β-K(VO2)2(PO4)

Ezzine Yahmed, S.; Ayed, M.; Zid, M.F.; Driss, A.

doi:10.1107/S1600536812049884

β-K(VO₂)₂(PO₄)

S. Ezzine Yahmed, M. Ayed, M. F. Zid and A. Driss

A new vanadium oxide, potassium bis(dioxovanadyl) phosphate, β-K(VO₂)₂(PO₄), has been synthesized by a solid-state reaction. In the title compound, the [V₂PO₈] framework is built up from infinite pyramidal [V₂O₈]_∞ and [VPO₇]_∞ chains linked together by V—O—P bridges, leading to a three-dimensional framework which delimits two types of intersecting tunnels running along [100] and [010] in which the four unique K⁺ ions, showing coordination numbers of nine and ten, are located.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536812049884/fi2128sup1.cif Contains datablocks I, global
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536812049884/fi2128Isup2.hkl Contains datablock I

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Key indicators

Single-crystal X-ray study
T = 298 K
Mean (P-O) = 0.002 Å
R factor = 0.030
wR factor = 0.086
Data-to-parameter ratio = 13.1

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          3
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         35

Alert level G
PLAT004_ALERT_5_G Info: Polymeric Structure Found with Dimension .          3
PLAT005_ALERT_5_G No _iucr_refine_instructions_details  in the CIF          ?
PLAT042_ALERT_1_G Calc. and Reported MoietyFormula Strings  Differ          ?
PLAT045_ALERT_1_G Calculated and Reported Z Differ by ............       0.25 Ratio
PLAT793_ALERT_4_G The Model has Chirality at P1      (Verify) ....          S
PLAT793_ALERT_4_G The Model has Chirality at P2      (Verify) ....          R
PLAT793_ALERT_4_G The Model has Chirality at P3      (Verify) ....          R
PLAT793_ALERT_4_G The Model has Chirality at P4      (Verify) ....          R
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600         13

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   2 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   9 ALERT level G = General information/check it is not something unexpected

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   5 ALERT type 4 Improvement, methodology, query or suggestion
   2 ALERT type 5 Informative message, check

Comment top

Materials developed in the A—V—X—O systems (where A=Alkali, X= P or As) and having open mixed anionic frameworks (uni, bi, and three-dimensional) have interesting physical properties, especially catalytic (Pierini et al., 2005) and ionic conductivity (Daidouh et al., 1997). This has led to the synthesis, by a solid state reaction, of a new form of divanadium phosphate KV₂PO₈. The asymmetric unit, (Fig. 1) of the title compound, is built up from four double pyramidal units V₂O₉ (consisting of distorted vertices-sharing VO₅ trigonal-bipyramids encountered in A₆V₆P₆O₃₁ (A= Rb and K (Benhamada et al., 1991; Leclaire & Raveau, 2006)) interconnected by corner-sharing PO₄ single tetrahedra. The junction of each kind of V₂O₉ unit by V–O–V bridges leads to two types of infinite chains with formula (V₂O₈)_∞. The first kind is parallel to the b axis where two successive pairs of pyramids have their apical oxygen atoms pointing towards the same direction (Fig. 2a). The second type is parallel to the a axis (Fig. 3) and two successive pairs of pyramids have their apical oxygen atoms pointing towards opposite directions. The compound can be described as a connection between the (V₂O₈)_∞ chains by vertex sharing of VO₅ pentahedra and PO₄ tetrahedra. Projections of the structure along the a and b axis show that the VO₅ and PO₄ polyhedra alternate along the a axis to form infinite chains (VPO₇)_∞ in which vanadium polyhedra share an oxygen with one neighboring chain, leading to double chains (V₂P₂O₁₂)_∞. Adjacent (V₂O₈)_∞ chains running along b are connected by double chains of vanadyl phosphate via corner sharing. The structure is depicted in (Fig. 4) and (Fig. 5) and can be denoted as a three-dimensional framework with two types of tunnels running along a and b axis where the monovalent cations K⁺ are located.

