angular dependence of line
I
(2
θ
) =
microscopy (POLAM Sꢀ112 polarized light microꢀ
scope) using the optical immersion technique and by
Xꢀray powder diffraction. The refractive indexes of the
compounds used in the microscopic phase analysis are
listed in Table 1. IR absorption spectra were recorded
as mineralꢀoil mulls in the 400–1200 cm–1 range on a
Spectrum One spectrometer (PerkinꢀElmer). Raman
spectra were recorded on a Renishaw 1000 spectromꢀ
η*L
θ)
+
η
G
θ
L
G
width was approximated as (FWHM)2 =
U
tan2
θ
+
V
tanθ + W, where FWHM is the full width at half
maximum. The background level was expressed as a
combination of 15 Chebyshev polynomials. The results
of structure refinement are presented in Table 2. The
bond lengths and bond angles are listed in Table 3.
eter (Ar+ laser,
λ
= 514.5 nm). Thermal properties
were studied using a Qꢀ1500D thermal analyzer and
an MINꢀ8 polarizedꢀlight microscope fitted with a hot
stage attachment [1, 18].
RESULTS AND DISCUSSION
The Xꢀray diffraction patterns of K3VO2(SO4)2
Our experiments demonstrated that K3VO2(SO4)2
can be obtained by solidꢀphase synthesis via reactions
(1)–(5). The synthesis via reaction (2) is the least
laborious and the simplest. Reaction (5) is compliꢀ
cated by the high hygroscopicity of KVO(SO4)2. The
reaction between K2S2O7 and KVO3 takes place in
accordance with the K2O–V2O5–SO3 phase diagram
(Fig. 1) via the successive formation of potassiumꢀ
powder were obtained on an STADIꢀP automated difꢀ
fractometer (CuK 1 radiation) with a miniꢀPSD in the
α
transmission mode in the
= 0.02 increments. The external standard was
polycrystalline silicon ( = 5.43075(5) Å). Impurity
2θ = 2°–120° range with
Δ2θ
°
a
phases were identified using the ICDD PDFꢀ2 dataꢀ
base (Release 2007). Neutron diffraction patterns
were obtained at room temperature on a D7A diffracꢀ
tometer at an IVV 2M reactor (Zarechnyi, Sverdlovsk
poorer vanadates (KVO3
K3V5O14
K2V6O16
K2V8O21) accompanied by K2SO4 buildup. The main
intermediate products of reaction (3) are KVO2SO4
oblast) in the
ments at a neutron wavelength of
2
θ
= 10
°
–120
°
range with 0.05
°
increꢀ
λ
= 1.5334 Å. The
and K2SO4, whose interaction yields K3VO2(SO4)2
.
crystal structure of K3VO2(SO4)2 was reconstructed by
direct methods using the EXPO program [19] and
Xꢀray diffraction data. The structure was finally
Heat treatment of a 2K2SO4 + K2S2O7 + V2O5 mixture
initially yields KVO2SO4 due to the reaction between
refined with the GSAS program [20] using both Xꢀray vanadium(V) oxide and potassium sulfate, an this is
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 1 2011

20
KRASIL’NIKOV et al.
Table 2. Atomic coordinates and thermal parameters (×102, Å2) in K3VO2(SO4)2
Atom
Position
x
/a
y
/b
z/
c
Uiso/Ueq
K(1)
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
0.4138(4)
0.2705(4)
0.0485(4)
0.8546(3)
0.6553(4)
0.7478(5)
0.8836(7)
0.6593(8)
0.7438(7)
0.7052(7)
0.5097(8)
0.0085(7)
0.6908(7)
0.7812(8)
0.6906(7)
0.8713(7)
2) = 3.50%.
