RbSn2(PO4)3, a NASICON-type phosphate

Zhao, D.; Li, F.F.; Qiu, S.; Jiao, J.; Ren, J.

doi:10.1107/S1600536811014310

inorganic compounds

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Volume 67| Part 5| May 2011| Page i32

doi:10.1107/S1600536811014310

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RbSn₂(PO₄)₃, a NASICON-type phosphate

Dan Zhao,^a ^* FeiFei Li,^a Shen Qiu,^a Jiali Jiao ^a and Junran Ren ^a

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

(Received 13 March 2011; accepted 16 April 2011; online 29 April 2011)

The title compound, rubidium ditin(IV) tris(phosphate), RbSn₂(PO₄)₃, belongs to the NASICON-type family of phosphates and crystallizes in the space group R $[\overline{3}]$ . The structure is composed of PO₄ tetrahedra (1 symmetry) and two slightly distorted SnO₆ octahedra, both with 3. symmetry, which are interlinked through corner-sharing O atoms to form a ³_∞[Sn₂(PO₄)₃]⁻ framework. The Rb⁺ cations are located on threefold inversion axes in the voids of this framework and exhibit a coordination number of 12. The crystal studied was twinned by merohedry with a component ratio of 0.503:0.497.

Related literature

For related NASICON-type compounds, see: Boilot et al. (1987 ); Boujelben et al. (2007 ); Duhlev (1994 ); Zatovskii et al. (2006 ); Zhao et al. (2011 ).

Experimental

Crystal data

RbSn₂(PO₄)₃
M_r = 607.76
Trigonal, $[R \overline 3]$
a = 8.340 (4) Å
c = 24.007 (8) Å
V = 1446.1 (6) Å³
Z = 6
Mo Kα radiation
μ = 10.76 mm⁻¹
T = 293 K
0.20 × 0.05 × 0.05 mm

Data collection

Rigaku Mercury70 CCD diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ) T_min = 0.222, T_max = 0.615
3765 measured reflections
742 independent reflections
711 reflections with I > 2σ(I)
R_int = 0.036

Refinement

R[F² > 2σ(F²)] = 0.026
wR(F²) = 0.043
S = 1.16
742 reflections
57 parameters
Δρ_max = 0.65 e Å⁻³
Δρ_min = −0.73 e Å⁻³

Table 1
Selected bond lengths (Å)

Sn1—O2	2.015 (4)
Sn1—O3ⁱ	2.033 (4)
P1—O2	1.523 (4)
P1—O1	1.529 (4)
P1—O3	1.533 (4)
P1—O4	1.537 (4)
Symmetry code: (i) y, -x+y, -z.

Data collection: CrystalClear (Rigaku, 2004 ); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ) and PLATON (Spek, 2009 ); 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: 10.1107/S1600536811014310/wm2466sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811014310/wm2466Isup2.hkl

checkCIF report

Comment top

In recent years, the AM₂(PO₄)₃ (A = alkali metal; M = Ti, Zr, Ge, Sn) family with NASICON (Na₃Zr₂Si₂PO₁₂; Boilot et al., 1987) -type structures attracted a growing interest due to their intriguing properities, e.g. ionic conductivity of the A cations located in the voids of the three-dimensional NASICON-type framework. This framework is composed of isolated PO₄ tetrahedra sharing corners with MO₆ octahedra (Fig. 1), and 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), Rb₂Ca₂(SO₄)₃ (Boujelben et al., 2007) or Al_0.5Nb_1.5(PO₄)₃ (Zhao et al., 2011). In order to augment this family of compounds, we prepared crystals of the compound RbSn₂(PO₄)₃ using a solid state reaction route. Unlike the analogous Ti compound RbTi₂(PO₄)₃ which crystallises in space group R3c (Duhlev, 1994), RbSn₂(PO₄)₃ crystallises in space group R3.

A projection of the crystal structure of RbSn₂(PO₄)₃ is given in Fig. 2. It is characterized by the presence of isolated PO₄ tetrahedra (1 symmetry) and two different SnO₆ octahedra (both 3. symmetry), linked by sharing corner O atoms, to establish a three-dimensional ³_∞[Sn₂(PO₄)₃]^- framework. This framwork delimits two types of channels in which the twelve-coordinate Rb⁺ atoms (site symmetry 3.) are located to compensate the negative charges. The PO₄ tetrahedra are quite regular, with P–O distances ranging from 1.523 (4) to 1.537 (4) Å. The two SnO₆ octahedra exhibit Sn—O distances ranging from 2.015 (4) to 2.033 (4) Å.