The bond valence sums (BVS) calculations using the empirical formula of Brown (Brown & Altermatt, 1985) assuming cations bonds give the values: P1(5.045), P2(4.991), P3(5.013), P4(5.027), V1(5.106), V2(5.066), V3(5.028), V4(5.127), V5(5.056), V6(5.081), V7(5.087), V8(5.115), K1(1.029), K2(0.991), K3(1.031) and K4(1.004) which verify coordination geometries and oxidation states for each atom.

The comparison of our material with those found in the literature reveals the presence of infinite chains (VPO₇)_∞, (V₂P₂O₁₂)_∞ and (V₂O₈)_∞ in the noncentrosymmetric compound with similar formulation α-KV₂PO₈ (Berrah et al., 1999). However, two successive pairs of pyramids have their apical oxygen in a trans-position leading to the sequence "cis-trans-trans-cis" (Fig. 2b). This leads to eight-sided tunnels that are smaller than those encountered in our structure. (V₂O₈)_∞ chains similar to those found in our phase where two successive pairs of pyramids have their apical oxygen atoms pointing towards the same direction have already been observed for the ammonium hydrogenophosphate α-NH₄VO₂PO₃OH (Amoros & Le Bail, 1992). Materials K₃V₃As₂O₁₄ (Ezzine et al., 2009) and A₂VP₂O₈ (A = Rb, Cs (Lii & Wang, 1989) and Na, Rb (Daidouh et al., 1998)) also contain chains (VXO₇)_∞ (X = As or P) whose linkage form infinite layers of type (V₂As₂O₁₄)_∞ and (VP₂O₈)_∞. The junction of these chains along the three directions of the cell edges leads to three-dimensional structures with large tunnels for α-KV₂PO₈ and K₃V₃As₂O₁₄ compounds. As far as the series of A₂VP₂O₈ (A= Alkali) compounds is concerned, they form by P–O–P bridges two-dimensional structures, characterized by the presence of interlayer space where the cations are located.

Related literature top

For α-K(VO₂)₂(PO₄), see: Berrah et al. (1999). For background to the physico-chemical properties of related compounds, see: Daidouh et al. (1997); Pierini & Lombardo (2005). For details of structurally related compounds, see: Leclaire & Raveau (2006); Amoros & Le Bail (1992); Lii & Wang (1989); Daidouh et al. (1998); Benhamada et al. (1991). For the preparation, see: Ezzine et al. (2009). For bond-valence sums, see: Brown & Altermatt (1985).

Experimental top

In order to obtain a new phosphate isotypic with K₃V₃As₂O₁₄ (Ezzine et al., 2009), KNO₃ (Fluka, 60415), NH₄VO₃ (Riedel-De Haën, 12739) and NH₄H₂PO₄ (Scharlau, AM0335) were first mixed in the molar ratio 3:3:2 and heated at 573 K to decompose the ammonium phosphate and the nitrate. In a second step, the resulting mixture was crushed then heated at 793 K for two days, cooled slowly (5°C/24 h) down to 743 K and finally quenched to room temperature. From the resulting product, well-shaped crystals of various sizes, of satisfactory quality for analysis by X-ray diffraction, were retrieved. A yellow ochre parallelpipedic crystal was chosen from the selection for the determination of cell parameters.

Structure description top

Computing details top

Data collection: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); cell refinement: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1998); software used to prepare material for publication: WinGX (Farrugia, 2012).

Figures top

	Fig. 1. Asymmetric unit of β-K(VO₂)₂(PO₄). Displacement ellipsoids are drawn at the 50% probability level. Symmetry codes:(i) x+1, y, z; (ii) - x+1, -y+2, -z+1; (iii) x-1, y, z; (iv) -x+1, -y+1, -z+1; (v) x, y, z+1; (vi) x-1, y, z+1; (vii) x, y, z-1.
	Fig. 2. Representation of the first type of infinite chains (V₂O₈)_∞ showing the disposition of apical oxygen atoms: (a) in cis-cis position in β-K(VO₂)₂(PO₄). (b) in cis-cis-trans-trans position in α-K(VO₂)₂(PO₄).
	Fig. 3. Representation of the second type of (V₂O₈)_∞ chains, running along a.
	Fig. 4. Projection of the structure of β-K(VO₂)₂(PO₄) along a showing S shaped tunnels.
	Fig. 5. Projection of the structure of β-K(VO₂)₂(PO₄) along b showing 'Pacman' shaped tunnels.

