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The oxoantimonate K3[SbO4] crystallizes in the monoclinic space group P2/c with the Na3[BiO4] structure type. The structure contains chains of [SbO6] octahedra connected via common edges. All K and Sb atoms lie on twofold axes, i.e. 0,y,{1 \over 4} or {1 \over 2},y,{1 \over 4}.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101014342/jz1475sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270101014342/jz1475Isup2.hkl
Contains datablock I

Comment top

In the crystal structures of the known alkali metal (A) antimonates(V), [SbO6] octahedra form the important structural building blocks. In compounds with a low alkali metal content, these octahedra are connected via common edges to form complex three-dimensional channel structures (A = K: Hong, 1974; A = Rb or Cs: Hirschle et al., 2001). A similar structural chemistry is exhibited by compounds of the formula AMO3, which are known for nearly all alkali metals and which display the ilmenite or the defect pyrochlore structure. In the series of alkali-metal-rich antimonates A3SbO4, only the first (A = Li: Skakle et al., 1996) and the last (A = Cs: Hirschle & Röhr, 2000) members have been characterized by single-crystal data. Hoppe and co-workers (Schwedes & Hoppe, 1972) inferred from indexed powder patterns that Na3SbO4 is isotypic with the Li compound, and unindexed powder patterns by Duquenoy (Duquenoy, 1974; Josien & Duquenoy, 1980) indicate an isotypic relationship between the Rb and Cs compounds. Whereas the crystal structures of the Li (and Na) phase show chains of edge-sharing [SbO6] octahedra, the Cs (and Rb) compounds are characterized by isolated [SbO4]3- tetrahedra. The title compound is thus at the boundary between two structure families, which makes it a likely candidate for polytypic behaviour.

K3[SbO4] crystallizes in the monoclinic spacegroup P2/c with the Na3[BiO4] (Schwedes & Hoppe, 1972) structure type. In the crystal structure, [SbO2O4/2]3- octahedra are connected via two trans-oriented edges to form chains running parallel to the crystallographic c axis (Fig. 1); the Sb atoms are located on the twofold axis at 1/2,y,1/4.

The two terminal Sb—O bond lengths are 1.949 (6) Å (Sb—O1), whereas the bridging Sb—O bonds (Sb—O2) are significantly longer, at 2.047 (6) and 2.091 (6) Å, respectively. The O—Sb—O bond angles in the octahedra vary from 78.4 (3) to 95.7 (2)°.

The three crystallographically independent K+ cations all lie on twofold axes {K1: 1/2,y,1/4 [2(f)]; K2, K3: 0,y,1/4 [2(e)]} and are also located at the centres of the O-octahedra [K—O 2.266 (6)–2.657 (7) Å]. The structure can thus alternatively be described as a cubic close-packed arrangement of O2- ions, with the K+ and Sb5+ cations located in all the octahedral holes, i.e. an order variant of the NaCl structure.

Whereas the corresponding Li (Skakle et al., 1996) and Na (Schwedes & Hoppe, 1972) compounds are isotypic with the title compound, Cs3[SbO4] (Hirschle & Röhr, 2000) and Rb3[SbO4] (only characterized via indexed powder patterns) form structures with isolated [SbO4]3- tetrahedra and significantly shorter Sb—O bond distances. The main differences between the two structure families are also easily seen in the Raman spectra of Cs3[SbO4] and the title compound (Fig. 3): in the Cs compound, the totally symmetric stretching mode of the slightly distorted [SbO4] tetrahedra gives rise to strong bands at 710 and 722 cm-1 (Sb—O 1.78–1.89 Å). In the spectrum of K3[SbO4], the Sb—O stretching modes are shifted towards smaller wavenumbers: the band at 670 cm-1 can be assigned to the terminal Sb—O stretching mode [Sb—O1 1.949 (6) Å], while the two bands at 607 and 567 cm-1 result from the two longer bridging Sb—O2 bonds.