Related literature top

For related NASICON-type compounds, see: Boilot et al. (1987); Boujelben et al. (2007); Duhlev (1994); Zatovskii et al. (2006); Zhao et al. (2011).

Experimental top

Single crystals of RbSn₂(PO₄)₃ have been prepared by a high-temperature method in air. A powder mixture of RbNO₃, SnO₂ and NH₄H₂PO₄ in the molar ratio of Rb: Sn: P = 10: 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 673 K at the rate of 2 K h^-1. It was kept at 673 K for another 10 h and then quenched to room temperature. The obtained crystals were colorless with a prismatic shape.

Computing details top

Data collection: CrystalClear (Rigaku, 2004); cell refinement: CrystalClear (Rigaku, 2004); data reduction: CrystalClear (Rigaku, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008) and PLATON (Spek, 2009); 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 RbSn₂(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) -y, x-y, z; (ii) -x + y, -x, z; (iii) 1 - y, x-y, z; (iv) 1 - x + y, 1 - x, z; (v) 1 - x, 1 - y, -z; (vi) 1 + x-y, x, -z; (vii) y, -x + y, -z; (Viii) -1/3 + y, 1/3 - x + y, 1/3 - z; (ix) 2/3 - x, 1/3 - y, 1/3 - z; (x) -1/3 + x-y, -2/3 + x, 1/3 - z.]

Fig. 2. View of the crystal structure of RbSn₂(PO₄)₃ along [100]. PO₄ and SnO₆ units are given in the polyhedral representation.

rubidium ditin(IV) tris(phosphate) top

Crystal data top

RbSn₂(PO₄)₃	D_x = 4.187 Mg m⁻³
M_r = 607.76	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3	Cell parameters from 1316 reflections
Hall symbol: -R 3	θ = 2.6–27.5°
a = 8.340 (4) Å	µ = 10.76 mm⁻¹
c = 24.007 (8) Å	T = 293 K
V = 1446.1 (6) Å³	Prism, colourless
Z = 6	0.20 × 0.05 × 0.05 mm
F(000) = 1668

Data collection top

Rigaku Mercury70 CCD diffractometer	742 independent reflections
Radiation source: fine-focus sealed tube	711 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.036
Detector resolution: 14.6306 pixels mm^-1	θ_max = 27.5°, θ_min = 2.6°
ω scans	h = −9→10
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	k = −10→10
T_min = 0.222, T_max = 0.615	l = −29→31
3765 measured reflections

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F² > 2σ(F²)] = 0.026	Secondary atom site location: difference Fourier map
wR(F²) = 0.043	w = 1/[σ²(F_o²) + (0.0097P)² + 13.5872P] where P = (F_o² + 2F_c²)/3
S = 1.16	(Δ/σ)_max < 0.001
742 reflections	Δρ_max = 0.65 e Å⁻³
57 parameters	Δρ_min = −0.73 e Å⁻³

Crystal data top

RbSn₂(PO₄)₃	Z = 6
M_r = 607.76	Mo Kα radiation
Trigonal, R3	µ = 10.76 mm⁻¹
a = 8.340 (4) Å	T = 293 K
c = 24.007 (8) Å	0.20 × 0.05 × 0.05 mm
V = 1446.1 (6) Å³

