The single-crystal structure of the organic superconductor β_CO-(BEDT-TTF)₂I₃ from a powder grain

Synchrotron radiation diffraction data have been collected at 200 K on a microscopic single crystal (dimensions 12 × 10 × 2 µm) of the title compound, where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene, C₁₀H₈S₈. The quality of the diffraction data allowed a full structure refinement and enabled the determination of structural details such as the conformations of the ethylene groups as well as the occupancy of the triiodide sites. The compound was found to be slightly iodine-deficient and better described as β_CO-(BEDT-TTF)₂I_3−x [x = 0.014 (3)]. One of the ethylene groups of the BEDT-TTF cation is disordered at this temperature and exists in two distinct conformations with occupancies which are identical within the standard uncertainty.

Computing details

Cell refinement: DENZO (Otwinoski & Minor, 1993); data reduction: DENZO (Otwinoski & Minor, 1993) & CCP4 (SCALA (Evans, 1997)); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP (Johnson, 1976).

Figures

beta-co-(bis(ethylenedithio)tetrathiafulvalene)2 triiodide

Crystal data

C10H8S8·1.5I	Z = 2
Mr = 574.99	F(000) = 551
Triclinic, P1	Dx = 2.276 Mg m^−3
a = 6.585 Å	Synchrotron radiation, λ = 0.68870 Å
b = 9.038 Å	Cell parameters from 896 reflections
c = 15.205 Å	θ = 2.8–24.9°
α = 94.90°	µ = 3.81 mm^−1
β = 95.74°	T = 200 K
γ = 110.00°	Plate, brown
V = 839.1 Å^3	0.01 × 0.01 × 0.002 mm

Data collection

Princeton CCD (1024x1024 pixels) diffractometer	2746 reflections with I > 2σ(I)
Radiation source: European Synchrotron Radiation Facility	Rint = 0.032
Si(111) monochromator	θmax = 27.3°, θmin = 3.2°
ϕ scans	h = −8→7
13912 measured reflections	k = −11→11
3230 independent reflections	l = 0→20