Related literature top

For related literature, see: Duquenoy (1974); Hirschle & Röhr (2000); Hirschle et al. (2001); Hong (1974); Josien & Duquenoy (1980); Schwedes & Hoppe (1972); Skakle et al. (1996).

Experimental top

Single crystals of K3[SbO4] were obtained from stoichiometric mixtures of K (223.7 mg, 5.72 mmol), KO2 (293.7 mg, 4.12 mmol) and Sb2O3 (482.6 mg, 1.65 mmol). The samples were heated to 975 K in corundum crucibles under an argon atmosphere, and then cooled to 575 K at a rate of 5 K h-1 and to room temperature at 15 K h-1. The X-ray powder patterns of the reaction products can be indexed on the basis of the reported single-crystal data, but show additional weak reflections that cannot be assigned to any known phase. The colourless hygroscopic crystals of the title compound were handled in a dry box and mounted in capillaries filled with dry oil. The room temperature Raman spectra of single crystals of K3[SbO4] and Cs3[SbO4], sealed in Lindemann capillaries, were recorded with a Raman microscope attached to an FT spectrometer (Bruker IFS66V).

Refinement top

Because of the slightly higher values of the atomic displacement parameters of the K atoms, the site occupancy of the three positions was refined for testing purposes, converging on the ideal value of 0.5 to within experimental error. The maximum difference peak of 3.32 e Å-3 lies 0.83 Å from Sb1 and may be attributed to residual absorption errors.

