inorganic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

The two-dimensional thio­phosphate CsCrP2S7

aDivision of Energy Systems Research and Department of Chemistry, Ajou University, Suwon 443-749, Republic of Korea
*Correspondence e-mail: hsyun@ajou.ac.kr

(Received 24 July 2010; accepted 1 August 2010; online 11 August 2010)

The quaternary title compound, caesium chromium(III) hepta­thio­diphosphate(V), CsCrP2S7, has been synthesized using the reactive halide flux method. It is isotypic with other AMP2S7 (A = alkali metal; M = Cr, V or In) structures and consists of two-dimensional 2[CrP2S7] layers extending parallel to (001) which are separated from each other by Cs+ ions (symmetry 2). The layer is built up from slightly distorted octa­hedral [CrS6] units (symmetry 2) and bent [P2S7] units consisting of two corner-sharing [PS4] tetra­hedra. The [CrS6] octa­hedra share two edges and two corners with the [PS4] tetra­hedra. There are only van der Waals inter­actions present between the layers. The Cs+ ions are located in this van der Waals gap and stabilize the structure through weak ionic inter­actions. The classical charge balance of the title compound can be expressed as [Cs+][Cr3+][P5+]2[S2−]7.

Related literature

For AMP2S7-related quaternary thio­phosphates, see: Kopnin et al. (2000[Kopnin, E., Coste, S., Jobic, S., Evain, M. & Brec, R. (2000). Mater. Res. Bull. 35, 1401-1410.]) for KMP2S7 (M = Cr, V, In); Durand et al. (1993[Durand, E., Evain, M. & Brec, R. (1993). J. Solid State Chem. 102, 146-155.]) for RbVP2S7; Gutzmann et al. (2005[Gutzmann, A., Näther, C. & Bensch, W. (2005). Acta Cryst. E61, i6-i8.]) for CsVP2S7. For the related mixed-metallic phase KV1-xCrxP2S7, see: Sekizawa et al. (2004[Sekizawa, K., Sashida, M., Takano, Y., Takahashi, Y. & Takase, K. (2004). J. Magn. Magn. Mater. 272-276, e597-e598.]). Related structures were reported by Coste et al. (2001[Coste, S., Kopnin, E., Evain, M., Jobic, S., Payen, C. & Brec, R. (2001). J. Solid State Chem. 162, 195-203.]); Derstroff et al. (2002[Derstroff, V., Ensling, J., Ksenofontov, V., Gütlich, P. & Tremel, W. (2002). Z. Anorg. Allg. Chem. 628, 1346-1354.]); Toffoli et al. (1982[Toffoli, P., Khodadad, P. & Rodier, N. (1982). Acta Cryst. B38, 2374-2378.]); Wang et al. (1989[Wang, Y. P., Lii, K. H. & Wang, S. L. (1989). Acta Cryst. C45, 1417-1418.]).

Experimental

Crystal data
  • CrCsP2S7

  • Mr = 471.34

  • Monoclinic, C 2

  • a = 8.5867 (7) Å

  • b = 9.5461 (7) Å

  • c = 6.7504 (6) Å

  • β = 97.572 (3)°

  • V = 548.50 (8) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 5.87 mm−1

  • T = 290 K

  • 0.14 × 0.02 × 0.02 mm

Data collection
  • Rigaku R-AXIS RAPID diffractometer

  • Absorption correction: multi-scan (ABSCOR; Higashi, 1995[Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.608, Tmax = 1.000

  • 2714 measured reflections

  • 1268 independent reflections

  • 1052 reflections with I > 2σ(I)

  • Rint = 0.039

Refinement
  • R[F2 > 2σ(F2)] = 0.029

  • wR(F2) = 0.073

  • S = 1.18

  • 1268 reflections

  • 52 parameters

  • 1 restraint

  • Δρmax = 1.01 e Å−3

  • Δρmin = −1.09 e Å−3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), 593 Friedel pairs

  • Flack parameter: −0.01 (3)

Table 1
Selected geometric parameters (Å, °)

Cr—S1 2.414 (2)
Cr—S2 2.440 (2)
Cr—S3i 2.430 (2)
P—S1 2.025 (3)
P—S2 2.024 (3)
P—S3 2.012 (2)
P—S4 2.134 (2)
Pii—S4—P 107.50 (14)
Symmetry codes: (i) [x-{\script{1\over 2}}, y-{\script{1\over 2}}, z]; (ii) -x+1, y, -z+1.

Data collection: RAPID-AUTO (Rigaku, 2006[Rigaku (2006). RAPID-AUTO Manual, Rigaku Corporation, Tokyo, Japan.]); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: locally modified version of ORTEP (Johnson, 1965[Johnson, C. K. (1965). ORTEP. Report ORNL-3794. Oak Ridge National Laboratory, Tennessee, USA.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

During an attempt to prepare new chromium thiophosphates with the use of halide fluxes, a new compound was isolated. Here we report the synthesis and structure of the new layered quaternary thiophosphate, CsCrP2S7.