0.1115(6)
0.8416(5)
0.4158(6)
0.8415(6)
0.8146(8)
0.1525(7)
0.095(1)
0.990(1)
0.982(1)
0.6850(9)
0.853(1)
0.310(1)
0.303(1)
0.206(1)
0.7268(9)
0.7102(9)
0.5835(5)
0.9887(4)
0.7095(5)
0.7531(4)
0.9521(6)
0.5392(6)
0.6709(9)
0.519(1)
0.9517(9)
0.813(1)
0.880(1)
0.0832(9)
0.6232(9)
0.360(1)
0.132(1)
0.583(1)
2.9(1)
2.4(1)
3.1(2)
2.6(1)
1.9(1)
3.2(2)
1.7(2)
2.2(2)
2.1(2)
1.9(2)
3.4(2)
2.9(2)
2.8(3)
2.9(2)
2.2(2)
2.6(2)
K(2)
K(3)
V
S(1)
S(2)
O(1)
O(2)
O(3)
O(4)
O(5)
O(6)
O(7)
O(8)
O(9)
O(10)
Xꢀray diffraction: wRp = 2.31%,
Rp = 1.77%,
R(F
Neutron diffraction: wRp = 2.28%,
Rp = 1.78%, R(F2) = 3.61%.
followed by reaction (2). These facts were the main 1100
reason for selecting reaction (2) as the way to syntheꢀ KV6O15 was considered to be the initial interaction
size singleꢀphase K3VO2(SO4)2 product in the K2SO4–V2O5 system above 450 [29]:
°С for many hours. The vanadium oxide bronze
.
°С
The absence of the K2SO4–V2O5 pseudobinary join
in the K2O–V2O5–SO3 diagram (Fig. 1) disproves the
information concerning the existence of soꢀcalled sulꢀ
K2SO4 + 6V2O5 = 2KV6O15 + 1/2O2 + SO3. (7)
However, we did not identify the KV6O15 bronze
among the products of interaction between K2SO4 and
V2O5. The authors who studied the interaction
between potassium sulfate and vanadium(V) oxide
under nonequilibrium conditions [30–33] did not
detect this compound either. Vibrational spectroscopy
data [33–35] suggest that the following reaction takes
place in the molten K2SO4 + V2O5 mixture:
fovanadates with the general formula
mK2SO4 nV2O5
⋅
[21–24], even though they are still considered to be
the active component of vanadium catalysts for sulfur
dioxide conversion [25–27]. The interaction between
K2SO4 and V2O5 below 400 С proceeds very slowly,
°
yielding solid phases belonging to the K2SO4–
K2V8O21–K3VO2(SO4)2 and K2V8O21–K3VO2(SO4)2–
V2O5 ternary systems, and this is not accompanied by
any changes in the sample weight. An example of this
interaction is
2K2SO4 + V2O5 = K3VO2(SO4)2 + KVO3.
(8)
As is clear from the K2O–V2O5–SO3 diagram (Fig. 1),
this process is impossible in the subsolidus region
because the K3VO2(SO4)2–KVO3 system is nonequilibꢀ
rium. The following reactions occur as a mixture of
K3VO2(SO4)2 and a potassium vanadate is heated:
4K2SO4 + 5V2O5
(6)
=
2K3VO2(SO4)2 + K2V8O21 (330°C).
2K3VO2(SO4)2 + 4KVO3 = 4K2SO4 + K2V6O16, (9)
K3VO2(SO4)2 + K3VO4 = 2K2SO4 + KVO3. (10)
Heating of K3VO2(SO4)2 with KVO(SO4)2 results in
Potassium octavanadate, K2V8O21, is stable in air at
450 . At higher temperatures, it turns into the
vanadium oxide bronze K2V8O20.8 [28]. Above 500
the reaction mixture releases gaseous SO3, yielding
T
≤
°С
°С,
other potassium vanadates (Fig. 1) up to KVO3. Vanaꢀ the formation of potassium oxosulfatovanadate
dates richer in potassium than KVO3 do not form from K4V2O3(SO4)4, which belongs to the K2S2O7–V2O5
K2SO4 mixtures even as the molten stock is held at pseudobinary system (Fig. 1).