Computing details top

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP (Johnson, 1968) and DRAWxtl (Finger & Kroeker, 1999); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. A view of the chain of [SbO6] octahedra in K3SbO4 with 75% probability displacement ellipsoids.
[Figure 2] Fig. 2. Views of the unit cell of the crystal structure of K3[SbO4] in two orientations, (a) ? and (b) ?. Light grey spheres denote K, light grey octahedra denote [SbO6] and dark grey spheres denote O.
[Figure 3] Fig. 3. The Raman spectra of K3SbO4 and Cs3SbO4.
Tripotassium oxoantimonate(V) top
Crystal data top
K3[SbO4]Z = 2
Mr = 303.05F(000) = 280
Monoclinic, P2/cDx = 5.153 Mg m3
a = 5.7971 (12) ÅMo Kα radiation, λ = 0.71070 Å
b = 6.5933 (14) ŵ = 10.14 mm1
c = 5.4179 (12) ÅT = 293 K
β = 109.394 (4)°Irregular, colourless
V = 195.33 (7) Å30.20 × 0.15 × 0.10 mm
Data collection top
Bruker SMART CCD area-detector
diffractometer
468 independent reflections
Radiation source: fine-focus sealed tube422 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.033
ω scansθmax = 28.3°, θmin = 3.1°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 67
Tmin = 0.192, Tmax = 0.363k = 87
1160 measured reflectionsl = 76
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.048 w = 1/[σ2(Fo2) + (0.0848P)2 + 0.0284P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.122(Δ/σ)max < 0.001
S = 1.24Δρmax = 3.32 e Å3
468 reflectionsΔρmin = 2.83 e Å3
40 parametersExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.128 (16)
Crystal data top
K3[SbO4]V = 195.33 (7) Å3
Mr = 303.05Z = 2
Monoclinic, P2/cMo Kα radiation
a = 5.7971 (12) ŵ = 10.14 mm1
b = 6.5933 (14) ÅT = 293 K
c = 5.4179 (12) Å0.20 × 0.15 × 0.10 mm
β = 109.394 (4)°
Data collection top
Bruker SMART CCD area-detector
diffractometer
468 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
422 reflections with I > 2σ(I)
Tmin = 0.192, Tmax = 0.363Rint = 0.033
1160 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.04840 parameters
wR(F2) = 0.1220 restraints
S = 1.24Δρmax = 3.32 e Å3
468 reflectionsΔρmin = 2.83 e Å3
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
xyzUiso*/Ueq
Sb10.50000.86977 (8)0.25000.0110 (4)
O10.2733 (11)0.3322 (9)0.5407 (12)0.0151 (11)
O20.3045 (11)0.0986 (8)0.0005 (11)0.0121 (11)
K10.50000.3832 (4)0.25000.0385 (10)
K20.00000.1253 (5)0.25000.0437 (12)
K30.00000.6099 (6)0.25000.0516 (13)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Sb10.0151 (6)0.0086 (6)0.0084 (5)0.0000.0027 (3)0.000
O10.018 (3)0.016 (2)0.009 (2)0.002 (2)0.001 (2)0.002 (2)
O20.015 (2)0.016 (2)0.004 (2)0.000 (2)0.0011 (19)0.0006 (18)
K10.045 (2)0.034 (2)0.036 (2)0.0000.0133 (18)0.000
K20.046 (2)0.037 (2)0.043 (3)0.0000.007 (2)0.000
K30.055 (3)0.051 (3)0.054 (3)0.0000.024 (2)0.000
Geometric parameters (Å, º) top
Sb1—O1i1.949 (6)K1—O1xiii2.387 (6)
Sb1—O1ii1.949 (6)K1—K1ii3.116 (3)
Sb1—O2iii2.047 (6)K1—K1iii3.116 (3)
Sb1—O2iv2.047 (6)K1—Sb1ii3.1813 (15)
Sb1—O2v2.091 (6)K1—Sb1iii3.1813 (15)
Sb1—O2vi2.091 (6)K1—K3ii3.2446 (5)
Sb1—K1ii3.1813 (15)K2—O1xiv2.279 (6)
Sb1—K1iii3.1813 (15)K2—O2xi2.355 (6)
Sb1—Sb1vii3.2074 (8)K2—O2xv2.355 (6)
Sb1—Sb1viii3.2075 (8)K2—O2xiv2.561 (6)
Sb1—K13.208 (3)K2—K2xvi3.173 (3)
Sb1—K2ii3.2444 (5)K2—K2xi3.173 (3)
O1—Sb1ii1.949 (6)K2—K33.195 (7)
O1—K1ii2.355 (6)K2—K3ix3.2229 (19)
O1—K12.387 (6)K2—K3xii3.2229 (19)
O1—K22.279 (6)K2—Sb1ii3.2444 (5)
O1—K3ix2.266 (6)K3—O1i2.266 (6)
O1—K32.585 (7)K3—O1ix2.266 (6)
O2—Sb1iii2.047 (6)K3—O1xiv2.585 (7)
O2—Sb1x2.091 (6)K3—O2iv2.657 (7)
O2—K12.370 (6)K3—O2xii2.657 (7)
O2—K2xi2.355 (6)K3—K3ix3.072 (4)
O2—K22.561 (6)K3—K3xii3.072 (4)
O2—K3xii2.657 (7)K3—K2ix3.2229 (19)
K1—O1ii2.354 (6)K3—K2xii3.2229 (19)
K1—O1i2.354 (6)K3—K1ii3.2446 (5)
K1—O2xiii2.370 (6)
O1i—Sb1—O1ii93.8 (3)K2—O1—K192.1 (2)
O1i—Sb1—O2iii95.7 (2)K1ii—O1—K182.2 (2)
O1ii—Sb1—O2iii92.3 (2)Sb1ii—O1—K3175.4 (3)
O1i—Sb1—O2iv92.3 (2)K3ix—O1—K378.27 (19)
O1ii—Sb1—O2iv95.7 (2)K2—O1—K381.8 (2)
O2iii—Sb1—O2iv168.3 (3)K1ii—O1—K382.0 (2)
O1i—Sb1—O2v90.1 (3)K1—O1—K381.9 (2)
O1ii—Sb1—O2v170.2 (2)Sb1iii—O2—Sb1x101.6 (3)
O2iii—Sb1—O2v78.4 (3)Sb1iii—O2—K2xi99.0 (2)
O2iv—Sb1—O2v93.1 (2)Sb1x—O2—K2xi93.5 (2)
O1i—Sb1—O2vi170.2 (2)Sb1iii—O2—K191.9 (2)
O1ii—Sb1—O2vi90.1 (3)Sb1x—O2—K198.6 (2)
O2iii—Sb1—O2vi93.1 (2)K2xi—O2—K1161.8 (3)
O2iv—Sb1—O2vi78.4 (3)Sb1iii—O2—K2166.7 (3)
O2v—Sb1—O2vi87.6 (3)Sb1x—O2—K291.7 (2)
Sb1ii—O1—K3ix105.8 (3)K2xi—O2—K280.28 (18)
Sb1ii—O1—K2100.0 (2)K1—O2—K285.8 (2)
K3ix—O1—K290.3 (2)Sb1iii—O2—K3xii90.45 (19)
Sb1ii—O1—K1ii95.9 (2)Sb1x—O2—K3xii167.9 (3)
K3ix—O1—K1ii89.8 (2)K2xi—O2—K3xii85.2 (2)
K2—O1—K1ii163.4 (3)K1—O2—K3xii80.18 (19)
Sb1ii—O1—K193.9 (2)K2—O2—K3xii76.26 (18)
K3ix—O1—K1159.4 (3)
Symmetry codes: (i) x, y+1, z1/2; (ii) x+1, y+1, z+1; (iii) x+1, y+1, z; (iv) x, y+1, z+1/2; (v) x, y+1, z; (vi) x+1, y+1, z+1/2; (vii) x+1, y+2, z+1; (viii) x+1, y+2, z; (ix) x, y+1, z+1; (x) x, y1, z; (xi) x, y, z; (xii) x, y+1, z; (xiii) x+1, y, z+1/2; (xiv) x, y, z+1/2; (xv) x, y, z+1/2; (xvi) x, y, z+1.