Potassium bis(dioxovanadyl) phosphate top

Crystal data top

K(VO₂)₂(PO₄)	Z = 8
M_r = 299.95	F(000) = 1152
Triclinic, P1	D_x = 3.020 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.7438 (8) Å	Cell parameters from 25 reflections
b = 13.889 (2) Å	θ = 10–16°
c = 21.201 (3) Å	µ = 3.71 mm⁻¹
α = 70.89 (2)°	T = 298 K
β = 89.55 (3)°	Prism, yellow ochre
γ = 88.66 (3)°	0.28 × 0.18 × 0.12 mm
V = 1319.5 (4) Å³

Data collection top

Enraf–Nonius CAD-4 diffractometer	4828 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.021
Graphite monochromator	θ_max = 27.0°, θ_min = 2.0°
ω/2θ scans	h = −6→1
Absorption correction: ψ scan (North et al., 1968)	k = −17→17
T_min = 0.447, T_max = 0.668	l = −27→27
7567 measured reflections	2 standard reflections every 120 min
5673 independent reflections	intensity decay: 1.2%

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.030	w = 1/[σ²(F_o²) + (0.045P)² + 1.4475P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.086	(Δ/σ)_max = 0.001
S = 1.08	Δρ_max = 0.80 e Å⁻³
5673 reflections	Δρ_min = −0.50 e Å⁻³
434 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0177 (5)

Crystal data top

K(VO₂)₂(PO₄)	γ = 88.66 (3)°
M_r = 299.95	V = 1319.5 (4) Å³
Triclinic, P1	Z = 8
a = 4.7438 (8) Å	Mo Kα radiation
b = 13.889 (2) Å	µ = 3.71 mm⁻¹
c = 21.201 (3) Å	T = 298 K
α = 70.89 (2)°	0.28 × 0.18 × 0.12 mm
β = 89.55 (3)°

Data collection top

Enraf–Nonius CAD-4 diffractometer	4828 reflections with I > 2σ(I)
Absorption correction: ψ scan (North et al., 1968)	R_int = 0.021
T_min = 0.447, T_max = 0.668	2 standard reflections every 120 min
7567 measured reflections	intensity decay: 1.2%
5673 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.030	434 parameters
wR(F²) = 0.086	0 restraints
S = 1.08	Δρ_max = 0.80 e Å⁻³
5673 reflections	Δρ_min = −0.50 e Å⁻³

