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The lattice parameters and space group for dicerium penta­thio­silicate, La2SiS5, have been reported previously [Michelet, Perez, Etienne & Darriet-Duale (1970.) C. R. Seances Acad. Sci. Ser. C 271, 513-515]. Moreover, isotypism with the La2GeS5 structure (space group P21/c) has been assigned, but a structure refinement was not performed. The present single-crystal study reveals that the two independent La atoms are surrounded by 8 and 9 S atoms, forming bi- and tricapped trigonal prisms, respectively, whereas the Si atom has a slightly distorted tetra­hedral coordination. The capped trigonal prisms are linked to tetra­hedra via corners and edges; they are also connected to each other by sharing faces.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807058606/wm2163sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807058606/wm2163Isup2.hkl
Contains datablock I

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](S-Si) = 0.002 Å
  • R factor = 0.023
  • wR factor = 0.040
  • Data-to-parameter ratio = 24.9

checkCIF/PLATON results

No syntax errors found



Alert level G PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature 293 K PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature . 293 K PLAT794_ALERT_5_G Check Predicted Bond Valency for La1 (3) 3.40 PLAT794_ALERT_5_G Check Predicted Bond Valency for La2 (3) 2.79
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 0 ALERT level C = Check and explain 4 ALERT level G = General alerts; check 2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 0 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 2 ALERT type 5 Informative message, check

Comment top

The formation of the ternary compound La2SiS5 has been reported previously (Michelet et al., 1970), but only lattice parameters were determined and isotypism with the La2GeS5 structure was established during the original study. The crystal structure of La2SiS5 has now been investigated by means of single-crystal X-ray diffraction data and is presented in this communication.

The unit cell and coordination polyhedra of the La and Si atoms are shown in Fig. 1. Six S atoms surround both independent La atoms leading to a distorted trigonal-prismatic arrangement. For La1, two additional S atoms and for La2 three additional S augment these basic polyhedra to bi- and tri-capped trigonal prisms, respectively. The Si atom has a slightly distorted tetrahedral environment of S atoms. The capped trigonal prisms are linked to the [SiS4] tetrahedra by corners and edges, whereas the capped trigonal prisms are connected to each other also by sharing faces.

Related literature top

For a previous study of the title compound, see: Michelet et al. (1970).

Experimental top

Single crystals of the title compound were grown by fusion of the elemental constituents (Alfa Aesar; purity > 99.9%wt) in the stoichiometric ratio of La:Si:S = 2:1:5 in an evacuated silica ampoule. The ampoule was heated in a tube furnace with a heating rate of 30 K/h to 1420 K and was kept at this temperature for 4 h. It was then cooled down slowly (10 K/h) to 770 K and annealed at this temperature for further 240 h and finally quenched in cold water. The obtained yellow crystals were selected from the brown-coloured compact product. The crystals had a prismatic habit and maximal lengths of 0.2 mm.

Refinement top

The highest peak is located 2.19 Å away from Si and the deepest hole 0.02 Å away from La2.

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2005); software used to prepare material for publication: publCIF (Westrip, 2007).