Data collection top

Rigaku Mercury70 CCD diffractometer	742 independent reflections
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	711 reflections with I > 2σ(I)
T_min = 0.222, T_max = 0.615	R_int = 0.036
3765 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.026	0 restraints
wR(F²) = 0.043	w = 1/[σ²(F_o²) + (0.0097P)² + 13.5872P] where P = (F_o² + 2F_c²)/3
S = 1.16	Δρ_max = 0.65 e Å⁻³
742 reflections	Δρ_min = −0.73 e Å⁻³
57 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	0.6667	0.3333	−0.01707 (2)	0.00467 (15)
Rb1	0.3333	0.6667	0.1667	0.0164 (3)
P1	0.3780 (2)	0.3319 (3)	0.08383 (7)	0.0058 (2)
O1	0.2172 (6)	0.1463 (5)	0.10332 (14)	0.0090 (9)
Sn2	0.0000	0.0000	0.15528 (2)	0.00490 (15)
Rb2	0.0000	0.0000	0.0000	0.0227 (4)
O2	0.4497 (6)	0.2928 (6)	0.03015 (16)	0.0119 (10)
O3	0.3083 (6)	0.4664 (6)	0.07059 (16)	0.0093 (9)
O4	0.5248 (6)	0.4207 (6)	0.12987 (14)	0.0103 (10)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Sn1	0.0051 (2)	0.0051 (2)	0.0039 (3)	0.00253 (11)	0.000	0.000
Rb1	0.0221 (5)	0.0221 (5)	0.0051 (5)	0.0111 (2)	0.000	0.000
P1	0.0046 (8)	0.0068 (6)	0.0050 (6)	0.0022 (7)	0.0000 (6)	0.0008 (5)
O1	0.008 (2)	0.008 (2)	0.0097 (17)	0.0028 (17)	0.0044 (15)	0.0025 (14)
Sn2	0.0055 (2)	0.0055 (2)	0.0037 (3)	0.00275 (11)	0.000	0.000
Rb2	0.0304 (6)	0.0304 (6)	0.0073 (6)	0.0152 (3)	0.000	0.000
O2	0.009 (2)	0.018 (2)	0.009 (2)	0.008 (2)	0.0020 (17)	−0.0029 (17)
O3	0.014 (2)	0.010 (2)	0.0064 (17)	0.0077 (19)	−0.0023 (16)	0.0001 (16)
O4	0.011 (2)	0.008 (2)	0.0100 (17)	0.003 (2)	−0.0050 (17)	−0.0005 (16)

Geometric parameters (Å, º) top

Sn1—O2ⁱ	2.015 (4)	P1—Rb2	3.595 (2)
Sn1—O2ⁱⁱ	2.015 (4)	O1—Sn2	2.029 (4)
Sn1—O2	2.015 (4)	O1—Rb2	2.952 (4)
Sn1—O3ⁱⁱⁱ	2.033 (4)	Sn2—O1^xii	2.029 (4)
Sn1—O3^iv	2.033 (4)	Sn2—O1^xiii	2.029 (4)
Sn1—O3^v	2.033 (4)	Sn2—O4^xiv	2.033 (4)
Sn1—Rb1^vi	3.5915 (13)	Sn2—O4^xv	2.033 (4)
Rb1—O3^vii	2.794 (4)	Sn2—O4^viii	2.033 (4)
Rb1—O3^viii	2.794 (4)	Sn2—Rb2	3.7278 (13)
Rb1—O3^ix	2.794 (4)	Rb2—O1^xvi	2.952 (4)
Rb1—O3	2.793 (4)	Rb2—O1^xii	2.952 (4)
Rb1—O3^x	2.794 (4)	Rb2—O1^xvii	2.952 (4)
Rb1—O3^xi	2.794 (4)	Rb2—O1^iv	2.952 (4)
Rb1—O4^vii	3.289 (5)	Rb2—O1^xiii	2.952 (4)
Rb1—O4^x	3.288 (5)	Rb2—O2^xvii	3.375 (5)
Rb1—O4^ix	3.288 (5)	Rb2—O2^xvi	3.375 (5)
Rb1—O4^viii	3.288 (5)	Rb2—O2^xii	3.375 (5)
Rb1—O4^xi	3.288 (5)	Rb2—O2^iv	3.375 (5)
Rb1—O4	3.288 (5)	Rb2—O2^xiii	3.375 (5)
P1—O2	1.523 (4)	Rb2—O2	3.376 (5)
P1—O1	1.529 (4)	O3—Sn1^v	2.034 (4)
P1—O3	1.533 (4)	O4—Sn2^xiv	2.033 (4)
P1—O4	1.537 (4)

