Lanthanum iodide thio­silicate, La₃I[SiS₄]₂

The title compound displays isolated [SiS₄]^4- tetrahedra and a chain of I atoms along [001]. Iodine, which lies on a twofold axis, is coordinated by three lanthanum cations, one of which lies on the same twofold axis, forming an isosceles triangle. The compound is isotypic with Ce₃I[SiS₄]₂ [Gauthier et al. (1998). J. Alloys Compd, 275-277, 46-49].

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](S-Si) = 0.001 Å
• R factor = 0.019
• wR factor = 0.040
• Data-to-parameter ratio = 25.3

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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Computing details

Data collection: IPDS Software (Stoe & Cie, 1998); cell refinement: IPDS Software; data reduction: IPDS Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97.

Lanthanum(III)-iodide-di-ortho-thiosilicate

Crystal data

La3I(SiS4)2	F(000) = 1520
Mr = 856.29	Dx = 4.119 Mg m^−3
Monoclinic, C2/c	Melting point: not measured K
Hall symbol: -C 2yc	Mo Kα radiation, λ = 0.71073 Å
a = 16.110 (3) Å	Cell parameters from 11586 reflections
b = 7.9175 (12) Å	θ = 2.6–28.1°
c = 10.931 (2) Å	µ = 12.69 mm^−1
β = 97.94 (2)°	T = 293 K
V = 1380.9 (4) Å^3	Tabular, white
Z = 4	0.20 × 0.13 × 0.09 mm

Data collection

Stoe IPDS diffractometer	1671 independent reflections
Radiation source: fine-focus sealed tube	1467 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.044
Detector resolution: 60 pixels mm^-1	θmax = 28.1°, θmin = 2.6°
240 exposures, Δφ 1.2° scans	h = −21→21
Absorption correction: gaussian (X-RED; Stoe & Cie, 1998)	k = −10→10
Tmin = 0.120, Tmax = 0.256	l = −14→14
11586 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.019	w = 1/[σ^2(Fo^2) + (0.0253P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.040	(Δ/σ)max = 0.001
S = 0.95	Δρmax = 0.89 e Å^−3
1671 reflections	Δρmin = −1.22 e Å^−3
66 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.00359 (8)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
La1	0.196475 (12)	0.11952 (3)	0.67991 (2)	0.00871 (7)
La2	0.5000	0.09471 (4)	0.7500	0.01084 (9)
I	0.0000	0.98426 (5)	0.2500	0.02214 (11)
Si	0.15969 (6)	0.46257 (13)	0.02948 (9)	0.00768 (19)
S1	0.14499 (5)	0.25682 (12)	0.14650 (9)	0.01085 (19)
S2	0.28056 (5)	0.56896 (12)	0.08540 (8)	0.00946 (17)
S3	0.06842 (5)	0.65210 (12)	0.04226 (9)	0.01100 (18)
S4	0.15039 (5)	0.39868 (12)	−0.15905 (9)	0.01027 (18)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
La1	0.00974 (11)	0.00804 (11)	0.00825 (11)	0.00132 (7)	0.00092 (7)	0.00064 (8)
La2	0.00740 (13)	0.01163 (16)	0.01343 (16)	0.000	0.00126 (10)	0.000
I	0.01317 (17)	0.01203 (19)	0.0432 (3)	0.000	0.01081 (15)	0.000
Si	0.0079 (4)	0.0079 (5)	0.0071 (4)	−0.0007 (3)	0.0004 (3)	−0.0003 (4)
S1	0.0114 (4)	0.0093 (4)	0.0122 (4)	0.0015 (3)	0.0030 (3)	0.0032 (3)
S2	0.0090 (4)	0.0108 (4)	0.0083 (4)	−0.0019 (3)	0.0002 (3)	0.0007 (3)
S3	0.0087 (4)	0.0103 (4)	0.0134 (5)	0.0005 (3)	−0.0008 (3)	−0.0023 (3)
S4	0.0105 (4)	0.0117 (4)	0.0083 (4)	0.0015 (3)	−0.0001 (3)	−0.0016 (3)

Geometric parameters (Å, º)