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 1 2011

K3VO2(SO4)2: FORMATION CONDITIONS
21
Table 3. Interatomic distances (d, Å) and bond angles (ω, deg) in the K3VO2(SO4)2 structure
Bond
d
Bond
d
Bond
d
K(1)–O(2)
K(1)–O(2)
K(1)–O(4)
K(1)–O(5)
K(1)–O(7)
K(1)–O(7)
K(1)–O(9)
K(1)–O(10)
Average
2.769(8)
2.883(8)
2.921(8)
2.857(8)
3.056(7)
2.756(8)
2.704(8)
2.908(7)
2.857
K(2)–O(3)
K(2)–O(4)
K(2)–O(5)
K(2)–O(6)
K(2)–O(7)
K(2)–O(8)
K(2)–O(9)
Average
2.646(8)
2.862(7)
2.717(8)
2.727(8)
2.807(7)
2.684(8)
2.979(8)
2.775
K(3)–O(1)
K(3)–O(3)
K(3)–O(6)
K(3)–O(8)
K(3)–O(9)
K(3)–O(10)
K(3)–O(10)
Average
2.825(8)
2.869(7)
2.986(8)
2.831(8)
2.927(8)
2.783(8)
2.894(8)
2.874
K+ VII
2.84
K+ VII
2.84
K+ VIII
2.89
V–O(1)
1.972(8)
2.510(8)
2.288(8)
2.014(8)
1.605(7)
1.619(7)
2.001
S(1)–O(3)
S(1)–O(4)
S(1)–O(5)
S(1)–O(9)
Average
1.504(8)
1.562(8)
1.452(8)
1.433(8)
1.488
S(2)–O(1)
S(2)–O(2)
S(2)–O(7)
S(2)–O(8)
Average
1.522(7)
1.459(8)
1.442(8)
1.492(8)
1.479
V–O(2)
V–O(3)
V–O(4)
V–O(6)
V–O(10)
Average
S6+ IV
1.50
S6+ IV
1.50
V5+ VI
1.92
Angle
ω
Angle
ω
O(1)VO(2)
O(1)VO(3)
O(1)VO(4)
O(1)VO(6)
O(1)VO(10)
O(2)VO(3)
O(2)VO(4)
O(2)VO(6)
O(2)VO(10)
O(3)VO(4)
O(3)VO(6)
O(3)VO(10)
O(4)VO(6)
O(4)VO(10)
O(6)VO(10)
62.7(4)
O(3)S(1)O(4)
O(3)S(1)O(5)
O(3)S(1)O(9)
O(4)S(1)O(5)
O(4)S(1)O(9)
O(5)S(1)O(9)
101.2(5)
112.7(6)
110.4(5)
109.5(5)
107.3(5)
114.7(5)
85.3(4)
139.8(3)
101.6(4)
104.7(4)
80.3(4)
84.0(4)
163.0(4)
85.9(4)
66.5(4)
92.5(4)
157.0(4)
107.4(4)
93.9(4)
105.4(4)
O(1)S(2)O(2)
O(1)S(2)O(7)
O(1)S(2)O(8)
O(2)S(2)O(7)
O(2)S(2)O(8)
O(7)S(2)O(8)
105.7(6)
108.7(5)
105.9(5)
111.0(5)
112.3(5)
112.8(6)
The italicized numbers are the sums of Shannon ionic radii [37].
Thus, the interaction in the K2O–V2O5–SO3 sysꢀ diagram (Fig. 1), according to which raising the sulfur
trioxide concentration causes the formation of a
sequence of potassiumꢀdepleted vanadates and potasꢀ
sium sulfate and then oxosulfatovanadates and potasꢀ
sium disulfate. The conversion of potassium orthovanꢀ
adate up to the maximum sulfur trioxide content of the
salt proceeds via the following reactions:
tem can be considered in terms of the Lux–Flood
acid–base approach. Potassium oxide in this system is
the base (O2– donor), vanadium(V) oxide is a comparꢀ
atively weak acid (it can show both O2– donor and O2–
acceptor properties), and sulfur trioxide is a stronger
acid than K2S2O7 (both are O2– acceptors). Therefore,
SO3 addition to the K2O–V2O5 system is like acidificaꢀ
tion. This is illustrated well by the K2O–V2O5–SO3
K3VO4 + SO3 = KVO3 + K2SO4,
(11)
(12)
K2SO4 + KVO3 + SO3 = K3VO2(SO4)2,
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 1 2011

22
KRASIL’NIKOV et al.