Figures top
[Figure 1] Fig. 1. The structure of La2SiS5 viewed along the a axis. Displacement ellipsoids are shown at the 50% probability level.
dicerium pentathiosilicate top
Crystal data top
La2SiS5F(000) = 832
Mr = 466.21Dx = 4.153 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 1465 reflections
a = 7.6208 (12) Åθ = 3.1–28.3°
b = 12.6407 (15) ŵ = 12.75 mm1
c = 7.8998 (12) ÅT = 293 K
β = 101.559 (13)°Prism, yellow
V = 745.57 (19) Å30.13 × 0.09 × 0.06 mm
Z = 4
Data collection top
KUMA KM-4 with CCD area-detector
diffractometer
1818 independent reflections
Radiation source: fine-focus sealed tube1465 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.052
Detector resolution: 1024x1024 with blocks 2x2, 33.133pixel/mm pixels mm-1θmax = 28.3°, θmin = 3.1°
ω–scanh = 109
Absorption correction: numerical
(CrysAlis-RED; Oxford Diffraction, 2006)
k = 1516
Tmin = 0.208, Tmax = 0.567l = 910
9434 measured reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullPrimary atom site location: structure-invariant direct methods
R[F2 > 2σ(F2)] = 0.023Secondary atom site location: difference Fourier map
wR(F2) = 0.040 w = 1/[σ2(Fo2) + (0.0134P)2]
where P = (Fo2 + 2Fc2)/3
S = 0.97(Δ/σ)max = 0.001
1818 reflectionsΔρmax = 0.97 e Å3
73 parametersΔρmin = 1.22 e Å3
Crystal data top
La2SiS5V = 745.57 (19) Å3
Mr = 466.21Z = 4
Monoclinic, P21/cMo Kα radiation
a = 7.6208 (12) ŵ = 12.75 mm1
b = 12.6407 (15) ÅT = 293 K
c = 7.8998 (12) Å0.13 × 0.09 × 0.06 mm
β = 101.559 (13)°
Data collection top
KUMA KM-4 with CCD area-detector
diffractometer
1818 independent reflections
Absorption correction: numerical
(CrysAlis-RED; Oxford Diffraction, 2006)
1465 reflections with I > 2σ(I)
Tmin = 0.208, Tmax = 0.567Rint = 0.052
9434 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.02373 parameters
wR(F2) = 0.0400 restraints
S = 0.97Δρmax = 0.97 e Å3
1818 reflectionsΔρmin = 1.22 e Å3
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
xyzUiso*/Ueq
La10.74054 (4)0.09529 (2)0.04559 (3)0.00735 (8)
La20.66488 (4)0.66522 (2)0.13363 (4)0.00926 (8)
Si0.83032 (18)0.38347 (10)0.09619 (16)0.0080 (3)
S11.02312 (17)0.27396 (9)0.05064 (15)0.0111 (3)
S20.92134 (17)0.50034 (9)0.28160 (15)0.0092 (3)
S30.36080 (16)0.12101 (9)0.00203 (15)0.0085 (3)
S40.67558 (17)0.47033 (9)0.11162 (15)0.0103 (3)
S50.62829 (17)0.29811 (9)0.19537 (15)0.0100 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
La10.00743 (15)0.00657 (14)0.00813 (14)0.00046 (11)0.00170 (11)0.00066 (11)
La20.00955 (16)0.00836 (15)0.00978 (14)0.00071 (12)0.00175 (12)0.00164 (11)
Si0.0087 (7)0.0075 (7)0.0078 (6)0.0011 (5)0.0019 (5)0.0009 (5)
S10.0101 (7)0.0090 (6)0.0154 (6)0.0001 (5)0.0056 (5)0.0010 (5)
S20.0098 (7)0.0081 (6)0.0094 (6)0.0015 (5)0.0011 (5)0.0023 (5)
S30.0071 (6)0.0074 (6)0.0110 (6)0.0005 (5)0.0021 (5)0.0007 (5)
S40.0119 (7)0.0107 (6)0.0078 (6)0.0013 (5)0.0012 (5)0.0003 (5)
S50.0111 (7)0.0084 (6)0.0109 (6)0.0025 (5)0.0029 (5)0.0009 (5)
Geometric parameters (Å, º) top
La1—S13.1154 (13)Si—S12.1015 (18)
La1—S2i2.9213 (13)Si—S22.0980 (17)
La1—S2ii2.9767 (13)Si—S42.1249 (18)
La1—S3iii2.8456 (12)Si—S52.1522 (19)
La1—S32.8635 (13)S1—La2v3.1226 (13)
La1—S4iv2.9670 (13)S1—La2i3.3745 (13)
La1—S53.0184 (13)S2—La1viii2.9213 (13)
La1—S5ii3.0420 (13)S2—La1iv2.9767 (13)
La2—S1v3.1226 (14)S3—La1iii2.8456 (12)
La2—S22.9350 (13)S3—La2vi2.8991 (12)
La2—S3vi2.8991 (12)S3—La2ix2.9767 (13)
