Potassium ditin(IV) tris­[phosphate(V)], KSn2(PO4)3

Zhang, H.J.

doi:10.1107/S1600536811035604

inorganic compounds

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Volume 67| Part 10| October 2011| Page i51

https://doi.org/10.1107/S1600536811035604

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Potassium ditin(IV) tris[phosphate(V)], KSn₂(PO₄)₃

Hui Ju Zhang ^a ^*

^aDepartment of Physics and Chemistry, Henan Polytechnic University, Jiaozuo, Henan 454000, People's Republic of China
^*Correspondence e-mail: zhj@hpu.edu.cn

(Received 16 June 2011; accepted 1 September 2011; online 14 September 2011)

The title compound, KSn₂(PO₄)₃, belongs to the NASICON-type family of phosphates with the space group R $[\overline{3}]$ . Its structure is constructed by very regular [with P—O distances ranging from 1.513 (6) to 1.522 (6) Å] PO₄ tetrahedra and SnO₆ octahedra on the 3. axis, which are linked by O atoms, forming an [Sn₂(PO₄)₃] framework. The K atoms occupy the $[\overline{3}]$ . axis sites and are located in the voids of this arrangement. The crystal studied was a merohedral twin with twin law (010 100 00 $[\overline{1}]$ ) and a component ratio of 0.580 (7):0.420 (7).

Related literature

For related NASICON-type compounds, see: Alamo & Rodrigo (1992 ); Boilot et al. (1987 ); Boujelben et al. (2007 ); Zatovskii et al. (2006 ); Zhao et al. (2011 ).

Experimental

Crystal data

KSn₂(PO₄)₃
M_r = 561.39
Trigonal, $[R \overline 3]$
a = 8.3381 (1) Å
c = 23.5508 (3) Å
V = 1417.98 (3) Å³
Z = 6
Mo Kα radiation
μ = 6.30 mm⁻¹
T = 296 K
0.20 × 0.05 × 0.05 mm

Data collection

Bruker SMART 1K CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1997 ) T_min = 0.366, T_max = 0.744
2168 measured reflections
597 independent reflections
591 reflections with I > 2σ(I)
R_int = 0.098

Refinement

R[F² > 2σ(F²)] = 0.053
wR(F²) = 0.137
S = 1.24
597 reflections
58 parameters
Δρ_max = 2.23 e Å⁻³
Δρ_min = −2.99 e Å⁻³

Data collection: SMART (Bruker, 1997); cell refinement: SMART; data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2004 ); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536811035604/fi2111sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536811035604/fi2111Isup2.hkl

checkCIF report

Comment top

In the past, the family of AM₂(PO₄)₃ (A = alkali metals; M = Ti, Zr, Ge, Sn) compounds with the NASICON-type (Na₃Zr₂Si₂PO₁₂: Boilot, et al., 1987) structure have been extensively investigated for their intriguing properities, such as the ionic conductivity properities which may due to the complex and subtle interactions between NASICON framework and mobile ions. The NASICON-type structure with a flexible three-dimensional framework of PO₄ tetrahedra sharing comers with MO₆ octahedra, is amenable to a wide variety of chemical substitutions at the various crystallographic positions, thus yielding a large number of closely related compounds, such as NaFeNb(PO₄)₃ (Zatovskii, et al., 2006) and K₂Ca₂(SO₄)₃ (Boujelben, et al., 2007). In order to inrich this family of compounds, we synthesis the compound KSn₂(PO₄)₃ by the high-temperature reaction and determine the crystal structure from single-crystal X-ray diffraction analysis.KSn₂(PO₄)₃ is isostructure with Na (Alamo & Rodrigo, 1992) and Rb (Zhao et al., 2011) analog crystals which crystallizes in the trigonal space group R-3.

A projection of the crystal structure of KSn₂(PO₄)₃ is given in Fig. 2. It is characterized by the presence of PO₄ tetrahedra and SnO₆ octahedra, linked by sharing corner O atoms, to establish a three-dimentional [Sn₂(PO₄)₃] framework. Furthermore, this framwork delimits two types of channels in which the K atoms are located to compensate the negative charges. The PO₄ tetrahedra are quite regular, with the P–O distance ranging from 1.513 (6) to 1.522 (6) Å, while the SnO₆ octahedra is quite regular too, with the Sn–O distance ranging from 2.003 (6) to 2.045 (6) Å.