V2O5
K2V8O21
K2V6O16
K3V5O14
KVO3
K5V3O10
K4V2O7
K3VO4
V2O3(SO4)2
2
5
3
1
4
K2O
K2SO4
K2S2O7
SO3
Fig. 1. Phase relations in the K O–V O –SO system.
2
2
5
3
K3VO2(SO4)2 + SO3 = K3VO(SO4)3,
(13) crystalline phase K3VO2(SO4)2, causing no significant
changes in the percentage of reduced vanadium.
K3VO(SO4)3 + SO3 = KVO(SO4)2 + K2S2O7. (14)
In humid air, particularly in an atmosphere satuꢀ
rated with water vapor, K3VO2(SO4)2 undergoes hydroꢀ
lytic decomposition:
The amphoterism of V2O5 is demonstrated by reacꢀ
tion (6); its basic properties, by its reactions with
K2S2O7 and SO3, in which it behaves as an O2– donor:
K3VO2(SO4)2 + 3H2O
K2S2O7 + V2O5 = 2KVO2SO4,
2K2S2O7 + V2O5 = K4V2O3(SO4)4,
V2O5 + SO3 = V2O3(SO4)2.
(15)
(16)
(17)
(18)
=
K[VO2(SO4)(H2O)2] ⋅ H2O + K2SO4.
After being in contact with waterꢀsaturated air at
room temperature for 1 week, K3VO2(SO4)2 powder,
initially almost colorless, appears bright yellow owing
The above reactions and the phase diagram of the
K2O–V2O5–SO3 system (Fig. 1) are fairly consistent
with the chemical behavior of vanadium(V) in aqueꢀ
ous solutions, whose acidification causes a similar
sequence of vanadate conversions [36].
to the formation of K[VO2(SO4)(H2O)2] H2O (Table 1).
⋅
Glassy K3VO2(SO4)2 is more hygroscopic than its crysꢀ
talline counterpart. As a consequence, its conversion
into K[VO2(SO4)(H2O)2]
within a few hours. Heating the products of reaction
(18) above 250 initially yields Xꢀrayꢀamorphous
KVO2SO4, which then reacts with K2SO4 to form
⋅
H2O, and K2SO4 is complete
According to visual thermal analysis and DTA
data, K3VO2(SO4)2 melts incongruently in the temperꢀ
°C
ature range of 342–575 C through the peritectic reacꢀ
°
K3VO2(SO4)2
.
Therefore, in the synthesis of
KVO2SO4 (reaction (2)) can be replaced
tion K3VO2(SO4)2 = K2SO4 (s) + L. Upon rapid coolꢀ
ing, the K3VO2(SO4)2 melt turns into a glass having a
greenish yellow color due to the partial reduction of
vanadium(V) to vanadium(IV). For example, the glass
K3VO2(SO4)2
,
by the hydrated salt K[VO2(SO4)(H2O)2]
⋅
H2O.
Powdered K3VO2(SO4)2 is nearly colorless. In
obtained by melting K3VO2(SO4)2 at 600 C in a quartz polarized light under the microscope, it appears
°
tube sealed in air followed by quenching the tube in mainly as irregularly shaped colorless grains with conꢀ
water contains 2.96 wt % V4+. The vanadium(IV) conꢀ choidal fractures and as plates with moderately develꢀ
tent of the glass obtained by quenching the melt oped flattening cleavage. Optically nearꢀisotropic
between two copper plates is 3.5 wt %. Annealing at grain sections occur frequently. The refractive indexes
250–330°C
in air or oxygen converts the glass into the of K3VO2(SO4)2 are presented in Table 1. The Xꢀray
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 1 2011

K3VO2(SO4)2: FORMATION CONDITIONS
23
O8
S2
diffraction pattern of K3VO2(SO4)2 was indexed in the
monoclinic system (space group 21) with unit cell
parameters of = 10.0408(1) = 7.2312(1)
7.3821(1) = 104.457(1)°,
= 2, and V = 519.02 Å3.