Experimental details

Crystal data
Chemical formulaK3[SbO4]
Mr303.05
Crystal system, space groupMonoclinic, P2/c
Temperature (K)293
a, b, c (Å)5.7971 (12), 6.5933 (14), 5.4179 (12)
β (°) 109.394 (4)
V3)195.33 (7)
Z2
Radiation typeMo Kα
µ (mm1)10.14
Crystal size (mm)0.20 × 0.15 × 0.10
Data collection
DiffractometerBruker SMART CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.192, 0.363
No. of measured, independent and
observed [I > 2σ(I)] reflections
1160, 468, 422
Rint0.033
(sin θ/λ)max1)0.666
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.122, 1.24
No. of reflections468
No. of parameters40
Δρmax, Δρmin (e Å3)3.32, 2.83

Computer programs: SMART (Bruker, 1999), SAINT (Bruker, 1999), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP (Johnson, 1968) and DRAWxtl (Finger & Kroeker, 1999), SHELXL97.

Selected geometric parameters (Å, º) top
Sb1—O1i1.949 (6)O1—K3v2.266 (6)
Sb1—O2ii2.047 (6)O1—K32.585 (7)
Sb1—O2iii2.091 (6)O2—K12.370 (6)
O1—K1iv2.355 (6)O2—K2vi2.355 (6)
O1—K12.387 (6)O2—K22.561 (6)
O1—K22.279 (6)O2—K3vii2.657 (7)
O1i—Sb1—O1iv93.8 (3)O1iv—Sb1—O2iii170.2 (2)
O1i—Sb1—O2ii95.7 (2)O2ii—Sb1—O2iii78.4 (3)
O1iv—Sb1—O2ii92.3 (2)O2viii—Sb1—O2iii93.1 (2)
O2ii—Sb1—O2viii168.3 (3)O2iii—Sb1—O2ix87.6 (3)
O1i—Sb1—O2iii90.1 (3)
Symmetry codes: (i) x, y+1, z1/2; (ii) x+1, y+1, z; (iii) x, y+1, z; (iv) x+1, y+1, z+1; (v) x, y+1, z+1; (vi) x, y, z; (vii) x, y+1, z; (viii) x, y+1, z+1/2; (ix) x+1, y+1, z+1/2.
 

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