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.081	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0097P)^2 + 5.7148P] where P = (Fo^2 + 2Fc^2)/3
3230 reflections	(Δ/σ)max = 0.002
198 parameters	Δρmax = 2.28 e Å^−3
20 restraints	Δρmin = −1.72 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
I1	0.0000	0.0000	0.0000	0.03994 (17)	0.986 (3)
I2	0.40573 (8)	0.25157 (6)	−0.01721 (3)	0.05150 (16)	0.986 (3)
S1	0.0963 (2)	−0.14611 (17)	0.43081 (8)	0.0288 (3)
S2	0.4627 (2)	−0.26148 (17)	0.44813 (8)	0.0263 (3)
S3	0.2085 (3)	0.0071 (2)	0.27059 (10)	0.0392 (4)
S4	0.6385 (3)	−0.1389 (2)	0.28793 (10)	0.0394 (4)
S5	0.2814 (2)	−0.43049 (16)	0.61967 (7)	0.0249 (3)
S6	−0.0835 (2)	−0.31358 (17)	0.59826 (7)	0.0256 (3)
S7	0.1971 (2)	−0.54159 (18)	0.79329 (8)	0.0322 (3)
S8	−0.2374 (2)	−0.39674 (18)	0.76841 (8)	0.0322 (3)
C1	0.2268 (8)	−0.2543 (6)	0.4878 (3)	0.0217 (10)
C2	0.2721 (8)	−0.1055 (6)	0.3496 (3)	0.0237 (11)
C3	0.4092 (8)	0.0204 (8)	0.1965 (3)	0.0376 (14)
H3A	0.3478	−0.0834	0.1472	0.045*
H3B	0.4265	0.1226	0.1619	0.045*
C4	0.6299 (9)	0.0335 (6)	0.2389 (4)	0.0350 (13)
H4A	0.6896	0.1347	0.2900	0.042*
H4B	0.7393	0.0559	0.1892	0.042*
C5	0.4378 (9)	−0.1576 (6)	0.3580 (3)	0.0251 (11)
C6	0.1496 (8)	−0.3259 (6)	0.5590 (3)	0.0214 (10)
C7	0.1177 (8)	−0.4523 (6)	0.7054 (3)	0.0205 (10)
C8A	−0.0351 (15)	−0.5828 (13)	0.8529 (8)	0.030 (3)	0.490 (17)
H8A	−0.1689	−0.6817	0.8160	0.036*	0.49
H8B	0.0057	−0.6168	0.9169	0.036*	0.49
C9A	−0.106 (2)	−0.4432 (14)	0.8670 (5)	0.031 (3)	0.490 (17)
H9A	0.0357	−0.3405	0.8942	0.037*	0.49
H9B	−0.2168	−0.4649	0.9161	0.037*	0.49
C8B	0.0429 (15)	−0.4891 (17)	0.8747 (5)	0.038 (4)	0.510 (17)
H8C	0.0594	−0.5481	0.9324	0.046*	0.51
H8D	0.1146	−0.3628	0.8956	0.046*	0.51
C9B	−0.1946 (15)	−0.5298 (13)	0.8437 (8)	0.032 (3)	0.510 (17)
H9C	−0.2785	−0.5228	0.9006	0.039*	0.51
H9D	−0.2623	−0.6502	0.8106	0.039*	0.51
C10	−0.0491 (8)	−0.3979 (6)	0.6958 (3)	0.0210 (10)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.0487 (4)	0.0416 (3)	0.0244 (2)	0.0114 (3)	−0.0044 (2)	0.0068 (2)
I2	0.0598 (3)	0.0495 (3)	0.0365 (2)	0.0067 (2)	0.00794 (19)	0.01076 (18)
S1	0.0301 (9)	0.0439 (8)	0.0255 (6)	0.0239 (6)	0.0136 (5)	0.0174 (5)
S2	0.0231 (8)	0.0416 (8)	0.0224 (5)	0.0181 (6)	0.0075 (4)	0.0144 (5)
S3	0.0381 (10)	0.0571 (10)	0.0433 (8)	0.0318 (8)	0.0224 (6)	0.0355 (7)
S4	0.0401 (10)	0.0586 (10)	0.0416 (7)	0.0337 (8)	0.0273 (7)	0.0305 (7)
S5	0.0244 (8)	0.0399 (8)	0.0181 (5)	0.0188 (6)	0.0060 (4)	0.0105 (5)
S6	0.0246 (8)	0.0415 (8)	0.0195 (5)	0.0197 (6)	0.0070 (4)	0.0118 (5)
S7	0.0349 (9)	0.0502 (9)	0.0230 (6)	0.0250 (7)	0.0089 (5)	0.0182 (5)
S8	0.0327 (9)	0.0481 (9)	0.0293 (6)	0.0240 (7)	0.0180 (5)	0.0198 (6)
C1	0.023 (3)	0.030 (3)	0.0167 (19)	0.014 (2)	0.0044 (17)	0.0073 (17)
C2	0.021 (3)	0.036 (3)	0.021 (2)	0.014 (2)	0.0085 (18)	0.0151 (19)
C3	0.037 (4)	0.054 (4)	0.032 (3)	0.023 (3)	0.014 (2)	0.020 (3)
C4	0.029 (4)	0.039 (3)	0.039 (3)	0.010 (3)	0.013 (2)	0.018 (2)
C5	0.025 (3)	0.035 (3)	0.022 (2)	0.014 (2)	0.0095 (18)	0.0120 (19)
C6	0.020 (3)	0.034 (3)	0.0171 (19)	0.016 (2)	0.0044 (17)	0.0073 (18)
C7	0.020 (3)	0.027 (3)	0.0148 (19)	0.008 (2)	0.0015 (16)	0.0081 (17)
C8A	0.027 (8)	0.036 (7)	0.031 (6)	0.011 (6)	0.010 (5)	0.021 (5)
C9A	0.044 (10)	0.031 (8)	0.025 (5)	0.017 (7)	0.014 (5)	0.015 (5)
C8B	0.031 (7)	0.065 (12)	0.021 (5)	0.018 (7)	0.008 (4)	0.014 (5)
C9B	0.031 (6)	0.022 (7)	0.043 (6)	0.002 (5)	0.016 (5)	0.018 (5)
C10	0.022 (3)	0.027 (3)	0.0155 (19)	0.008 (2)	0.0067 (17)	0.0074 (17)

Geometric parameters (Å, º)