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
P1	0.81894 (16)	0.82998 (6)	0.62044 (4)	0.00927 (16)
P2	0.30877 (16)	0.66561 (6)	0.38286 (4)	0.00846 (16)
P3	0.69764 (16)	0.95394 (6)	0.88110 (4)	0.00847 (16)
P4	0.18695 (16)	0.55208 (6)	0.11864 (4)	0.00897 (16)
V1	0.67895 (11)	0.62518 (4)	0.74349 (2)	0.01025 (12)
V2	0.20740 (11)	0.84522 (4)	0.97612 (2)	0.00914 (12)
V3	0.67812 (11)	0.86795 (4)	0.75923 (3)	0.01073 (12)
V4	0.33078 (11)	0.63012 (4)	0.24341 (3)	0.01087 (12)
V5	0.79712 (10)	0.68009 (4)	0.47752 (2)	0.00898 (12)
V6	0.32962 (11)	0.87164 (4)	0.25925 (3)	0.01096 (12)
V7	0.30088 (11)	0.82752 (4)	0.52064 (2)	0.00904 (12)
V8	0.70261 (11)	0.65479 (4)	0.01947 (2)	0.00902 (12)
K1	0.19194 (17)	0.53056 (6)	0.62537 (4)	0.02600 (18)
K2	0.80918 (17)	0.84200 (7)	0.12683 (4)	0.02642 (18)
K3	0.25658 (18)	0.65377 (7)	0.87178 (4)	0.02692 (19)
K4	0.74706 (18)	0.97341 (6)	0.36973 (4)	0.02608 (19)
O1	0.6015 (5)	0.78815 (16)	0.46573 (11)	0.0130 (4)
O2	0.4024 (4)	0.74851 (16)	0.96467 (11)	0.0132 (4)
O3	0.8822 (4)	0.93237 (16)	0.94288 (10)	0.0116 (4)
O4	0.1257 (4)	0.85042 (17)	0.59847 (11)	0.0146 (4)
O5	0.1243 (4)	0.62663 (16)	0.44482 (10)	0.0113 (4)
O6	0.9010 (4)	0.75197 (16)	0.02434 (11)	0.0135 (4)
O7	0.1026 (5)	0.72520 (17)	0.52599 (11)	0.0135 (4)
O8	0.8785 (4)	0.55572 (16)	0.09744 (11)	0.0145 (5)
O9	0.6199 (5)	0.65051 (17)	0.40334 (11)	0.0146 (4)
O10	0.2347 (5)	0.77905 (16)	0.34598 (11)	0.0143 (5)
O11	0.3322 (5)	0.86573 (18)	0.03997 (11)	0.0184 (5)
O12	0.3868 (4)	0.94798 (16)	0.90171 (11)	0.0136 (4)
O13	0.2543 (5)	0.93608 (16)	0.16436 (11)	0.0129 (4)
O14	0.6717 (5)	0.59606 (18)	0.54165 (11)	0.0177 (5)
O15	0.7832 (6)	0.71576 (17)	0.65851 (11)	0.0201 (5)
O16	0.3734 (4)	0.57915 (17)	0.05664 (11)	0.0141 (4)
O17	0.7492 (5)	0.89548 (16)	0.66473 (11)	0.0131 (4)
O18	0.2579 (5)	0.59998 (16)	0.33811 (11)	0.0126 (4)
O19	0.2327 (6)	0.62756 (17)	0.15666 (11)	0.0196 (5)
O20	0.1780 (5)	0.92122 (18)	0.46105 (12)	0.0195 (5)
O21	0.8267 (5)	0.62017 (18)	0.96030 (12)	0.0184 (5)
O22	0.7748 (5)	0.87717 (16)	0.84469 (11)	0.0143 (5)
O23	0.6303 (5)	0.86329 (17)	0.55904 (11)	0.0143 (4)
O24	0.2538 (5)	0.44138 (16)	0.16220 (11)	0.0131 (4)
O25	0.2320 (5)	0.98015 (16)	0.27381 (11)	0.0174 (5)
O26	0.7750 (5)	0.74426 (16)	0.77524 (11)	0.0163 (5)
O27	0.2304 (5)	0.75295 (16)	0.22901 (11)	0.0175 (5)
O28	0.7767 (5)	0.51742 (16)	0.72784 (11)	0.0166 (5)
O29	0.3424 (5)	0.62895 (19)	0.74222 (12)	0.0219 (5)
O30	0.6654 (5)	0.8693 (2)	0.25991 (13)	0.0236 (5)
O31	0.3413 (5)	0.86967 (19)	0.76068 (12)	0.0215 (5)
O32	0.6666 (5)	0.6285 (2)	0.24292 (13)	0.0231 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
P1	0.0107 (4)	0.0107 (3)	0.0072 (3)	−0.0017 (3)	0.0015 (3)	−0.0039 (3)
P2	0.0090 (4)	0.0101 (3)	0.0066 (3)	−0.0001 (3)	−0.0001 (3)	−0.0032 (3)
P3	0.0086 (4)	0.0090 (3)	0.0070 (3)	−0.0001 (3)	0.0002 (3)	−0.0016 (3)
P4	0.0105 (4)	0.0087 (3)	0.0069 (3)	−0.0003 (3)	−0.0015 (3)	−0.0013 (3)
V1	0.0148 (3)	0.0087 (2)	0.0071 (2)	−0.00055 (19)	−0.00053 (19)	−0.00236 (19)
V2	0.0078 (2)	0.0107 (2)	0.0082 (2)	0.00032 (18)	−0.00125 (18)	−0.00212 (19)
V3	0.0153 (3)	0.0088 (2)	0.0081 (2)	−0.00139 (19)	0.00208 (19)	−0.00273 (19)