La2—S3vii2.9767 (13)S4—La1ii2.9670 (13)
La2—S4vi3.0850 (13)S4—La2vi3.0850 (13)
La2—S43.1453 (12)S5—La1iv3.0420 (13)
La2—S5vi3.1040 (13)S5—La2vi3.1040 (13)
La2—S5vii3.2936 (13)S5—La2ix3.2936 (13)
La2—S1viii3.3745 (13)
S3iii—La1—S381.50 (4)S4vi—La2—S5vii71.00 (3)
S3iii—La1—S2i81.81 (3)S5vi—La2—S5vii80.42 (3)
S3—La1—S2i151.44 (4)S1v—La2—S5vii135.08 (3)
S3iii—La1—S4iv76.21 (3)S4—La2—S5vii139.07 (3)
S3—La1—S4iv77.99 (4)S3vi—La2—S1viii83.05 (3)
S2i—La1—S4iv75.61 (4)S2—La2—S1viii71.37 (3)
S3iii—La1—S2ii70.65 (3)S3vii—La2—S1viii62.28 (3)
S3—La1—S2ii124.09 (4)S4vi—La2—S1viii136.72 (3)
S2i—La1—S2ii70.84 (4)S5vi—La2—S1viii147.19 (3)
S4iv—La1—S2ii135.33 (3)S1v—La2—S1viii75.80 (3)
S3iii—La1—S5141.01 (4)S4—La2—S1viii132.30 (3)
S3—La1—S565.90 (3)S5vii—La2—S1viii85.67 (3)
S2i—La1—S5117.29 (3)S2—Si—S1116.02 (8)
S4iv—La1—S576.55 (3)S2—Si—S4103.31 (7)
S2ii—La1—S5145.78 (3)S1—Si—S4120.45 (8)
S3iii—La1—S5ii106.62 (3)S2—Si—S5105.04 (7)
S3—La1—S5ii75.35 (4)S1—Si—S5107.93 (7)
S2i—La1—S5ii131.91 (4)S4—Si—S5102.33 (8)
S4iv—La1—S5ii152.37 (4)Si—S1—La188.54 (6)
S2ii—La1—S5ii68.16 (3)Si—S1—La2v122.78 (6)
S5—La1—S5ii85.99 (2)La1—S1—La2v139.60 (4)
S3iii—La1—S1150.10 (3)Si—S1—La2i123.71 (6)
S3—La1—S1126.77 (3)La1—S1—La2i95.57 (3)
S2i—La1—S175.47 (3)La2v—S1—La2i87.44 (3)
S4iv—La1—S1115.61 (3)Si—S2—La1viii138.84 (7)
S2ii—La1—S183.54 (3)Si—S2—La296.97 (6)
S5—La1—S168.20 (3)La1viii—S2—La2110.42 (4)
S5ii—La1—S176.01 (3)Si—S2—La1iv93.92 (6)
S3vi—La2—S2143.07 (4)La1viii—S2—La1iv109.16 (4)
S3vi—La2—S3vii121.32 (3)La2—S2—La1iv101.69 (4)
S2—La2—S3vii69.46 (3)La1iii—S3—La198.50 (4)
S3vi—La2—S4vi120.21 (3)La1iii—S3—La2vi148.24 (5)
S2—La2—S4vi96.52 (3)La1—S3—La2vi98.16 (4)
S3vii—La2—S4vi74.50 (3)La1iii—S3—La2ix103.86 (4)
S3vi—La2—S5vi64.36 (3)La1—S3—La2ix99.54 (4)
S2—La2—S5vi138.56 (3)La2vi—S3—La2ix99.78 (3)
S3vii—La2—S5vi131.45 (4)Si—S4—La1ii113.10 (6)
S4vi—La2—S5vi65.14 (3)Si—S4—La2vi94.98 (6)
S3vi—La2—S1v66.39 (3)La1ii—S4—La2vi94.91 (3)
S2—La2—S1v81.49 (3)Si—S4—La290.44 (5)
S3vii—La2—S1v134.48 (3)La1ii—S4—La2144.17 (4)
S4vi—La2—S1v145.17 (3)La2vi—S4—La2110.15 (4)
S5vi—La2—S1v93.47 (4)Si—S5—La190.20 (6)
S3vi—La2—S4120.70 (3)Si—S5—La1iv91.02 (5)
S2—La2—S465.91 (3)La1—S5—La1iv133.05 (4)
S3vii—La2—S4117.61 (3)Si—S5—La2vi93.88 (5)
S4vi—La2—S469.85 (4)La1—S5—La2vi90.66 (3)
S5vi—La2—S472.80 (3)La1iv—S5—La2vi136.01 (4)
S1v—La2—S477.85 (3)Si—S5—La2ix176.92 (6)
S3vi—La2—S5vii71.04 (3)La1—S5—La2ix89.79 (3)
S2—La2—S5vii130.63 (3)La1iv—S5—La2ix86.74 (3)
S3vii—La2—S5vii61.17 (3)La2vi—S5—La2ix89.20 (3)
Symmetry codes: (i) x+2, y1/2, z+1/2; (ii) x, y+1/2, z1/2; (iii) x+1, y, z; (iv) x, y+1/2, z+1/2; (v) x+2, y+1, z; (vi) x+1, y+1, z; (vii) x+1, y+1/2, z+1/2; (viii) x+2, y+1/2, z+1/2; (ix) x+1, y1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaLa2SiS5
Mr466.21
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)7.6208 (12), 12.6407 (15), 7.8998 (12)
β (°) 101.559 (13)
V3)745.57 (19)
Z4
Radiation typeMo Kα
µ (mm1)12.75
Crystal size (mm)0.13 × 0.09 × 0.06
Data collection
DiffractometerKUMA KM-4 with CCD area-detector
diffractometer
Absorption correctionNumerical
(CrysAlis-RED; Oxford Diffraction, 2006)
Tmin, Tmax0.208, 0.567
No. of measured, independent and
observed [I > 2σ(I)] reflections
9434, 1818, 1465
Rint0.052
(sin θ/λ)max1)0.667
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.023, 0.040, 0.97
No. of reflections1818
No. of parameters73
Δρmax, Δρmin (e Å3)0.97, 1.22