The title compound is a new member of the previously reported isotypic AMP2S7 family (A = alkali metal; M = Cr, V, or In) (Kopnin et al., 2000; Durand et al., 1993; Gutzmann et al., 2005, Sekizawa et al. , 2004). The structure of CsCrP2S7 consists of layers with composition 2[CrP2S7]- which are composed of [CrS6] octahedra and bent [P2S74-] units made up of two corner-sharing [PS4] tetrahedra. As usually found in other chromium sulfides (Derstroff et al., 2002), each Cr atom is surrounded by six S atoms in a (slightly distorted) octahedral arrangement. In the title compound they share two edges and two corners with the [PS4] tetrahedra to form the two-dimensional infinite layer extending parallel to (001) (Fig. 1). There are only van der Waals interactions between the layers and the Cs+ ions in this van der Waals gap stabilize the structure through weak ionic interactions (Fig. 2).

While both the [CrS6] octahedron and the [PS4] tetrahedron show angular distortions, the Cr—S and P—S distances are rather regular and in good agreement with those found in other related phases (e.g. Coste et al., 2001). Atom S4 is bridging two P atoms in the [P2S74-] units. The bridging P—S4 bond is longer than those of the terminal bonds, a characteristic feature for two condensed PS4 tetrahedra (Toffoli et al., 1982) or PO4 tetrahedra (Wang et al., 1989).

The Cs+ ion is surrounded by twelve S atoms if an arbitrarily choosen cut-off of 4.2 Å for the Cs—S bonding interactions is used. The anharmonic behavior of the alkali metal ion, as observed in the isotypic K or Rb analogues (Kopnin et al., 2000; Durand et al., 1993), is not found here. The harmonic behavior of the Cs+ ion in the title compound could be due to the larger ionic radius and hence to a larger coordination number (Gutzmann et al., 2005). The classical charge balance of the title compound can be expressed as [Cs+][Cr3+][[P5+]2[S2-]7.

Related literature top

For AMP2S7-related quaternary thiophosphates, see: Kopnin et al. (2000) for KMP2S7 (M = Cr, V, In); Durand et al. (1993) for RbVP2S7; Gutzmann et al. (2005) for CsVP2S7. For the related mixed-metallic phase KV1-xCrxP2S7, see: Sekizawa et al. (2004). Related structures were reported by Coste et al. (2001); Derstroff et al. (2002); Toffoli et al. (1982); Wang et al. (1989).

Experimental top

The title compound, CsCrP2S7, was prepared by the reaction of the elemental Cr, P and S with the use of the reactive alkali metal halide flux technique. A combination of the pure elements, Cr powder (CERAC 99.95%), P powder (CERAC 99.5%) and S powder (Aldrich 99.999%) were mixed in a fused silica tube in a molar ratio of Cr: P: S = 1: 2: 6 with CsCl/LiCl. The mass ratio of the reactants and the alkali halide flux was 1: 3. The tube was evacuated to 0.133 Pa, sealed and heated gradually (50 K/h) to 923 K, where it was kept for 72 h. The tube was cooled to 473 K at 3 K/h and then was quenched to room temperature. The excess halides were removed with distilled water and dark brown needle shaped crystals were obtained. The crystals are stable in air and water. Semi-qualitative analysis of the crystals with XRF indicated the presence of Cs, Cr, P, and S. No other element was detected.

Refinement top

A difference Fourier synthesis calculated with phase based on the final parameters shows that the highest residual electron density (1.01 e/Å3) is 0.89 Å from the Cs site and the deepest hole (-1.09 e/Å3) is 1.74 Å from the S3 site.

Structure description top

During an attempt to prepare new chromium thiophosphates with the use of halide fluxes, a new compound was isolated. Here we report the synthesis and structure of the new layered quaternary thiophosphate, CsCrP2S7.

The title compound is a new member of the previously reported isotypic AMP2S7 family (A = alkali metal; M = Cr, V, or In) (Kopnin et al., 2000; Durand et al., 1993; Gutzmann et al., 2005, Sekizawa et al. , 2004). The structure of CsCrP2S7 consists of layers with composition 2[CrP2S7]- which are composed of [CrS6] octahedra and bent [P2S74-] units made up of two corner-sharing [PS4] tetrahedra. As usually found in other chromium sulfides (Derstroff et al., 2002), each Cr atom is surrounded by six S atoms in a (slightly distorted) octahedral arrangement. In the title compound they share two edges and two corners with the [PS4] tetrahedra to form the two-dimensional infinite layer extending parallel to (001) (Fig. 1). There are only van der Waals interactions between the layers and the Cs+ ions in this van der Waals gap stabilize the structure through weak ionic interactions (Fig. 2).