V4	0.0157 (3)	0.0089 (2)	0.0081 (2)	−0.00129 (19)	−0.0007 (2)	−0.00267 (19)
V5	0.0072 (2)	0.0115 (2)	0.0083 (2)	−0.00063 (18)	0.00118 (18)	−0.00344 (19)
V6	0.0161 (3)	0.0088 (2)	0.0082 (2)	−0.00082 (19)	−0.0007 (2)	−0.00290 (19)
V7	0.0077 (2)	0.0114 (2)	0.0083 (2)	0.00012 (18)	−0.00159 (18)	−0.00353 (19)
V8	0.0081 (2)	0.0101 (2)	0.0083 (2)	−0.00074 (18)	0.00148 (19)	−0.00222 (19)
K1	0.0215 (4)	0.0238 (4)	0.0267 (4)	−0.0012 (3)	0.0034 (3)	−0.0002 (3)
K2	0.0228 (4)	0.0352 (4)	0.0265 (4)	0.0008 (3)	−0.0044 (3)	−0.0173 (4)
K3	0.0252 (4)	0.0351 (4)	0.0268 (4)	−0.0088 (3)	0.0098 (3)	−0.0186 (4)
K4	0.0262 (4)	0.0217 (4)	0.0252 (4)	−0.0035 (3)	−0.0088 (3)	−0.0003 (3)
O1	0.0112 (10)	0.0162 (11)	0.0130 (10)	0.0018 (8)	−0.0012 (8)	−0.0069 (9)
O2	0.0106 (10)	0.0134 (10)	0.0139 (11)	−0.0001 (8)	0.0009 (8)	−0.0023 (8)
O3	0.0109 (10)	0.0149 (10)	0.0085 (10)	0.0027 (8)	−0.0021 (8)	−0.0032 (8)
O4	0.0077 (10)	0.0244 (12)	0.0149 (11)	−0.0013 (9)	0.0013 (8)	−0.0110 (9)
O5	0.0090 (10)	0.0150 (10)	0.0085 (10)	0.0021 (8)	0.0012 (8)	−0.0024 (8)
O6	0.0092 (10)	0.0120 (10)	0.0169 (11)	−0.0007 (8)	−0.0019 (9)	−0.0014 (8)
O7	0.0099 (10)	0.0176 (11)	0.0160 (11)	−0.0025 (8)	0.0016 (9)	−0.0094 (9)
O8	0.0083 (10)	0.0172 (11)	0.0142 (11)	−0.0006 (8)	0.0006 (8)	0.0001 (9)
O9	0.0095 (11)	0.0224 (11)	0.0156 (11)	0.0013 (9)	−0.0015 (9)	−0.0114 (9)
O10	0.0217 (12)	0.0102 (10)	0.0103 (10)	0.0013 (9)	−0.0003 (9)	−0.0025 (8)
O11	0.0184 (12)	0.0234 (12)	0.0137 (11)	−0.0025 (9)	−0.0029 (9)	−0.0063 (9)
O12	0.0082 (10)	0.0146 (10)	0.0137 (11)	0.0003 (8)	−0.0015 (8)	0.0011 (8)
O13	0.0190 (12)	0.0105 (10)	0.0087 (10)	−0.0037 (8)	0.0014 (9)	−0.0022 (8)
O14	0.0149 (11)	0.0218 (12)	0.0135 (11)	−0.0046 (9)	0.0032 (9)	−0.0015 (9)
O15	0.0389 (15)	0.0112 (11)	0.0105 (11)	−0.0044 (10)	0.0079 (10)	−0.0040 (9)
O16	0.0095 (10)	0.0193 (11)	0.0122 (10)	−0.0033 (8)	0.0012 (8)	−0.0030 (9)
O17	0.0187 (12)	0.0112 (10)	0.0097 (10)	0.0000 (8)	0.0032 (9)	−0.0041 (8)
O18	0.0176 (11)	0.0128 (10)	0.0078 (10)	−0.0019 (8)	−0.0010 (8)	−0.0037 (8)
O19	0.0354 (14)	0.0116 (11)	0.0119 (11)	−0.0016 (10)	−0.0066 (10)	−0.0038 (9)
O20	0.0195 (12)	0.0199 (12)	0.0161 (12)	0.0051 (9)	−0.0034 (10)	−0.0021 (9)
O21	0.0183 (12)	0.0234 (12)	0.0150 (11)	0.0029 (9)	0.0039 (9)	−0.0085 (9)
O22	0.0214 (12)	0.0105 (10)	0.0113 (11)	0.0003 (9)	0.0010 (9)	−0.0041 (8)
O23	0.0105 (11)	0.0223 (11)	0.0117 (10)	−0.0019 (9)	−0.0019 (8)	−0.0076 (9)
O24	0.0197 (12)	0.0095 (10)	0.0090 (10)	0.0015 (8)	−0.0022 (9)	−0.0017 (8)
O25	0.0343 (14)	0.0103 (10)	0.0075 (10)	−0.0020 (9)	0.0023 (9)	−0.0028 (8)
O26	0.0294 (13)	0.0107 (10)	0.0086 (10)	0.0004 (9)	−0.0008 (9)	−0.0029 (8)
O27	0.0334 (14)	0.0109 (10)	0.0075 (10)	−0.0016 (9)	−0.0031 (10)	−0.0017 (8)
O28	0.0317 (13)	0.0099 (10)	0.0081 (10)	−0.0020 (9)	0.0023 (9)	−0.0027 (8)
O29	0.0166 (12)	0.0270 (13)	0.0201 (13)	0.0027 (10)	−0.0033 (10)	−0.0049 (10)
O30	0.0173 (13)	0.0282 (13)	0.0248 (13)	0.0003 (10)	−0.0031 (10)	−0.0082 (11)
O31	0.0165 (12)	0.0269 (13)	0.0213 (13)	−0.0015 (10)	0.0030 (10)	−0.0080 (10)
O32	0.0155 (12)	0.0304 (14)	0.0243 (13)	−0.0037 (10)	0.0018 (10)	−0.0098 (11)