Computer programs: CrysAlis CCD (Oxford Diffraction, 2006), CrysAlis RED (Oxford Diffraction, 2006), CrysAlis RED, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg, 2005), publCIF (Westrip, 2007).

Selected bond lengths (Å) top
La1—S13.1154 (13)La2—S3vii2.9767 (13)
La1—S2i2.9213 (13)La2—S4vi3.0850 (13)
La1—S2ii2.9767 (13)La2—S43.1453 (12)
La1—S3iii2.8456 (12)La2—S5vi3.1040 (13)
La1—S32.8635 (13)La2—S5vii3.2936 (13)
La1—S4iv2.9670 (13)La2—S1viii3.3745 (13)
La1—S53.0184 (13)Si—S12.1015 (18)
La1—S5ii3.0420 (13)Si—S22.0980 (17)
La2—S1v3.1226 (14)Si—S42.1249 (18)
La2—S22.9350 (13)Si—S52.1522 (19)
La2—S3vi2.8991 (12)
Symmetry codes: (i) x+2, y1/2, z+1/2; (ii) x, y+1/2, z1/2; (iii) x+1, y, z; (iv) x, y+1/2, z+1/2; (v) x+2, y+1, z; (vi) x+1, y+1, z; (vii) x+1, y+1/2, z+1/2; (viii) x+2, y+1/2, z+1/2.
 

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