O2ⁱ—Sn1—O2ⁱⁱ	91.47 (17)	Rb2—P1—Rb1	121.07 (4)
O2ⁱ—Sn1—O2	91.47 (17)	P1—O1—Sn2	149.8 (3)
O2ⁱⁱ—Sn1—O2	91.47 (17)	P1—O1—Rb2	101.98 (17)
O2ⁱ—Sn1—O3ⁱⁱⁱ	83.62 (17)	Sn2—O1—Rb2	95.11 (15)
O2ⁱⁱ—Sn1—O3ⁱⁱⁱ	102.00 (17)	O1—Sn2—O1^xii	86.16 (16)
O2—Sn1—O3ⁱⁱⁱ	165.74 (17)	O1—Sn2—O1^xiii	86.16 (16)
O2ⁱ—Sn1—O3^iv	102.00 (17)	O1^xii—Sn2—O1^xiii	86.16 (16)
O2ⁱⁱ—Sn1—O3^iv	165.74 (17)	O1—Sn2—O4^xiv	93.48 (16)
O2—Sn1—O3^iv	83.62 (17)	O1^xii—Sn2—O4^xiv	89.54 (16)
O3ⁱⁱⁱ—Sn1—O3^iv	84.32 (17)	O1^xiii—Sn2—O4^xiv	175.70 (16)
O2ⁱ—Sn1—O3^v	165.74 (17)	O1—Sn2—O4^xv	175.70 (16)
O2ⁱⁱ—Sn1—O3^v	83.62 (17)	O1^xii—Sn2—O4^xv	93.48 (16)
O2—Sn1—O3^v	102.00 (17)	O1^xiii—Sn2—O4^xv	89.54 (16)
O3ⁱⁱⁱ—Sn1—O3^v	84.32 (17)	O4^xiv—Sn2—O4^xv	90.80 (16)
O3^iv—Sn1—O3^v	84.32 (17)	O1—Sn2—O4^viii	89.54 (16)
O2ⁱ—Sn1—Rb1^vi	124.22 (12)	O1^xii—Sn2—O4^viii	175.70 (16)
O2ⁱⁱ—Sn1—Rb1^vi	124.22 (12)	O1^xiii—Sn2—O4^viii	93.48 (16)
O2—Sn1—Rb1^vi	124.22 (12)	O4^xiv—Sn2—O4^viii	90.80 (16)
O3ⁱⁱⁱ—Sn1—Rb1^vi	50.81 (11)	O4^xv—Sn2—O4^viii	90.80 (16)
O3^iv—Sn1—Rb1^vi	50.81 (11)	O1—Sn2—Rb2	52.06 (11)
O3^v—Sn1—Rb1^vi	50.81 (11)	O1^xii—Sn2—Rb2	52.06 (11)
O3^vii—Rb1—O3^viii	58.49 (13)	O1^xiii—Sn2—Rb2	52.06 (11)
O3^vii—Rb1—O3^ix	58.49 (13)	O4^xiv—Sn2—Rb2	124.70 (11)
O3^viii—Rb1—O3^ix	58.49 (13)	O4^xv—Sn2—Rb2	124.69 (11)
O3^vii—Rb1—O3	180.0	O4^viii—Sn2—Rb2	124.69 (11)
O3^viii—Rb1—O3	121.51 (13)	O1^xvi—Rb2—O1^xii	180.0 (3)
O3^ix—Rb1—O3	121.51 (13)	O1^xvi—Rb2—O1^xvii	56.00 (13)
O3^vii—Rb1—O3^x	121.51 (13)	O1^xii—Rb2—O1^xvii	124.00 (13)
O3^viii—Rb1—O3^x	121.51 (13)	O1^xvi—Rb2—O1^iv	56.00 (13)
O3^ix—Rb1—O3^x	180.0	O1^xii—Rb2—O1^iv	124.00 (13)
O3—Rb1—O3^x	58.49 (13)	O1^xvii—Rb2—O1^iv	56.00 (13)
O3^vii—Rb1—O3^xi	121.51 (13)	O1^xvi—Rb2—O1^xiii	124.00 (13)
O3^viii—Rb1—O3^xi	180.0	O1^xii—Rb2—O1^xiii	56.00 (13)
O3^ix—Rb1—O3^xi	121.51 (13)	O1^xvii—Rb2—O1^xiii	124.00 (13)
O3—Rb1—O3^xi	58.49 (13)	O1^iv—Rb2—O1^xiii	180.00 (17)
O3^x—Rb1—O3^xi	58.49 (13)	O1^xvi—Rb2—O1	124.00 (13)
O3^vii—Rb1—O4^vii	47.14 (10)	O1^xii—Rb2—O1	56.00 (13)
O3^viii—Rb1—O4^vii	75.80 (10)	O1^xvii—Rb2—O1	180.0
O3^ix—Rb1—O4^vii	105.07 (10)	O1^iv—Rb2—O1	124.00 (13)
O3—Rb1—O4^vii	132.87 (10)	O1^xiii—Rb2—O1	56.00 (13)
O3^x—Rb1—O4^vii	74.93 (10)	O1^xvi—Rb2—O2^xvii	94.20 (11)
O3^xi—Rb1—O4^vii	104.20 (10)	O1^xii—Rb2—O2^xvii	85.80 (11)
O3^vii—Rb1—O4^x	104.20 (11)	O1^xvii—Rb2—O2^xvii	44.81 (10)
O3^viii—Rb1—O4^x	74.93 (10)	O1^iv—Rb2—O2^xvii	95.50 (10)
O3^ix—Rb1—O4^x	132.86 (10)	O1^xiii—Rb2—O2^xvii	84.50 (10)
O3—Rb1—O4^x	75.80 (11)	O1—Rb2—O2^xvii	135.19 (10)
O3^x—Rb1—O4^x	47.14 (10)	O1^xvi—Rb2—O2^xvi	44.81 (10)
O3^xi—Rb1—O4^x	105.07 (10)	O1^xii—Rb2—O2^xvi	135.19 (10)
O4^vii—Rb1—O4^x	66.94 (5)	O1^xvii—Rb2—O2^xvi	95.50 (10)