While both the [CrS6] octahedron and the [PS4] tetrahedron show angular distortions, the Cr—S and P—S distances are rather regular and in good agreement with those found in other related phases (e.g. Coste et al., 2001). Atom S4 is bridging two P atoms in the [P2S74-] units. The bridging P—S4 bond is longer than those of the terminal bonds, a characteristic feature for two condensed PS4 tetrahedra (Toffoli et al., 1982) or PO4 tetrahedra (Wang et al., 1989).

The Cs+ ion is surrounded by twelve S atoms if an arbitrarily choosen cut-off of 4.2 Å for the Cs—S bonding interactions is used. The anharmonic behavior of the alkali metal ion, as observed in the isotypic K or Rb analogues (Kopnin et al., 2000; Durand et al., 1993), is not found here. The harmonic behavior of the Cs+ ion in the title compound could be due to the larger ionic radius and hence to a larger coordination number (Gutzmann et al., 2005). The classical charge balance of the title compound can be expressed as [Cs+][Cr3+][[P5+]2[S2-]7.

For AMP2S7-related quaternary thiophosphates, see: Kopnin et al. (2000) for KMP2S7 (M = Cr, V, In); Durand et al. (1993) for RbVP2S7; Gutzmann et al. (2005) for CsVP2S7. For the related mixed-metallic phase KV1-xCrxP2S7, see: Sekizawa et al. (2004). Related structures were reported by Coste et al. (2001); Derstroff et al. (2002); Toffoli et al. (1982); Wang et al. (1989).

Computing details top

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

Figures top
[Figure 1] Fig. 1. The interconnection mode of the [CrS6] octahedron and the [P2S74-] units with the atom labelling scheme. Displacement ellipsoids are drawn at the 80% probability level.
[Figure 2] Fig. 2. A perspective view of CsCrP2S7 down the b axis showing the stacking of the layers. Filled, dark gray, pale gray, and open circles represent Cr, P, Cs, and S atoms, respectively. The Cs—S bonds are omitted for clarity. The displacement ellipsoids are drawn at the 80% probability level.
caesium chromium(III) heptathiodiphosphate(V) top
Crystal data top
CrCsP2S7F(000) = 442
Mr = 471.34Dx = 2.854 Mg m3
Monoclinic, C2Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C 2yCell parameters from 10764 reflections
a = 8.5867 (7) Åθ = 3.0–27.5°
b = 9.5461 (7) ŵ = 5.87 mm1
c = 6.7504 (6) ÅT = 290 K
β = 97.572 (3)°Needle, dark brown
V = 548.50 (8) Å30.14 × 0.02 × 0.02 mm
Z = 2
Data collection top
Rigaku R-AXIS RAPID
diffractometer
1052 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.039
ω scansθmax = 27.5°, θmin = 3.0°
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
h = 1011
Tmin = 0.608, Tmax = 1.000k = 1212
2714 measured reflectionsl = 88
1268 independent reflections
Refinement top
Refinement on F21 restraint
Least-squares matrix: full w = 1/[σ2(Fo2) + (0.0208P)2 + 0.2322P]
where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.029(Δ/σ)max < 0.001
wR(F2) = 0.073Δρmax = 1.01 e Å3
S = 1.18Δρmin = 1.09 e Å3
1268 reflectionsAbsolute structure: Flack (1983), 593 Friedel pairs
52 parametersAbsolute structure parameter: 0.01 (3)
Crystal data top
CrCsP2S7V = 548.50 (8) Å3
Mr = 471.34Z = 2
Monoclinic, C2Mo Kα radiation
a = 8.5867 (7) ŵ = 5.87 mm1
b = 9.5461 (7) ÅT = 290 K
c = 6.7504 (6) Å0.14 × 0.02 × 0.02 mm
β = 97.572 (3)°
Data collection top
Rigaku R-AXIS RAPID
diffractometer
1268 independent reflections
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
1052 reflections with I > 2σ(I)
Tmin = 0.608, Tmax = 1.000Rint = 0.039
2714 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0291 restraint
wR(F2) = 0.073Δρmax = 1.01 e Å3
S = 1.18Δρmin = 1.09 e Å3
1268 reflectionsAbsolute structure: Flack (1983), 593 Friedel pairs
52 parametersAbsolute structure parameter: 0.01 (3)
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cs0.50.39716 (9)00.0432 (2)
Cr00.48837 (14)0.50.0198 (4)
P0.3006 (2)0.63947 (16)0.4247 (3)0.0188 (4)
S10.15938 (19)0.51649 (17)0.2337 (3)0.0235 (4)
S20.1839 (2)0.65997 (17)0.6648 (3)0.0272 (5)
S30.3619 (2)0.81248 (18)0.2834 (3)0.0283 (5)
S40.50.5073 (3)0.50.0218 (5)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cs0.0254 (4)0.0753 (6)0.0289 (4)00.0042 (3)0
Cr0.0113 (8)0.0170 (7)0.0317 (10)00.0048 (7)0
P0.0110 (9)0.0179 (8)0.0274 (11)0.0028 (6)0.0022 (8)0.0004 (8)
S10.0149 (8)0.0271 (9)0.0291 (10)0.0051 (7)0.0053 (8)0.0056 (8)
S20.0235 (11)0.0249 (9)0.0355 (12)0.0039 (7)0.0127 (9)0.0090 (9)
S30.0258 (10)0.0247 (9)0.0319 (11)0.0102 (8)0.0056 (9)0.0070 (9)
S40.0119 (11)0.0249 (13)0.0288 (15)00.0039 (10)0
Geometric parameters (Å, º) top
Cr—S1i2.414 (2)P—S12.025 (3)
Cr—S12.414 (2)P—S22.024 (3)
Cr—S22.440 (2)P—S32.012 (2)
Cr—S2i2.440 (2)P—S42.134 (2)
Cr—S3ii2.430 (2)S3—Criv2.430 (2)
Cr—S3iii2.430 (2)S4—Pv2.134 (2)
S1i—Cr—S1167.23 (10)S3iii—Cr—S2i166.77 (6)
S1i—Cr—S3ii104.20 (7)S2—Cr—S2i95.64 (10)
S1—Cr—S3ii84.74 (7)S3—P—S2119.23 (11)
S1i—Cr—S3iii84.74 (7)S3—P—S1110.24 (12)
S1—Cr—S3iii104.20 (7)S2—P—S1104.37 (10)
S3ii—Cr—S3iii92.60 (9)S3—P—S4110.27 (11)
S1i—Cr—S288.98 (7)S2—P—S4109.45 (11)
S1—Cr—S282.44 (6)S1—P—S4101.73 (10)
S3ii—Cr—S2166.77 (6)P—S1—Cr86.60 (9)
S3iii—Cr—S287.38 (7)P—S2—Cr85.93 (9)
S1i—Cr—S2i82.44 (6)P—S3—Criv114.79 (11)
S1—Cr—S2i88.98 (7)Pv—S4—P107.50 (14)
S3ii—Cr—S2i87.38 (7)
Symmetry codes: (i) x, y, z+1; (ii) x1/2, y1/2, z; (iii) x+1/2, y1/2, z+1; (iv) x+1/2, y+1/2, z; (v) x+1, y, z+1.