Related literature top

For related NASICON-type compounds, see: Alamo & Rodrigo (1992); Boilot et al. (1987); Boujelben et al. (2007); Zatovskii et al. (2006); Zhao et al. (2011).

Experimental top

Compound KSn₂(PO₄)₃ has been prepared by a high-temperature method in air. A powder mixture of K₂CO₃, SnO₂ and NH₄H₂PO₄ in the molar ratio of K: Sn: P = 15: 1: 15 was first ground in an agate mortar and then transferred to a platinum crucible. The sample was gradually heated in air at 1173 K for 24 h. After that, the intermediate product was slowly cooled to 773 K at the rate of 2 K h^-1, and finally quenched to room temperature. The obtained crystals were colorless with a prismatic shape.

Structure description top

For related NASICON-type compounds, see: Alamo & Rodrigo (1992); Boilot et al. (1987); Boujelben et al. (2007); Zatovskii et al. (2006); Zhao et al. (2011).

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SMART (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2004); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1. The expanded asymmetric unit of KSn₂(PO₄)₃ showing the coordination environments of the P and Sn atoms. The displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) -x + y, -x, z; (ii) -y, x-y, z; (iii) y - 1/3, -x + y - 2/3, -z + 1/3; (v) -x - 1/3, -y + 1/3, -z + 1/3; (vi) -x, -y + 1, -z; (vii) x-y + 1, x + 1, -z; (viii) y, -x + y, -z; (x) -y + 1, x-y + 1, z.]

Fig. 2. View of the crystal structure of KSn₂(PO₄)₃ along [010]. PO₄ and SnO₆ units are given in the polyhedral representation.

Potassium ditin(IV) tris[phosphate(V)] top

Crystal data top

KSn₂(PO₄)₃	D_x = 3.945 Mg m⁻³
M_r = 561.39	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3	Cell parameters from 256 reflections
Hall symbol: -R 3	θ = 2.6–23.6°
a = 8.3381 (1) Å	µ = 6.30 mm⁻¹
c = 23.5508 (3) Å	T = 296 K
V = 1417.98 (3) Å³	Prism, colourless
Z = 6	0.20 × 0.05 × 0.05 mm
F(000) = 1560

Data collection top

Bruker SMART 1K CCD diffractometer	597 independent reflections
Radiation source: fine-focus sealed tube	591 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.098
\ scans	θ_max = 25.7°, θ_min = 3.0°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −10→10
T_min = 0.366, T_max = 0.744	k = −10→10
2168 measured reflections	l = −17→28

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)] = 0.053	w = 1/[σ²(F_o²) + (0.0764P)² + 11.5796P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.137	(Δ/σ)_max < 0.001
S = 1.24	Δρ_max = 2.23 e Å⁻³
597 reflections	Δρ_min = −2.99 e Å⁻³
58 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0063 (7)

Crystal data top

KSn₂(PO₄)₃	Z = 6
M_r = 561.39	Mo Kα radiation
Trigonal, R3	µ = 6.30 mm⁻¹
a = 8.3381 (1) Å	T = 296 K
c = 23.5508 (3) Å	0.20 × 0.05 × 0.05 mm
V = 1417.98 (3) Å³

Data collection top

Bruker SMART 1K CCD diffractometer	597 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 1997)	591 reflections with I > 2σ(I)
T_min = 0.366, T_max = 0.744	R_int = 0.098
2168 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.053	0 restraints
wR(F²) = 0.137	w = 1/[σ²(F_o²) + (0.0764P)² + 11.5796P] where P = (F_o² + 2F_c²)/3
S = 1.24	Δρ_max = 2.23 e Å⁻³
597 reflections	Δρ_min = −2.99 e Å⁻³
58 parameters