P
O10
O1
O2
O7
K3
K2
a
Å
Z
,
b
Å, c =
O9
Å,
β
O6
O4
S1
V
O3
The building blocks of the K3VO2(SO4)2 structure
are [VO2(SO4)2]3– complex anions, whose spatial
arrangement for the abcꢀ and acb orientations is shown
O5
O3
V
O5
K1
O6
O6
S1
O4
O7
O9
K2
K3
K2
O5
O9
in Fig. 2; the detailed structure of the [VO2(SO4)2]3–
anion, in Fig. 3. The vanadium atom in the
[VO2(SO4)2]3– anion is in an octahedral oxygen enviꢀ
ronment consisting of two terminal oxygen atoms (V–
O(6) = 1.605(7) Å, V–O(10) = 1.619(7) Å) and four
oxygen atoms of the two chelating sulfate anions. All
V–O bonds in the VO6 octahedron are inequivalent
O1
O10
O3
S1
O4
O8
S2
O2
O6
O1
S2
V
c
O10
O7
O8
O2
K1
O9
O1
O2
O10
S2
O8
K2
O3
V
K3
O6
O4
S1
V
O5
K3
S1
O4
O7
O5 O9
O3
K2
O9
K2
O3
O6
(Table 3). The dioxovanadium group VO+2 has an
O1
O10
S1
O5
O2
O6
O1
angular (cis) configuration, in which the angle
V
O4
O7
O2
S2
O8
b
between the terminal bonds, O(6)VO(10), is 105.4(4) .
°
The shortest and longest ordinary V–O bonds are
characterized by interatomic distances of 1.972(8) and
2.510(8) Å, respectively (Table 3). The actual mean
bond length in the VO6 octahedron (2.001 Å) somewhat
exceeds the estimate reported for octahedrally coordiꢀ
nated vanadium (1.92 Å) [37]. The interatomic disꢀ
tances in either SO4 tetrahedron are also inequivalent.
The shortest bonds—S(1)–O(5), S(1)–O(9), and
S(2)–O(7)—are terminal. The mean bond lengths in
the S(1)O4 and S(2)O4 tetrahedra are 1.488 and 1.479 Å,
respectively, and are very similar to the mean bond length
in the SO4 tetrahedron: S–O = 1.50 Å [37]. The potasꢀ
O10
S2
a
O8
O4
O10
O8
O9
O6
K3
O5
V
O3
S1
O2
K1
S2
O1
O6
O4
O10
O4
O9
O10
O9
O7
O6
K3
O7
V
O5
O5
V
S1
S1
K3
O3
K2
O3
S2
O2
O2
S2
O4
O1
K1
O1
O10
O9
O6
O8
K2
O8
sium atoms bind together the [VO2(SO4)2]3– anions,
each having eight oxygen atoms in its first coordinaꢀ
tion sphere for K(1) and seven ones for K(2) and K(3).