Experimental details

Crystal data
Chemical formulaCrCsP2S7
Mr471.34
Crystal system, space groupMonoclinic, C2
Temperature (K)290
a, b, c (Å)8.5867 (7), 9.5461 (7), 6.7504 (6)
β (°) 97.572 (3)
V3)548.50 (8)
Z2
Radiation typeMo Kα
µ (mm1)5.87
Crystal size (mm)0.14 × 0.02 × 0.02
Data collection
DiffractometerRigaku R-AXIS RAPID
Absorption correctionMulti-scan
(ABSCOR; Higashi, 1995)
Tmin, Tmax0.608, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
2714, 1268, 1052
Rint0.039
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.029, 0.073, 1.18
No. of reflections1268
No. of parameters52
No. of restraints1
Δρmax, Δρmin (e Å3)1.01, 1.09
Absolute structureFlack (1983), 593 Friedel pairs
Absolute structure parameter0.01 (3)

Computer programs: RAPID-AUTO (Rigaku, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), locally modified version of ORTEP (Johnson, 1965), WinGX (Farrugia, 1999).

Selected geometric parameters (Å, º) top
Cr—S12.414 (2)P—S22.024 (3)
Cr—S22.440 (2)P—S32.012 (2)
Cr—S3i2.430 (2)P—S42.134 (2)
P—S12.025 (3)
Pii—S4—P107.50 (14)
Symmetry codes: (i) x1/2, y1/2, z; (ii) x+1, y, z+1.
 

Acknowledgements

This work was supported by 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 the Ajou University.

References

First citationCoste, S., Kopnin, E., Evain, M., Jobic, S., Payen, C. & Brec, R. (2001). J. Solid State Chem. 162, 195–203.  Web of Science CrossRef CAS Google Scholar
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First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
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First citationWang, Y. P., Lii, K. H. & Wang, S. L. (1989). Acta Cryst. C45, 1417–1418.  CrossRef CAS Web of Science IUCr Journals Google Scholar

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