Geometric parameters (Å, º) top

P1—O23	1.521 (3)	V7—O7	1.695 (2)
P1—O4ⁱ	1.529 (2)	V7—O23	1.917 (2)
P1—O17	1.536 (2)	V7—O4	1.955 (2)
P1—O15	1.539 (2)	V7—O1	2.010 (3)
P2—O5	1.524 (2)	V8—O21^vii	1.588 (2)
P2—O9	1.532 (2)	V8—O6	1.694 (2)
P2—O18	1.539 (2)	V8—O16	1.918 (3)
P2—O10	1.546 (2)	V8—O8	1.950 (3)
P3—O3	1.523 (2)	V8—O2^vii	2.005 (3)
P3—O12	1.531 (2)	K1—O18^viii	2.771 (3)
P3—O13ⁱⁱ	1.537 (2)	K1—O14	2.852 (3)
P3—O22	1.544 (2)	K1—O7	2.856 (3)
P4—O16	1.525 (3)	K1—O28ⁱⁱⁱ	2.885 (3)
P4—O8ⁱⁱⁱ	1.529 (2)	K1—O9^iv	2.895 (3)
P4—O19	1.537 (2)	K1—O14ⁱⁱⁱ	2.996 (3)
P4—O24	1.539 (2)	K1—O32^iv	3.008 (4)
V1—O29	1.596 (2)	K1—O18^iv	3.097 (3)
V1—O28	1.690 (2)	K1—O29	3.287 (3)
V1—O15	1.899 (3)	K2—O13ⁱ	2.763 (3)
V1—O24^iv	1.934 (2)	K2—O6	2.866 (3)
V1—O26	2.041 (2)	K2—O11	2.873 (3)
V2—O11^v	1.593 (2)	K2—O27ⁱ	2.901 (4)
V2—O2	1.694 (2)	K2—O12ⁱⁱ	2.910 (3)
V2—O3ⁱⁱⁱ	1.927 (3)	K2—O11ⁱ	3.037 (3)
V2—O12	1.952 (3)	K2—O30	3.038 (3)
V2—O6^vi	2.008 (3)	K2—O13	3.124 (3)
V3—O31	1.598 (2)	K2—O32	3.256 (4)
V3—O26	1.692 (2)	K3—O21ⁱⁱⁱ	2.704 (3)
V3—O22	1.918 (2)	K3—O2	2.802 (3)
V3—O17	1.941 (2)	K3—O24^iv	2.848 (3)
V3—O25ⁱⁱ	2.048 (2)	K3—O8^iv	2.853 (3)
V4—O32	1.592 (2)	K3—O29	2.903 (3)
V4—O27	1.689 (2)	K3—O24^viii	2.988 (3)
V4—O19	1.912 (2)	K3—O26ⁱⁱⁱ	3.040 (4)
V4—O18	1.942 (2)	K3—O31	3.181 (4)
V4—O28^iv	2.014 (2)	K3—O26	3.193 (4)
V5—O14	1.595 (3)	K3—O21	3.240 (3)
V5—O1	1.694 (2)	K4—O20ⁱ	2.744 (3)
V5—O5ⁱ	1.926 (2)	K4—O1	2.806 (3)
V5—O9	1.952 (2)	K4—O4ⁱⁱ	2.822 (3)
V5—O7ⁱ	2.009 (3)	K4—O17ⁱⁱ	2.889 (3)
V6—O30	1.593 (3)	K4—O31ⁱⁱ	2.933 (3)
V6—O25	1.688 (2)	K4—O17^ix	2.977 (3)
V6—O10	1.924 (3)	K4—O25ⁱ	3.041 (3)
V6—O13	1.948 (2)	K4—O30	3.147 (3)
V6—O27	2.021 (2)	K4—O25	3.171 (3)
V7—O20	1.590 (3)	K4—O20	3.264 (4)