O5
O7
V
S1
K3
K2
O4
O2
K1
b
O3
S2
O1
O6
O4
O10
O10
O9
O9
O6
K3
O1
O8
K2
O7
The observed vibrational spectra of K3VO2(SO4)2
are in good agreement with structural data. The heavy
distortion of the SO4 tetrahedron, which is due to its
coordination to the vanadium atom in the chelate
mode and the nonequivalence of the S–O distances
(Fig. 3, Table 3), entirely eliminates the vibrational
O5
V
O3
O5
V
S1
S1
O3
S2
K3
O2
O2
S2
K1
O1
O8
O8
O7
O7
c
a
degeneracy of the SO24– ion, making all of its vibraꢀ
tions both Ramanꢀ and IRꢀactive. The asymmetric
stretching band of the sulfato group, ν3(SO4), in the IR
spectrum of K3VO2(SO4)2 is split into four compoꢀ
nents and occurs in the 1170–1270 cm–1 range (Fig. 4,
Table 4). The symmetric stretching vibrations,
ν1(SO4), show themselves as strong absorption bands
3–
Fig. 2. Arrangement of [VO (SO ) ] complex anions
2
4 2
+
and
K cations in the K VO (SO ) structure: abc and acb
3 2 4 2
orientations.
VO6 octahedron. In the Raman spectrum of
K3VO2(SO4)2 (Fig. 5, Table 4), the VO+2 group manifests
at 1035 and 1020 cm–1 in the IR spectrum and weak
bands at 1039 and 1018 cm–1 in the Raman spectrum.
The symmetric and asymmetric bending bands of the
SO4 tetrahedron (ν2 and ν4) are split into two and three
components, respectively. The vibrations of the dioxoꢀ
itself as three narrow bands at 887, 921, and 939 cm–1,
whose intensity increases with an increasing waveꢀ
number. The vibrations of the ordinary vanadium–
oxygen bonds in the V–O–S bridges give rise to a
rather strong IR band and a broad mediumꢀintensity
Raman band at 520 cm–1. Such manifestation of vibraꢀ
tions of terminal V–O bonds is typical of the vibraꢀ
vanadium group VO+2 give rise to strong bands in the
875–950 cm–1 range: 943, 922, 913, and 884 cm–1.
This is in agreement with the angular geometry of the
tional spectra of K[VO2(SO4)(H2O)2]
crystal structure is also built of VO6 octahedra having
⋅
H2O, whose
dioxovanadium group (105.4°) and with the difference
between the lengths of the terminal V–O bonds in the
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 1 2011

24
KRASIL’NIKOV et al.
O(5)
O(7)
O(2)
O(3)
S(2)
S(1)
O(8)
O(9)
V
O(4)
O(1)
O(10)
O(6)
3–
Fig. 3. Detailed structure of the [VO (SO ) ] anion.
2
4 2
two short terminal bonds, V–O(1) = 1.641 Å and V– properties has been gained. This information is essenꢀ
O(2) = 1.641 Å, with a bond angle of 109.0 [16]. The
°
tial for understanding the nature of the active compoꢀ
nent of vanadium catalysts for sulfur dioxide converꢀ
sion. It has been demonstrated for the first time that
the K3VO2(SO4)2 structure is built of discrete
[VO2(SO4)2]3– complex anions. The most important
feature of these ions is that they have two short termiꢀ
nal V–O bonds and two sulfato groups chelated to
vanadium. Crystallographic data demonstrated that
vanadium in the K3VO2(SO4)2 structure is octahedrally
coordinated, corroborating the same inference drawn
from 51V NMR data for this compound [13]. The
vibrational spectra of K3VO2(SO4)2 show all features
stretching vibrations of the VO+2 group in this comꢀ
pound are characterized by fairly strong bands at 936,
901, and 876 cm–1 in the IR spectrum and at 936, 900, and
876 cm–1 in the Raman spectrum. The 400–700 cm–1
ranges of the IR absorption spectra of K3VO2(SO4)2
and K[VO2(SO4)(H2O)2] H2O, which show the bendꢀ
⋅
ing bands (ν2 and ν4) of the SO24– anion and the
stretching bands of V–O bonds with a length of about
2
Å or more, are similar in the number and positions of
absorption bands. This is likely due to the presence of
the same groups— VO6 octahedra and SO4 tetraheꢀ
dra—in the structures of these compounds.
Thus, the vanadium(V) complex K3VO2(SO4)2 has
been synthesized and radically new information on its
crystal structure and chemical and physicochemical
1200
1000
800
600
400
, cm–1
1300
1100
900
700
500
300
100
ν
Δν, cm–1
Fig. 4. IR spectrum of K VO (SO )
.
