The quinter­nary thio­phosphate Cs0.5Ag0.5Nb2PS10

Sojeong Park; Hoseop Yun

doi:10.1107/S1600536810021768

. 2010 Jun 16;66(Pt 7):i51–i52. doi: 10.1107/S1600536810021768

The quinternary thiophosphate Cs_0.5Ag_0.5Nb₂PS₁₀

Sojeong Park ^a, Hoseop Yun ^a,^*

PMCID: PMC3006697 PMID: 21587667

Abstract

The quinternary thiophosphate Cs_0.5Ag_0.5Nb₂PS₁₀, cesium silver tris(disulfido)[tetrathiophosphato(V)]diniobate(IV), has been prepared from the elements using a CsCl flux. The crystal structure is made up of _∞ ¹[Nb₂PS₁₀] chains expanding along [010]. These chains are built up from bicapped trigonal-prismatic [Nb₂S₁₂] units and tetrahedral [PS₄] groups and are linked through a linear S—Ag—S bridge, forming a two-dimensional layer. These layers then stack on top of each other, completing the three-dimensional structure with an undulating van der Waals gap. The disordered Cs⁺ ions reside on sites with half-occupation in the voids of this arrangement. Short [2.8843 (5) Å] and long [3.7316 (4) Å] Nb—Nb distances alternate along the chains, and anionic S₂ ²⁻ and S²⁻ species are observed. The charge balance of the compound can be represented by the formula [Cs⁺]_0.5[Ag⁺]_0.5[Nb⁴⁺]₂[PS₄ ³⁻][S₂ ²⁻]₃.

Related literature

For Nb₂PS₁₀-related quaternary thiophosphates, see: Do & Yun (1996 ▶) for KNb₂PS₁₀, Kim & Yun (2002 ▶) for RbNb₂PS₁₀, Kwak et al. (2007 ▶) for CsNb₂PS₁₀, Bang et al. (2008 ▶) for TlNb₂PS₁₀, and Do & Yun (2009 ▶) for Ag_0.88Nb₂PS₁₀. For quintenary thiophosphates, 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. PLATON (Spek, 2009 ▶) was used for structure validation. For typical Nb—P and P—S bond length, see: Brec et al. (1983 ▶), and for typical Nb⁴⁺–Nb⁴⁺ bond lengths, see: Angenault et al. (2000 ▶). For general background, see: Lee et al. (1988 ▶).

Experimental

Crystal data

Cs_0.5Ag_0.5Nb₂PS₁₀
M _r = 657.78
Monoclinic,
a = 7.3594 (3) Å
b = 12.8534 (4) Å
c = 13.7788 (6) Å
β = 91.0886 (12)°
V = 1303.15 (8) Å³
Z = 4
Mo Kα radiation
μ = 5.54 mm⁻¹
T = 290 K
0.30 × 0.06 × 0.04 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T _min = 0.602, T _max = 1.000
12389 measured reflections
2991 independent reflections
2430 reflections with I > 2σ(I)
R _int = 0.049

Refinement

R[F ² > 2σ(F ²)] = 0.034
wR(F ²) = 0.075
S = 1.08
2991 reflections
133 parameters
Δρ_max = 1.18 e Å⁻³
Δρ_min = −1.27 e Å⁻³

Data collection: RAPID-AUTO (Rigaku, 2006 ▶); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO; 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 Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810021768/wm2357sup1.cif

e-66-00i51-sup1.cif^{(18.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810021768/wm2357Isup2.hkl

e-66-00i51-Isup2.hkl^{(143.9KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected geometric parameters (Å, °).

Ag—S1	2.4625 (13)
Nb1—S4ⁱ	2.4953 (13)
Nb1—S7ⁱ	2.4958 (12)
Nb1—S8ⁱ	2.5055 (13)
Nb1—S10ⁱ	2.5231 (13)
Nb1—S9	2.5658 (12)
Nb1—S2	2.5895 (12)
Nb1—S5	2.5993 (13)
Nb1—S6	2.6103 (12)
Nb2—S10	2.4910 (13)
Nb2—S7	2.4932 (13)
Nb2—S4	2.4985 (12)
Nb2—S8	2.5075 (12)
Nb2—S5	2.5643 (13)
Nb2—S9	2.5670 (12)
Nb2—S3	2.5920 (12)
Nb2—S6	2.6250 (12)
P—S1	1.9962 (18)
P—S3	2.0391 (17)
P—S2	2.0527 (17)
P—S6	2.0851 (17)

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S1—Ag—S1ⁱⁱ

180

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

This work was supported by the Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF-2009–0094047). Use was made of the X-ray facilities supported by Ajou University.

supplementary crystallographic information

Comment

During an effort to expand representatives of group 5 transition metal thiophosphates by substituting various monovalent cations, we were able to prepare a new derivative in this system. Here we report the synthesis and characterization of the new layered quinternary thiophosphate, Cs_0.5Ag_0.5Nb₂PS₁₀.