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
Sn1	0.0000	0.0000	0.15357 (4)	0.0107 (5)
Sn2	0.3333	0.6667	0.01858 (4)	0.0103 (5)
K1	0.3333	0.6667	0.1667	0.0273 (12)
K2	0.0000	0.0000	0.0000	0.0378 (14)
P3	−0.0441 (3)	0.3326 (4)	0.08384 (9)	0.0117 (6)
O5	−0.0732 (11)	0.1435 (9)	0.1006 (2)	0.0174 (15)
O7	−0.1043 (9)	0.4149 (9)	0.1310 (2)	0.0154 (14)
O8	−0.1477 (9)	0.3069 (10)	0.0284 (3)	0.0208 (15)
O9	0.1599 (8)	0.4650 (8)	0.0738 (2)	0.0140 (15)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Sn1	0.0111 (6)	0.0111 (6)	0.0099 (6)	0.0056 (3)	0.000	0.000
Sn2	0.0108 (5)	0.0108 (5)	0.0093 (6)	0.0054 (3)	0.000	0.000
K1	0.0332 (17)	0.0332 (17)	0.015 (2)	0.0166 (9)	0.000	0.000
K2	0.050 (2)	0.050 (2)	0.014 (2)	0.0248 (11)	0.000	0.000
P3	0.0115 (12)	0.0118 (11)	0.0109 (11)	0.0052 (9)	0.0006 (9)	0.0003 (9)
O5	0.024 (4)	0.018 (4)	0.017 (3)	0.015 (3)	0.001 (3)	0.001 (2)
O7	0.023 (3)	0.009 (3)	0.016 (3)	0.009 (3)	0.006 (3)	0.000 (3)
O8	0.020 (4)	0.032 (4)	0.011 (3)	0.013 (3)	−0.003 (3)	0.002 (3)
O9	0.016 (3)	0.014 (3)	0.012 (3)	0.006 (3)	0.000 (2)	−0.003 (2)

Geometric parameters (Å, º) top

Sn1—O5ⁱ	2.023 (6)	K1—O7^iv	3.282 (7)
Sn1—O5ⁱⁱ	2.023 (6)	K1—O7^xii	3.282 (7)
Sn1—O5	2.023 (6)	K1—O7^xi	3.282 (7)
Sn1—O7ⁱⁱⁱ	2.032 (6)	K1—O7^x	3.282 (7)
Sn1—O7^iv	2.033 (6)	K2—O5	2.853 (6)
Sn1—O7^v	2.033 (6)	K2—O5^xiii	2.854 (6)
Sn1—K2	3.6167 (9)	K2—O5ⁱ	2.854 (6)
Sn2—O8^vi	2.003 (6)	K2—O5^viii	2.854 (6)
Sn2—O8^vii	2.003 (6)	K2—O5ⁱⁱ	2.854 (6)
Sn2—O8^viii	2.003 (6)	K2—O5^xiv	2.854 (6)
Sn2—O9^ix	2.045 (6)	K2—O8^xiii	3.416 (7)
Sn2—O9	2.045 (6)	K2—O8ⁱ	3.416 (7)
Sn2—O9^x	2.045 (6)	K2—O8^viii	3.416 (7)
Sn2—K1	3.4876 (9)	K2—O8ⁱⁱ	3.416 (7)
K1—O9^xi	2.696 (6)	K2—O8^xiv	3.416 (7)
K1—O9^xii	2.696 (6)	K2—O8	3.416 (7)
K1—O9^iv	2.696 (6)	P3—O9	1.513 (6)
K1—O9^ix	2.696 (6)	P3—O7	1.516 (6)
K1—O9	2.696 (6)	P3—O8	1.520 (6)
K1—O9^x	2.696 (6)	P3—O5	1.522 (6)
K1—O7^ix	3.282 (7)	O7—Sn1^v	2.033 (6)
K1—O7	3.282 (7)	O8—Sn2^vi	2.003 (6)