O3^vii—Rb1—O4^ix	75.80 (11)	O1^iv—Rb2—O2^xvi	94.20 (11)
O3^viii—Rb1—O4^ix	105.07 (10)	O1^xiii—Rb2—O2^xvi	85.80 (11)
O3^ix—Rb1—O4^ix	47.14 (10)	O1—Rb2—O2^xvi	84.50 (10)
O3—Rb1—O4^ix	104.20 (11)	O2^xvii—Rb2—O2^xvi	115.54 (5)
O3^x—Rb1—O4^ix	132.87 (10)	O1^xvi—Rb2—O2^xii	135.19 (10)
O3^xi—Rb1—O4^ix	74.93 (10)	O1^xii—Rb2—O2^xii	44.81 (10)
O4^vii—Rb1—O4^ix	113.06 (5)	O1^xvii—Rb2—O2^xii	84.50 (10)
O4^x—Rb1—O4^ix	180.0	O1^iv—Rb2—O2^xii	85.80 (11)
O3^vii—Rb1—O4^viii	105.07 (10)	O1^xiii—Rb2—O2^xii	94.20 (11)
O3^viii—Rb1—O4^viii	47.14 (10)	O1—Rb2—O2^xii	95.50 (10)
O3^ix—Rb1—O4^viii	75.80 (11)	O2^xvii—Rb2—O2^xii	64.46 (5)
O3—Rb1—O4^viii	74.93 (10)	O2^xvi—Rb2—O2^xii	180.00 (19)
O3^x—Rb1—O4^viii	104.20 (11)	O1^xvi—Rb2—O2^iv	95.50 (10)
O3^xi—Rb1—O4^viii	132.87 (10)	O1^xii—Rb2—O2^iv	84.50 (10)
O4^vii—Rb1—O4^viii	113.06 (5)	O1^xvii—Rb2—O2^iv	94.20 (11)
O4^x—Rb1—O4^viii	66.94 (5)	O1^iv—Rb2—O2^iv	44.81 (10)
O4^ix—Rb1—O4^viii	113.06 (5)	O1^xiii—Rb2—O2^iv	135.19 (10)
O3^vii—Rb1—O4^xi	74.93 (10)	O1—Rb2—O2^iv	85.80 (11)
O3^viii—Rb1—O4^xi	132.86 (10)	O2^xvii—Rb2—O2^iv	115.54 (5)
O3^ix—Rb1—O4^xi	104.20 (11)	O2^xvi—Rb2—O2^iv	115.54 (5)
O3—Rb1—O4^xi	105.08 (10)	O2^xii—Rb2—O2^iv	64.46 (5)
O3^x—Rb1—O4^xi	75.80 (11)	O1^xvi—Rb2—O2^xiii	84.50 (10)
O3^xi—Rb1—O4^xi	47.14 (10)	O1^xii—Rb2—O2^xiii	95.50 (10)
O4^vii—Rb1—O4^xi	66.94 (5)	O1^xvii—Rb2—O2^xiii	85.80 (11)
O4^x—Rb1—O4^xi	113.06 (5)	O1^iv—Rb2—O2^xiii	135.19 (10)
O4^ix—Rb1—O4^xi	66.94 (5)	O1^xiii—Rb2—O2^xiii	44.81 (10)
O4^viii—Rb1—O4^xi	180.0	O1—Rb2—O2^xiii	94.20 (11)
O3^vii—Rb1—O4	132.86 (10)	O2^xvii—Rb2—O2^xiii	64.46 (5)
O3^viii—Rb1—O4	104.20 (10)	O2^xvi—Rb2—O2^xiii	64.46 (5)
O3^ix—Rb1—O4	74.92 (10)	O2^xii—Rb2—O2^xiii	115.54 (5)
O3—Rb1—O4	47.14 (10)	O2^iv—Rb2—O2^xiii	180.0 (2)
O3^x—Rb1—O4	105.08 (10)	O1^xvi—Rb2—O2	85.80 (11)
O3^xi—Rb1—O4	75.80 (10)	O1^xii—Rb2—O2	94.20 (11)
O4^vii—Rb1—O4	180.0	O1^xvii—Rb2—O2	135.19 (10)
O4^x—Rb1—O4	113.06 (5)	O1^iv—Rb2—O2	84.50 (10)
O4^ix—Rb1—O4	66.94 (5)	O1^xiii—Rb2—O2	95.50 (10)
O4^viii—Rb1—O4	66.94 (5)	O1—Rb2—O2	44.81 (10)
O4^xi—Rb1—O4	113.06 (5)	O2^xvii—Rb2—O2	180.0
O2—P1—O1	106.4 (3)	O2^xvi—Rb2—O2	64.47 (5)
O2—P1—O3	108.3 (2)	O2^xii—Rb2—O2	115.53 (5)
O1—P1—O3	110.1 (3)	O2^iv—Rb2—O2	64.46 (5)
O2—P1—O4	114.1 (2)	O2^xiii—Rb2—O2	115.54 (5)
O1—P1—O4	110.6 (2)	P1—O2—Sn1	148.8 (3)
O3—P1—O4	107.4 (2)	P1—O2—Rb2	85.6 (2)
O2—P1—Rb2	69.43 (19)	Sn1—O2—Rb2	125.48 (17)
O1—P1—Rb2	53.44 (15)	P1—O3—Sn1^v	144.2 (3)
O3—P1—Rb2	86.57 (16)	P1—O3—Rb1	108.91 (19)
O4—P1—Rb2	162.60 (19)	Sn1^v—O3—Rb1	94.85 (15)
O2—P1—Rb1	147.0 (2)	P1—O4—Sn2^xiv	134.6 (3)
O1—P1—Rb1	103.79 (16)	P1—O4—Rb1	88.59 (19)
O3—P1—Rb1	47.30 (15)	Sn2^xiv—O4—Rb1	128.46 (15)
O4—P1—Rb1	66.10 (17)