I1—I2^i	2.9089 (8)	S8—C9A	1.808 (5)
I1—I2	2.9089 (8)	C1—C6	1.361 (6)
S1—C1	1.737 (5)	C2—C5	1.327 (7)
S1—C2	1.753 (5)	C3—C4	1.491 (7)
S2—C1	1.741 (5)	C3—H3A	1.0800
S2—C5	1.752 (5)	C3—H3B	1.0800
S3—C2	1.747 (5)	C4—H4A	1.0800
S3—C3	1.800 (4)	C4—H4B	1.0800
S4—C5	1.752 (5)	C7—C10	1.349 (7)
S4—C4	1.799 (4)	C8A—C9A	1.494 (7)
S5—C6	1.746 (5)	C8A—H8A	1.0800
S5—C7	1.755 (5)	C8A—H8B	1.0800
S6—C6	1.736 (5)	C9A—H9A	1.0800
S6—C10	1.754 (4)	C9A—H9B	1.0800
S7—C7	1.744 (4)	C8B—C9B	1.495 (7)
S7—C8A	1.801 (5)	C8B—H8C	1.0800
S7—C8B	1.808 (5)	C8B—H8D	1.0800
S8—C10	1.743 (5)	C9B—H9C	1.0800
S8—C9B	1.800 (5)	C9B—H9D	1.0800
I2^i—I1—I2	180.0	C1—C6—S6	122.0 (4)
C1—S1—C2	95.3 (2)	C1—C6—S5	122.8 (4)
C1—S2—C5	94.8 (2)	S6—C6—S5	115.1 (2)
C2—S3—C3	102.8 (2)	C10—C7—S7	128.6 (3)
C5—S4—C4	99.6 (2)	C10—C7—S5	117.0 (3)
C6—S5—C7	95.1 (2)	S7—C7—S5	114.4 (3)
C6—S6—C10	95.3 (2)	C9A—C8A—S7	112.3 (7)
C7—S7—C8A	101.4 (4)	C9A—C8A—H8A	109.2
C7—S7—C8B	98.7 (4)	S7—C8A—H8A	109.2
C8A—S7—C8B	27.0 (5)	C9A—C8A—H8B	109.1
C10—S8—C9B	101.3 (4)	S7—C8A—H8B	109.1
C10—S8—C9A	99.6 (4)	H8A—C8A—H8B	107.9
C9B—S8—C9A	26.4 (4)	C8A—C9A—S8	115.3 (7)
C6—C1—S1	121.7 (4)	C8A—C9A—H9A	108.4
C6—C1—S2	123.1 (4)	S8—C9A—H9A	108.4
S1—C1—S2	115.2 (2)	C8A—C9A—H9B	108.4
C5—C2—S3	129.0 (4)	S8—C9A—H9B	108.4
C5—C2—S1	116.8 (3)	H9A—C9A—H9B	107.5
S3—C2—S1	114.2 (3)	C9B—C8B—S7	115.5 (7)
C4—C3—S3	116.1 (3)	C9B—C8B—H8C	108.4
C4—C3—H3A	108.3	S7—C8B—H8C	108.4
S3—C3—H3A	108.3	C9B—C8B—H8D	108.4
C4—C3—H3B	108.3	S7—C8B—H8D	108.4
S3—C3—H3B	108.3	H8C—C8B—H8D	107.5
H3A—C3—H3B	107.4	C8B—C9B—S8	111.0 (7)
C3—C4—S4	114.6 (4)	C8B—C9B—H9C	109.4
C3—C4—H4A	108.6	S8—C9B—H9C	109.4
S4—C4—H4A	108.6	C8B—C9B—H9D	109.4
C3—C4—H4B	108.6	S8—C9B—H9D	109.4
S4—C4—H4B	108.6	H9C—C9B—H9D	108.0
H4A—C4—H4B	107.6	C7—C10—S8	128.9 (3)
C2—C5—S2	117.9 (3)	C7—C10—S6	116.9 (3)
C2—C5—S4	128.0 (4)	S8—C10—S6	114.2 (3)
S2—C5—S4	114.2 (3)
C2—S1—C1—C6	−176.7 (5)	C8A—S7—C7—C10	12.7 (7)
C2—S1—C1—S2	4.2 (3)	C8B—S7—C7—C10	−14.6 (7)
C5—S2—C1—C6	176.8 (5)	C8A—S7—C7—S5	−167.9 (5)
C5—S2—C1—S1	−4.0 (3)	C8B—S7—C7—S5	164.8 (5)
C3—S3—C2—C5	5.1 (6)	C6—S5—C7—C10	4.1 (5)
C3—S3—C2—S1	−177.9 (3)	C6—S5—C7—S7	−175.4 (3)
C1—S1—C2—C5	−2.7 (5)	C7—S7—C8A—C9A	−47.3 (9)
C1—S1—C2—S3	179.9 (3)	C8B—S7—C8A—C9A	39.6 (8)
C2—S3—C3—C4	−35.9 (5)	S7—C8A—C9A—S8	72.0 (13)
S3—C3—C4—S4	65.6 (6)	C10—S8—C9A—C8A	−49.5 (10)
C5—S4—C4—C3	−54.2 (4)	C9B—S8—C9A—C8A	46.7 (9)
S3—C2—C5—S2	177.3 (3)	C7—S7—C8B—C9B	51.7 (10)
S1—C2—C5—S2	0.3 (6)	C8A—S7—C8B—C9B	−46.3 (8)
S3—C2—C5—S4	−3.9 (9)	S7—C8B—C9B—S8	−73.9 (13)
S1—C2—C5—S4	179.1 (3)	C10—S8—C9B—C8B	47.9 (9)
C1—S2—C5—C2	2.2 (5)	C9A—S8—C9B—C8B	−40.8 (8)
C1—S2—C5—S4	−176.7 (3)	S7—C7—C10—S8	0.9 (8)
C4—S4—C5—C2	24.3 (6)	S5—C7—C10—S8	−178.5 (3)
C4—S4—C5—S2	−156.8 (3)	S7—C7—C10—S6	179.9 (3)
S1—C1—C6—S6	−0.3 (7)	S5—C7—C10—S6	0.5 (6)
S2—C1—C6—S6	178.8 (3)	C9B—S8—C10—C7	−13.9 (7)
S1—C1—C6—S5	−178.1 (3)	C9A—S8—C10—C7	12.8 (7)
S2—C1—C6—S5	1.0 (7)	C9B—S8—C10—S6	167.0 (5)
C10—S6—C6—C1	−170.3 (5)	C9A—S8—C10—S6	−166.2 (5)
C10—S6—C6—S5	7.6 (3)	C6—S6—C10—C7	−4.9 (5)
C7—S5—C6—C1	170.5 (5)	C6—S6—C10—S8	174.3 (3)
C7—S5—C6—S6	−7.4 (3)

Symmetry code: (i) −x, −y, −z.