O23—P1—O4ⁱ	109.01 (14)	O22—V3—O25ⁱⁱ	83.48 (11)
O23—P1—O17	109.42 (14)	O17—V3—O25ⁱⁱ	76.99 (11)
O4ⁱ—P1—O17	106.61 (14)	O32—V4—O27	105.91 (15)
O23—P1—O15	110.17 (15)	O32—V4—O19	103.89 (15)
O4ⁱ—P1—O15	109.90 (17)	O27—V4—O19	95.54 (12)
O17—P1—O15	111.63 (13)	O32—V4—O18	100.53 (14)
O5—P2—O9	109.44 (14)	O27—V4—O18	90.26 (12)
O5—P2—O18	108.38 (13)	O19—V4—O18	152.23 (11)
O9—P2—O18	106.84 (14)	O32—V4—O28^iv	105.13 (15)
O5—P2—O10	109.41 (14)	O27—V4—O28^iv	148.24 (12)
O9—P2—O10	111.43 (16)	O19—V4—O28^iv	83.39 (11)
O18—P2—O10	111.26 (13)	O18—V4—O28^iv	77.61 (11)
O3—P3—O12	109.42 (13)	O14—V5—O1	106.78 (13)
O3—P3—O13ⁱⁱ	108.56 (14)	O14—V5—O5ⁱ	110.53 (13)
O12—P3—O13ⁱⁱ	106.81 (15)	O1—V5—O5ⁱ	142.54 (11)
O3—P3—O22	109.33 (14)	O14—V5—O9	103.24 (12)
O12—P3—O22	111.71 (15)	O1—V5—O9	93.29 (12)
O13ⁱⁱ—P3—O22	110.93 (13)	O5ⁱ—V5—O9	81.56 (10)
O16—P4—O8ⁱⁱⁱ	109.06 (13)	O14—V5—O7ⁱ	96.23 (12)
O16—P4—O19	109.92 (14)	O1—V5—O7ⁱ	93.05 (11)
O8ⁱⁱⁱ—P4—O19	110.26 (15)	O5ⁱ—V5—O7ⁱ	79.85 (10)
O16—P4—O24	108.94 (14)	O9—V5—O7ⁱ	156.79 (10)
O8ⁱⁱⁱ—P4—O24	106.65 (15)	O30—V6—O25	105.48 (15)
O19—P4—O24	111.92 (13)	O30—V6—O10	103.21 (15)
O29—V1—O28	105.95 (15)	O25—V6—O10	96.97 (11)
O29—V1—O15	104.16 (15)	O30—V6—O13	101.01 (15)
O28—V1—O15	95.75 (11)	O25—V6—O13	90.43 (12)
O29—V1—O24^iv	100.43 (15)	O10—V6—O13	151.70 (10)
O28—V1—O24^iv	90.45 (11)	O30—V6—O27	103.95 (14)
O15—V1—O24^iv	151.84 (11)	O25—V6—O27	149.67 (12)
O29—V1—O26	102.98 (14)	O10—V6—O27	83.24 (10)
O28—V1—O26	150.24 (12)	O13—V6—O27	76.87 (10)
O15—V1—O26	83.72 (10)	O20—V7—O7	107.46 (13)
O24^iv—V1—O26	77.53 (10)	O20—V7—O23	111.76 (13)
O11^v—V2—O2	106.92 (13)	O7—V7—O23	140.64 (12)
O11^v—V2—O3ⁱⁱⁱ	110.30 (13)	O20—V7—O4	101.96 (12)
O2—V2—O3ⁱⁱⁱ	142.66 (11)	O7—V7—O4	94.01 (12)
O11^v—V2—O12	103.25 (12)	O23—V7—O4	81.21 (10)
O2—V2—O12	93.04 (11)	O20—V7—O1	95.37 (13)
O3ⁱⁱⁱ—V2—O12	81.45 (11)	O7—V7—O1	93.37 (11)
O11^v—V2—O6^vi	96.50 (12)	O23—V7—O1	80.05 (10)
O2—V2—O6^vi	92.90 (11)	O4—V7—O1	158.15 (10)
O3ⁱⁱⁱ—V2—O6^vi	80.19 (10)	O21^vii—V8—O6	107.21 (13)
O12—V2—O6^vi	156.70 (10)	O21^vii—V8—O16	110.63 (12)
O31—V3—O26	105.43 (15)	O6—V8—O16	142.02 (11)
O31—V3—O22	102.93 (14)	O21^vii—V8—O8	102.02 (12)
O26—V3—O22	97.24 (12)	O6—V8—O8	93.61 (11)
O31—V3—O17	101.01 (14)	O16—V8—O8	81.75 (11)
O26—V3—O17	90.49 (12)	O21^vii—V8—O2^vii	95.70 (12)
O22—V3—O17	151.81 (10)	O6—V8—O2^vii	93.36 (10)
O31—V3—O25ⁱⁱ	102.47 (15)	O16—V8—O2^vii	79.98 (10)
O26—V3—O25ⁱⁱ	151.14 (12)	O8—V8—O2^vii	158.08 (10)