Fig. 5. Raman spectrum of K VO (SO ) .
3 2 4 2
3
2
4 2
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 56 No. 1 2011

K3VO2(SO4)2: FORMATION CONDITIONS
25
Table 4. IR and Raman frequencies (cm–1) for K3VO2(SO4)2 11. K.ꢀL. Richter and R. Mattes, Z. Anorg. Allg. Chem.
611, 158 (1992).
IR
Raman
Assignment
ν3(SO4)2–
12. A. A. Ivakin, I. G. Chufarova, M. V. Kruchinina, et al.,
Zh. Neorg. Khim. 27 (11), 2962 (1982).
13. O. B. Lapina, V. M. Mastikhin, A. A. Shubin, et al.,
1270
1252
1231
1172
1253
1232
1176
Progr. NMR Spectrosc. 24, 457 (1992).
14. A. P. Tyutyunnik, V. G. Zubkov, I. F. Berger, et al.,
Zh. Neorg. Khim. 52 (9), 1521 (2007) [Russ. J. Inorg.
Chem. 52 (9), 1424 (2007)].
1035
1020
1039
1018
ν1(SO4)2–
15. K.ꢀL. Richter and R. Mattes, Inorg. Chem. 30 (23),
943
922
913
884
939
921
ν(VO2)
4367 (1992).
16. V. G. Zubkov, A. P. Tyutyunnik, I. F. Berger, et al.,
Zh. Neorg. Khim. 52 (9), 1512 (2007) [Russ. J. Inorg.
Chem. 52 (9), 1415 (2007)].
887
672
17. S. Hahle and A. Meisel, Z. Chem., No. 7, 279 (1968).
666
ν[(V–O)–SO3]
ν4(SO4)2–
18. M. P. Glazyrin, V. N. Krasil’nikov, and A. A. Ivakin,
Zh. Neorg. Khim. 26 (10), 2682 (1981).
19. A. Altomare, M. C. Burla, B. Carrozzini, et al., J. Appl.
620
606
594
622
607
Crystallogr. 32, 339 (1999).
520
432
416
378
520
432
417
380
ν
(O–V–)
20. A. C. Larson and R. B. Von Dreele, GSAS LANSSCE,
MSꢀH805, Los Alamos Natl. Lab. Los Alamos, NM
875.
ν2(SO4)2–
δ
[(V–O)–S]
21. G. K. Boreskov, V. V. Illarionov, R. G. Ozerov, and
E. V. Kil’disheva, Zh. Obshch. Khim. 24 (1), 23 (1954).
22. S. Hähle and A. Meisel, Z. Anorg. Allg. Chem. 375 (1),
characteristic of the VO+2 , group in an angular (cis
configuration and the sulfato group chelated to the
vanadium atom.
)
24 (1970).
23. Z. Khele and A. Maizel’, Kinet. Katal. 12 (5), 1276
(1971).
24. L. N. Syrnev and R. P. Dobrev, Izv. Bolg. Akad. Nauk,
Otd. Khim. Nauk 11 (4), 869 (1969).
ACKNOWLEDGMENTS
25. S. M. Kuznetsova, L. A. Nefedova, and E. I. Dobkina,
Zh. Prikl. Khim. 70 (2), 340 (1997).
26. G. I. Petrovskaya, L. S. Gerke, and T. N. Novikova,
Khim. Prom–st, No. 12, 12 (1999).
Raman spectra were recorded at the Composition
of Substances shared facilities center, Institute of
HighꢀTemperature Electrochemistry, Ural Branch,
Russian Academy of Sciences.
27. L. A. Nefedova, E. I. Dobkina, and S. M. Kuznetsova,
Zh. Prikl. Khim. 73 (8), 1307 (2000).
28. V. N. Krasil’nikov, M. P. Glazyrin, A. A. Ivakin, et al.,
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