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

Experimental details

Crystal data
Chemical formula	RbSn₂(PO₄)₃
M_r	607.76
Crystal system, space group	Trigonal, R3
Temperature (K)	293
a, c (Å)	8.340 (4), 24.007 (8)
V (Å³)	1446.1 (6)
Z	6
Radiation type	Mo Kα
µ (mm⁻¹)	10.76
Crystal size (mm)	0.20 × 0.05 × 0.05

Data collection
Diffractometer	Rigaku Mercury70 CCD diffractometer
Absorption correction	Multi-scan (ABSCOR; Higashi, 1995)
T_min, T_max	0.222, 0.615
No. of measured, independent and observed [I > 2σ(I)] reflections	3765, 742, 711
R_int	0.036
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.026, 0.043, 1.16
No. of reflections	742
No. of parameters	57
	w = 1/[σ²(F_o²) + (0.0097P)² + 13.5872P] where P = (F_o² + 2F_c²)/3
Δρ_max, Δρ_min (e Å⁻³)	0.65, −0.73

Computer programs: CrystalClear (Rigaku, 2004), SHELXS97 (Sheldrick, 2008) and PLATON (Spek, 2009), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2004), SHELXTL (Sheldrick, 2008).

Selected bond lengths (Å) top

Sn1—O2	2.015 (4)	P1—O1	1.529 (4)
Sn1—O3ⁱ	2.033 (4)	P1—O3	1.533 (4)
P1—O2	1.523 (4)	P1—O4	1.537 (4)

Symmetry code: (i) y, −x+y, −z.

Acknowledgements

The authors acknowledge the Doctoral Foundation of Henan Polytechnic University (grant No. B2010–92, 648483).

References

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