Symmetry codes: (i) x+1, y, z; (ii) −x+1, −y+2, −z+1; (iii) x−1, y, z; (iv) −x+1, −y+1, −z+1; (v) x, y, z+1; (vi) x−1, y, z+1; (vii) x, y, z−1; (viii) −x, −y+1, −z+1; (ix) −x+2, −y+2, −z+1.

Experimental details

Crystal data
Chemical formula	K(VO₂)₂(PO₄)
M_r	299.95
Crystal system, space group	Triclinic, P1
Temperature (K)	298
a, b, c (Å)	4.7438 (8), 13.889 (2), 21.201 (3)
α, β, γ (°)	70.89 (2), 89.55 (3), 88.66 (3)
V (Å³)	1319.5 (4)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	3.71
Crystal size (mm)	0.28 × 0.18 × 0.12

Data collection
Diffractometer	Enraf–Nonius CAD-4
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.447, 0.668
No. of measured, independent and observed [I > 2σ(I)] reflections	7567, 5673, 4828
R_int	0.021
(sin θ/λ)_max (Å⁻¹)	0.638

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.030, 0.086, 1.08
No. of reflections	5673
No. of parameters	434
Δρ_max, Δρ_min (e Å⁻³)	0.80, −0.50

Computer programs: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 1998), WinGX (Farrugia, 2012).

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