O5ⁱ—Sn1—O5ⁱⁱ	85.9 (2)	O9—K1—O7^x	76.59 (17)
O5ⁱ—Sn1—O5	85.9 (2)	O9^x—K1—O7^x	46.76 (15)
O5ⁱⁱ—Sn1—O5	85.9 (2)	O7^ix—K1—O7^x	113.67 (8)
O5ⁱ—Sn1—O7ⁱⁱⁱ	90.7 (2)	O7—K1—O7^x	113.67 (8)
O5ⁱⁱ—Sn1—O7ⁱⁱⁱ	92.1 (2)	O7^iv—K1—O7^x	66.33 (8)
O5—Sn1—O7ⁱⁱⁱ	176.2 (2)	O7^xii—K1—O7^x	66.33 (8)
O5ⁱ—Sn1—O7^iv	92.1 (2)	O7^xi—K1—O7^x	180.00 (14)
O5ⁱⁱ—Sn1—O7^iv	176.2 (2)	O5—K2—O5^xiii	122.2 (2)
O5—Sn1—O7^iv	90.7 (2)	O5—K2—O5ⁱ	57.8 (2)
O7ⁱⁱⁱ—Sn1—O7^iv	91.2 (2)	O5^xiii—K2—O5ⁱ	180.0 (6)
O5ⁱ—Sn1—O7^v	176.2 (2)	O5—K2—O5^viii	122.2 (2)
O5ⁱⁱ—Sn1—O7^v	90.7 (2)	O5^xiii—K2—O5^viii	57.8 (2)
O5—Sn1—O7^v	92.1 (2)	O5ⁱ—K2—O5^viii	122.2 (2)
O7ⁱⁱⁱ—Sn1—O7^v	91.2 (2)	O5—K2—O5ⁱⁱ	57.8 (2)
O7^iv—Sn1—O7^v	91.2 (2)	O5^xiii—K2—O5ⁱⁱ	122.2 (2)
O5ⁱ—Sn1—K2	51.89 (17)	O5ⁱ—K2—O5ⁱⁱ	57.8 (2)
O5ⁱⁱ—Sn1—K2	51.89 (17)	O5^viii—K2—O5ⁱⁱ	180.0 (3)
O5—Sn1—K2	51.89 (17)	O5—K2—O5^xiv	180.000 (1)
O7ⁱⁱⁱ—Sn1—K2	124.44 (17)	O5^xiii—K2—O5^xiv	57.8 (2)
O7^iv—Sn1—K2	124.43 (17)	O5ⁱ—K2—O5^xiv	122.2 (2)
O7^v—Sn1—K2	124.43 (17)	O5^viii—K2—O5^xiv	57.8 (2)
O8^vi—Sn2—O8^vii	92.4 (2)	O5ⁱⁱ—K2—O5^xiv	122.2 (2)
O8^vi—Sn2—O8^viii	92.4 (2)	O5—K2—O8^xiii	83.25 (18)
O8^vii—Sn2—O8^viii	92.4 (2)	O5^xiii—K2—O8^xiii	44.79 (16)
O8^vi—Sn2—O9^ix	84.6 (3)	O5ⁱ—K2—O8^xiii	135.21 (16)
O8^vii—Sn2—O9^ix	100.0 (3)	O5^viii—K2—O8^xiii	95.98 (17)
O8^viii—Sn2—O9^ix	167.3 (3)	O5ⁱⁱ—K2—O8^xiii	84.02 (17)
O8^vi—Sn2—O9	100.0 (3)	O5^xiv—K2—O8^xiii	96.75 (18)
O8^vii—Sn2—O9	167.3 (3)	O5—K2—O8ⁱ	96.75 (18)
O8^viii—Sn2—O9	84.6 (3)	O5^xiii—K2—O8ⁱ	135.21 (16)
O9^ix—Sn2—O9	83.8 (2)	O5ⁱ—K2—O8ⁱ	44.79 (16)
O8^vi—Sn2—O9^x	167.3 (3)	O5^viii—K2—O8ⁱ	84.02 (17)
O8^vii—Sn2—O9^x	84.6 (3)	O5ⁱⁱ—K2—O8ⁱ	95.98 (17)
O8^viii—Sn2—O9^x	100.0 (3)	O5^xiv—K2—O8ⁱ	83.25 (18)
O9^ix—Sn2—O9^x	83.8 (2)	O8^xiii—K2—O8ⁱ	180.0 (3)
O9—Sn2—O9^x	83.8 (2)	O5—K2—O8^viii	84.02 (17)
O8^vi—Sn2—K1	123.56 (18)	O5^xiii—K2—O8^viii	96.75 (18)
O8^vii—Sn2—K1	123.56 (18)	O5ⁱ—K2—O8^viii	83.25 (18)
O8^viii—Sn2—K1	123.56 (18)	O5^viii—K2—O8^viii	44.79 (16)
O9^ix—Sn2—K1	50.48 (17)	O5ⁱⁱ—K2—O8^viii	135.21 (16)
O9—Sn2—K1	50.48 (17)	O5^xiv—K2—O8^viii	95.98 (17)
O9^x—Sn2—K1	50.48 (17)	O8^xiii—K2—O8^viii	116.25 (7)
O9^xi—K1—O9^xii	60.9 (2)	O8ⁱ—K2—O8^viii	63.75 (7)
O9^xi—K1—O9^iv	60.9 (2)	O5—K2—O8ⁱⁱ	95.98 (17)
O9^xii—K1—O9^iv	60.9 (2)	O5^xiii—K2—O8ⁱⁱ	83.25 (18)
O9^xi—K1—O9^ix	119.1 (2)	O5ⁱ—K2—O8ⁱⁱ	96.75 (18)
O9^xii—K1—O9^ix	119.1 (2)	O5^viii—K2—O8ⁱⁱ	135.21 (16)
O9^iv—K1—O9^ix	179.999 (1)	O5ⁱⁱ—K2—O8ⁱⁱ	44.79 (16)
O9^xi—K1—O9	119.1 (2)	O5^xiv—K2—O8ⁱⁱ	84.02 (17)
