(IUCr) Redetermination of AgNb2PS10 revealing a silver deficiency

Volume 65
Part 8
Pages i56-i57
August 2009

Received 11 June 2009
Accepted 29 June 2009
Online 4 July 2009

Key indicators
Single-crystal X-ray study
T = 290 K
Mean (S-P) = 0.004 Å
Disorder in main residue
R = 0.045
wR = 0.109
Data-to-parameter ratio = 16.5
Details

Redetermination of AgNb₂PS₁₀ revealing a silver deficiency

Junghwan Do ^a and Hoseop Yun ^b ^*

^aDepartment of Chemistry, Konkuk University, Seoul 143-701, Republic of Korea, and ^bDivision of Energy Systems Research and Department of Chemistry, Ajou University, Suwon 443-749, Republic of Korea
Correspondence e-mail: hsyun@ajou.ac.kr

In comparison with a previous crystallographic study [Goh et al. (2002). J. Solid State Chem. 168, 119-125] of the title compound, silver diniobium tris(disulfide) tetrathiophosphate(V), that reports a full occupation of the silver position and isotropic displacement parameters for the atoms, the current redetermination reveals a silver deficiency with a site-occupation factor of 0.88 (1) and reports all atoms with anisotropic displacement parameters. The structure of Ag_0.88Nb₂PS₁₀ is composed of ¹[Nb₂PS₁₀] chains, which are built up from pairs of distorted bicapped trigonal-prismatic [NbS₈] polyhedra forming [Nb₂S₁₂] dimers and of tetrahedral [PS₄] groups. These chains are connected via the statistically disordered Ag⁺ ions, forming double layers. Adjacent layers are stacked solely through van der Waals forces into a three-dimensional structure. Short and long Nb-Nb distances [2.880 (1) and 3.770 (2) Å, respectively] alternate along the chain and S₂^2- and S^2- anionic species are observed.

Related literature

The synthesis and structural characterization of stoichiometric AgNb₂PS₁₀ and NaNb₂PS₁₀ have been published (Goh et al., 2002). For Nb₂PS₁₀-related quaternary thiophosphates with general formula MNb₂PS₁₀, see: Do & Yun (1996) for KNb₂PS₁₀, Kim & Yun (2002) for RbNb₂PS₁₀, Kwak et al. (2007) for CsNb₂PS₁₀, and Bang et al. (2008) for TlNb₂PS₁₀; for related pentanary thiophosphates M,M'Nb₂PS₁₀, see: Kwak & Yun (2008) for K_0.34Cu_0.5Nb₂PS₁₀, Dong et al. (2005a) for K_0.5Ag_0.5Nb₂PS₁₀, and Dong et al. (2005b) for Rb_0.38Ag_0.5Nb₂PS₁₀. For data standardization, see: Gelato & Parthé (1987). For ionic radii, see: Shannon (1976). For structure validation, see: Spek (2009). For typical P-S bond distances, see: Brec et al. (1983). For typical Nb⁴⁺-Nb⁴⁺ bond distances, see: Angenault et al. (2000).

Experimental

Crystal data

Ag_0.88Nb₂PS₁₀
M_r = 631.78
Monoclinic, C 2/c
a = 24.001 (5) Å
b = 7.7711 (17) Å
c = 12.960 (3) Å
= 94.833 (19)°
V = 2408.6 (9) Å³
Z = 8
Mo K radiation
= 5.1 mm^-1
T = 290 K
0.60 × 0.06 × 0.04 mm

Data collection

MAC Science MXC3 diffractometer
Absorption correction: analytical (de Meulenaer & Tompa, 1965) T_min = 0.727, T_max = 0.821
2221 measured reflections
2114 independent reflections
1835 reflections with I > 2(I)
R_int = 0.017
2 standard reflections every 100 reflections intensity decay: none

Refinement

R[F² > 2(F²)] = 0.045
wR(F²) = 0.109
S = 1.16
2114 reflections
128 parameters
_max = 1.82 e Å^-3
_min = -1.20 e Å^-3

Table 1
Selected geometric parameters (Å, °)

Ag-S1ⁱ	2.536 (3)
Ag-S9ⁱⁱ	2.620 (3)
Ag-S2ⁱⁱⁱ	2.875 (3)
Ag-S8^iv	2.916 (3)
Ag-S1ⁱⁱⁱ	2.965 (4)
Ag-S3	3.091 (3)
Nb1-S5	2.462 (2)
Nb1-S2^v	2.466 (2)
Nb1-S7^vi	2.518 (3)
Nb1-S6^iv	2.551 (2)
Nb1-S3	2.554 (3)
Nb1-S4^v	2.562 (2)
Nb1-S8^iv	2.573 (3)
Nb1-S10^iv	2.659 (2)
Nb2-S3ⁱⁱ	2.476 (3)
Nb2-S7	2.479 (3)
Nb2-S5ⁱⁱ	2.508 (2)
Nb2-S2^vii	2.551 (3)
Nb2-S4ⁱⁱ	2.558 (2)
Nb2-S6	2.569 (3)
Nb2-S9	2.630 (3)
Nb2-S10	2.656 (2)
P-S1^vi	2.009 (4)
P-S8	2.048 (4)
P-S9	2.059 (4)
P-S10	2.065 (3)

S1^vi-P-S8	108.46 (17)
S1^vi-P-S9	112.81 (17)
S8-P-S9	111.87 (16)
S1^vi-P-S10	117.65 (16)
S8-P-S10	104.24 (14)
S9-P-S10	101.46 (14)
Symmetry codes: (i) $[-x, y, -z+{\script{1\over 2}}]$ ; (ii) $[-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iii) $[x, -y+1, z-{\script{1\over 2}}]$ ; (iv) $[-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z]$ ; (v) $[x, -y, z-{\script{1\over 2}}]$ ; (vi) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (vii) $[-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]$ .

Data collection: MAC Science MXC3 (MAC Science, 1994 $[MAC Science (1994). MXC Diffractometer Control Software. Mac Science Corporation, Tokyo, Japan.]$ ); cell refinement: MAC Science MXC3; data reduction: MAC Science MXC3; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: locally modified version of ORTEP (Johnson, 1965); software used to prepare material for publication: WinGX (Farrugia, 1999).

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WM2240 ).

Acknowledgements

This work was supported by a Korea Research Foundation Grant funded by the Korean Government (MOEHRD) (KRF-2007-412-J04001). Use was made of the X-ray facilities supported by Ajou University.

References

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