La1—S2^i	2.9467 (10)	La2—S1^i	2.9747 (10)
La1—S4^ii	2.9828 (10)	La2—S1^viii	2.9747 (11)
La1—S3^iii	2.9885 (11)	La2—S3^vii	3.2640 (12)
La1—S2^iv	3.0006 (11)	La2—S3^iv	3.2640 (12)
La1—S4^iv	3.0580 (10)	La2—S3^viii	3.2988 (11)
La1—S2^iii	3.0614 (10)	La2—S3^i	3.2988 (11)
La1—S1^v	3.1009 (10)	La2—I^ix	3.3335 (7)
La1—S1^i	3.1213 (12)	Si—S1	2.1048 (14)
La1—I^vi	3.4571 (7)	Si—S4	2.1070 (14)
La2—S4^iv	2.9328 (10)	Si—S3	2.1189 (14)
La2—S4^vii	2.9328 (10)	Si—S2	2.1322 (13)
S2^i—La1—S4^ii	82.70 (3)	S1^i—La2—S3^viii	148.27 (3)
S2^i—La1—S3^iii	137.70 (3)	S1^viii—La2—S3^viii	67.52 (3)
S4^ii—La1—S3^iii	68.78 (3)	S3^vii—La2—S3^viii	131.03 (3)
S2^i—La1—S2^iv	139.152 (17)	S3^iv—La2—S3^viii	60.56 (3)
S4^ii—La1—S2^iv	138.01 (3)	S4^iv—La2—S3^i	65.22 (3)
S3^iii—La1—S2^iv	76.28 (3)	S4^vii—La2—S3^i	78.00 (3)
S2^i—La1—S4^iv	76.69 (3)	S1^i—La2—S3^i	67.52 (3)
S4^ii—La1—S4^iv	137.469 (19)	S1^viii—La2—S3^i	148.27 (3)
S3^iii—La1—S4^iv	144.72 (3)	S3^vii—La2—S3^i	60.56 (3)
S2^iv—La1—S4^iv	69.09 (3)	S3^iv—La2—S3^i	131.03 (3)
S2^i—La1—S2^iii	133.92 (2)	S3^viii—La2—S3^i	107.35 (4)
S4^ii—La1—S2^iii	76.11 (3)	S4^iv—La2—I^ix	121.95 (2)
S3^iii—La1—S2^iii	69.48 (3)	S4^vii—La2—I^ix	121.95 (2)
S2^iv—La1—S2^iii	70.24 (3)	S1^i—La2—I^ix	66.72 (2)
S4^iv—La1—S2^iii	92.08 (3)	S1^viii—La2—I^ix	66.722 (19)
S2^i—La1—S1^v	67.37 (3)	S3^vii—La2—I^ix	81.997 (18)
S4^ii—La1—S1^v	134.20 (3)	S3^iv—La2—I^ix	81.997 (18)
S3^iii—La1—S1^v	111.55 (3)	S3^viii—La2—I^ix	126.324 (19)
S2^iv—La1—S1^v	79.90 (3)	S3^i—La2—I^ix	126.324 (19)
S4^iv—La1—S1^v	69.34 (3)	La2^ix—I—La1^vi	103.750 (8)
S2^iii—La1—S1^v	149.10 (3)	La2^ix—I—La1^x	103.750 (8)
S2^i—La1—S1^i	68.65 (3)	La1^vi—I—La1^x	152.500 (16)
S4^ii—La1—S1^i	70.02 (3)	S1—Si—S4	114.19 (6)
S3^iii—La1—S1^i	124.48 (3)	S1—Si—S3	111.76 (6)
S2^iv—La1—S1^i	115.44 (3)	S4—Si—S3	106.16 (6)
S4^iv—La1—S1^i	67.91 (3)	S1—Si—S2	107.85 (5)
S2^iii—La1—S1^i	65.76 (3)	S4—Si—S2	108.30 (6)
S1^v—La1—S1^i	123.78 (2)	S3—Si—S2	108.42 (6)
S2^i—La1—I^vi	72.26 (3)	Si—S1—La2^i	94.90 (4)
S4^ii—La1—I^vi	74.64 (2)	Si—S1—La1^xi	139.87 (5)
S3^iii—La1—I^vi	70.48 (2)	La2^i—S1—La1^xi	123.11 (3)
S2^iv—La1—I^vi	114.93 (3)	Si—S1—La1^i	88.59 (4)
S4^iv—La1—I^vi	130.80 (2)	La2^i—S1—La1^i	105.33 (3)
S2^iii—La1—I^vi	136.692 (19)	La1^xi—S1—La1^i	92.68 (3)
S1^v—La1—I^vi	63.866 (18)	Si—S2—La1^i	92.83 (5)
S1^i—La1—I^vi	129.58 (2)	Si—S2—La1^xii	90.31 (4)
S4^iv—La2—S4^vii	116.10 (4)	La1^i—S2—La1^xii	153.07 (4)
S4^iv—La2—S1^i	71.50 (3)	Si—S2—La1^x	89.19 (4)
S4^vii—La2—S1^i	137.35 (3)	La1^i—S2—La1^x	97.03 (3)
S4^iv—La2—S1^viii	137.35 (3)	La1^xii—S2—La1^x	109.76 (3)
S4^vii—La2—S1^viii	71.50 (3)	Si—S3—La1^x	91.41 (4)
S1^i—La2—S1^viii	133.44 (4)	Si—S3—La2^xiii	88.88 (4)
S4^iv—La2—S3^vii	123.84 (3)	La1^x—S3—La2^xiii	133.89 (4)
S4^vii—La2—S3^vii	65.83 (3)	Si—S3—La2^i	85.80 (4)
S1^i—La2—S3^vii	75.49 (3)	La1^x—S3—La2^i	106.55 (3)
S1^viii—La2—S3^vii	98.08 (3)	La2^xiii—S3—La2^i	119.44 (3)
S4^iv—La2—S3^iv	65.83 (3)	Si—S4—La2^xiii	98.52 (5)
S4^vii—La2—S3^iv	123.84 (3)	Si—S4—La1^xiv	139.93 (5)
S1^i—La2—S3^iv	98.08 (3)	La2^xiii—S4—La1^xiv	116.96 (3)
S1^viii—La2—S3^iv	75.49 (3)	Si—S4—La1^xii	89.23 (4)
S3^vii—La2—S3^iv	163.99 (4)	La2^xiii—S4—La1^xii	108.02 (3)
S4^iv—La2—S3^viii	78.00 (3)	La1^xiv—S4—La1^xii	96.34 (3)
S4^vii—La2—S3^viii	65.22 (3)

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