O9^xii—K1—O9	179.999 (1)	O8^xiii—K2—O8ⁱⁱ	63.75 (7)
O9^iv—K1—O9	119.1 (2)	O8ⁱ—K2—O8ⁱⁱ	116.25 (7)
O9^ix—K1—O9	60.9 (2)	O8^viii—K2—O8ⁱⁱ	180.0 (3)
O9^xi—K1—O9^x	179.999 (1)	O5—K2—O8^xiv	135.21 (16)
O9^xii—K1—O9^x	119.1 (2)	O5^xiii—K2—O8^xiv	95.98 (17)
O9^iv—K1—O9^x	119.1 (2)	O5ⁱ—K2—O8^xiv	84.02 (17)
O9^ix—K1—O9^x	60.9 (2)	O5^viii—K2—O8^xiv	96.75 (18)
O9—K1—O9^x	60.9 (2)	O5ⁱⁱ—K2—O8^xiv	83.25 (18)
O9^xi—K1—O7^ix	103.41 (17)	O5^xiv—K2—O8^xiv	44.79 (16)
O9^xii—K1—O7^ix	72.93 (16)	O8^xiii—K2—O8^xiv	116.25 (7)
O9^iv—K1—O7^ix	133.24 (16)	O8ⁱ—K2—O8^xiv	63.75 (7)
O9^ix—K1—O7^ix	46.76 (16)	O8^viii—K2—O8^xiv	116.25 (7)
O9—K1—O7^ix	107.07 (16)	O8ⁱⁱ—K2—O8^xiv	63.75 (7)
O9^x—K1—O7^ix	76.59 (17)	O5—K2—O8	44.79 (16)
O9^xi—K1—O7	72.93 (16)	O5^xiii—K2—O8	84.02 (17)
O9^xii—K1—O7	133.23 (16)	O5ⁱ—K2—O8	95.98 (17)
O9^iv—K1—O7	103.41 (17)	O5^viii—K2—O8	83.25 (18)
O9^ix—K1—O7	76.59 (17)	O5ⁱⁱ—K2—O8	96.75 (18)
O9—K1—O7	46.76 (16)	O5^xiv—K2—O8	135.21 (16)
O9^x—K1—O7	107.07 (16)	O8^xiii—K2—O8	63.75 (7)
O7^ix—K1—O7	113.68 (8)	O8ⁱ—K2—O8	116.25 (7)
O9^xi—K1—O7^iv	76.59 (17)	O8^viii—K2—O8	63.75 (7)
O9^xii—K1—O7^iv	107.07 (16)	O8ⁱⁱ—K2—O8	116.25 (7)
O9^iv—K1—O7^iv	46.76 (16)	O8^xiv—K2—O8	180.0
O9^ix—K1—O7^iv	133.24 (16)	O9—P3—O7	106.8 (4)
O9—K1—O7^iv	72.93 (16)	O9—P3—O8	108.8 (4)
O9^x—K1—O7^iv	103.41 (17)	O7—P3—O8	113.5 (4)
O7^ix—K1—O7^iv	180.0	O9—P3—O5	109.6 (4)
O7—K1—O7^iv	66.32 (8)	O7—P3—O5	111.2 (3)
O9^xi—K1—O7^xii	107.07 (16)	O8—P3—O5	106.9 (4)
O9^xii—K1—O7^xii	46.76 (16)	O9—P3—K1	44.3 (2)
O9^iv—K1—O7^xii	76.59 (17)	O7—P3—K1	67.0 (3)
O9^ix—K1—O7^xii	103.41 (17)	O8—P3—K1	142.9 (3)
O9—K1—O7^xii	133.24 (16)	O5—P3—K1	106.8 (3)
O9^x—K1—O7^xii	72.93 (16)	O9—P3—K2	88.0 (2)
O7^ix—K1—O7^xii	66.32 (8)	O7—P3—K2	160.5 (3)
O7—K1—O7^xii	180.0	O8—P3—K2	71.8 (3)
O7^iv—K1—O7^xii	113.68 (8)	O5—P3—K2	50.5 (2)
O9^xi—K1—O7^xi	46.76 (16)	K1—P3—K2	121.08 (7)
O9^xii—K1—O7^xi	76.59 (17)	P3—O5—Sn1	146.4 (4)
O9^iv—K1—O7^xi	107.07 (16)	P3—O5—K2	105.3 (3)
O9^ix—K1—O7^xi	72.93 (16)	Sn1—O5—K2	94.2 (2)
O9—K1—O7^xi	103.41 (17)	P3—O7—Sn1^v	136.9 (4)
O9^x—K1—O7^xi	133.24 (16)	P3—O7—K1	87.9 (3)
O7^ix—K1—O7^xi	66.33 (8)	Sn1^v—O7—K1	128.9 (2)
O7—K1—O7^xi	66.33 (8)	P3—O8—Sn2^vi	151.1 (4)
O7^iv—K1—O7^xi	113.67 (8)	P3—O8—K2	83.2 (3)
O7^xii—K1—O7^xi	113.67 (8)	Sn2^vi—O8—K2	124.2 (3)
O9^xi—K1—O7^x	133.24 (16)	P3—O9—Sn2	140.7 (4)
O9^xii—K1—O7^x	103.41 (17)	P3—O9—K1	112.7 (3)
O9^iv—K1—O7^x	72.93 (16)	Sn2—O9—K1	93.7 (2)
O9^ix—K1—O7^x	107.07 (16)