The title compound is isostructural with the previously reported K_0.34Cu_0.5Nb₂PS₁₀ (Kwak & Yun, 2008). The _∞¹[Nb₂PS₁₀] chains found in this structure are composed of the typical biprismatic [Nb₂S₁₂] and tetrahedral [PS₄] units. The Nb atoms are surrounded by 8 S atoms in a bicapped trigonal-prismatic fashion. Two prisms are sharing a rectangular face to form the [Nb₂S₁₂] unit. These units are bound through the S—S prism edges and through one of the capping sulfur atoms to make _∞¹[Nb₂S₉] chains. One of the S atoms at the prism edge and two other capping S atoms are bound to the P atom to which an additional S atom (S1) is attached to complete the _∞¹[Nb₂PS₁₀] chains. These anionic chains propagate parallel to [010] and are linked through the linear S—Ag—S bridge to form a two-dimensional layer along (201). These layers then stack on top of each other to complete the three-dimensional structure with an undulating van der Waals gap. The disordered Cs⁺ cations reside in the voids of this arrangement.

The Nb—S and P—S distances are in agreement with those found in other related phases (Brec et al., 1983). Along the chain, The Nb(1)···Nb(2) interactions alternate in the sequence of one short (2.8843 (5) Å) and one long (3.7316 (4) Å) distance. The short distance is close to that of the typical Nb⁴⁺—Nb⁴⁺ bond (Angenault et al., 2000), and the long Nb···Nb distance shows that there is no significant intermetallic bonding interaction. Such an arrangement is consistent with the high electric resistivity of the crystal along the needle axis (b axis).

The coordination around the Ag atom (1 symmetry) can be described as a [2 + 4] interaction. Four S atoms are bound to the Ag atoms in the plane (Ag—S6, 3.139 (3) Å, Ag—S9, 3.232 (3) Å), whereas two trans S atoms are coordinated to the Ag atom at short distances of Ag—S1 = 2.4625 (13) Å. The large ADPs of Ag could be explained by the second-order Jahn-Teller coupling between the filled Ag e_g and the empty s orbitals (Lee et al., 1988), which is a common trend of d¹⁰ elements. The charge balance of the compound can be represented by the formula [Cs⁺]_0.5[Ag⁺]_0.5[Nb⁴⁺]₂[PS₄^3-][S₂^2-]₃.

For Nb₂PS₁₀-related quaternary thiophosphates, see: Do & Yun (1996) for KNb₂PS₁₀, Kim & Yun (2002) for RbNb₂PS₁₀, Kwak et al. (2007) for CsNb₂PS₁₀, Bang et al. (2008) for TlNb₂PS₁₀, and Do & Yun (2009) for Ag_0.88Nb₂PS₁₀; for quinternary thiophosphates, 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.

Experimental

Cs_0.5Ag_0.5Nb₂PS₁₀ was prepared by the reaction of elemental powders, using the reactive halide-flux technique. Ag powder (CERAC 99.999%), Nb powder (CERAC 99.8%), P powder (CERAC 99.5%) and S powder (Aldrich 99.999%) were mixed in a fused silica tube in a molar ratio of Ag:Nb:P:S=1:2:1:10 and then CsCl was added in a weight ratio of AgNb₂PS₁₀:CsCl=1:3. The tube was evacuated to 0.133 Pa, sealed and heated gradually (50 K/h) to 973 K, where it was kept for 72 h. The tube was cooled to room temperature at the rate of 4 K/h. The excess halide was removed with distilled water and dark red needle-shaped crystals were obtained. The crystals are stable in air and water. A qualitative X-ray fluorescence analysis of the needles indicated the presence of Cs, Ag, Nb, P, and S. The composition of the compound was determined by single-crystal X-ray diffraction.