Symmetry codes: (i) −x+y, −x, z; (ii) −y, x−y, z; (iii) y−1/3, −x+y−2/3, −z+1/3; (iv) x−y+2/3, x+1/3, −z+1/3; (v) −x−1/3, −y+1/3, −z+1/3; (vi) −x, −y+1, −z; (vii) x−y+1, x+1, −z; (viii) y, −x+y, −z; (ix) −x+y, −x+1, z; (x) −y+1, x−y+1, z; (xi) y−1/3, −x+y+1/3, −z+1/3; (xii) −x+2/3, −y+4/3, −z+1/3; (xiii) x−y, x, −z; (xiv) −x, −y, −z.

Experimental details

Crystal data
Chemical formula	KSn₂(PO₄)₃
M_r	561.39
Crystal system, space group	Trigonal, R3
Temperature (K)	296
a, c (Å)	8.3381 (1), 23.5508 (3)
V (Å³)	1417.98 (3)
Z	6
Radiation type	Mo Kα
µ (mm⁻¹)	6.30
Crystal size (mm)	0.20 × 0.05 × 0.05

Data collection
Diffractometer	Bruker SMART 1K CCD
Absorption correction	Multi-scan (SADABS; Bruker, 1997)
T_min, T_max	0.366, 0.744
No. of measured, independent and observed [I > 2σ(I)] reflections	2168, 597, 591
R_int	0.098
(sin θ/λ)_max (Å⁻¹)	0.611

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.053, 0.137, 1.24
No. of reflections	597
No. of parameters	58
	w = 1/[σ²(F_o²) + (0.0764P)² + 11.5796P] where P = (F_o² + 2F_c²)/3
Δρ_max, Δρ_min (e Å⁻³)	2.23, −2.99

Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2004), SHELXTL (Sheldrick, 2008).

References

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