Di-μ-iodido-bis-{[dicyclo-hexyl(phen-yl)phosphine-κP](pyridine-κN)silver(I)}.

The title compound, [Ag(2)I(2)(C(5)H(5)N)(2)(C(18)H(27)P)(2)], contains centrosymmetric dinuclear species in which each Ag atom is surrounded by a phosphine ligand, a weakly coordinating pyridine ligand and two iodide anions in a distorted tetra-hedral coordination. The two iodide anions bridge the Ag atoms, which are separated by a distance of 3.1008 (6) Å. The Ag-P distance is 2.4436 (8) Å, Ag-N is 2.386 (3)Å and the Ag-I distances are 2.8186 (4) and 2.9449 (5) Å.

Related literature

For a review of the chemistry of silver(I) complexes, see: Meijboom et al. (2009 ▶). For the coordination chemistry of AgX salts (X − = F−, Cl−, Br−, I−, BF4 −, PF6 −, NO3 − etc) with group 15 donor ligands, with the main focus on tertiary phosphines and in their context as potential anti­tumor agents, see: Berners-Price et al. (1998 ▶); Liu et al. (2008 ▶). For tertiary phosphine silver(I) complexes of mixed-base species, see: Engelhardt et al. (1989 ▶); Gotsis et al. (1989 ▶); Meijboom & Muller (2006 ▶). The unsymmetrical core (Ag—I—Ag′—I′) may be attributed to the partial separation of dimer into monomer of such complexes, see: Bowmaker et al. (1996 ▶); Meijboom & Muller (2006 ▶). For the solution behaviour of [L AgX] complexes, see: Muetterties & Alegranti (1972 ▶).

Experimental

Crystal data

[Ag2I2(C5H5N)2(C18H27P)2]

M = 1176.47

Triclinic,

a = 9.5970 (12) Å

b = 9.9816 (13) Å

c = 14.1437 (18) Å

α = 90.484 (3)°

β = 102.404 (2)°

γ = 112.704 (2)°

V = 1214.4 (3) Å3

Z = 1

Mo Kα radiation

μ = 2.18 mm−1

T = 293 K

0.3 × 0.22 × 0.09 mm

Data collection

Bruker SMART CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2004 ▶) T min = 0.562, T max = 0.828

7951 measured reflections

5723 independent reflections

4310 reflections with I > 2σ(I)

R int = 0.014

Refinement

R[F 2 > 2σ(F 2)] = 0.031

wR(F 2) = 0.073

S = 1.02

5723 reflections

244 parameters

H-atom parameters constrained

Δρmax = 0.50 e Å−3

Δρmin = −0.81 e Å−3

Data collection: SMART (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053680901099X/hg2494sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053680901099X/hg2494Isup2.hkl

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

[Ag2I2(C5H5N)2(C18H27P)2]	Z = 1
Mr = 1176.47	F(000) = 584
Triclinic, P1	Dx = 1.609 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 9.5970 (12) Å	Cell parameters from 8087 reflections
b = 9.9816 (13) Å	θ = 1.5–28°
c = 14.1437 (18) Å	µ = 2.17 mm−1
α = 90.484 (3)°	T = 293 K
β = 102.404 (2)°	Plate, colourless
γ = 112.704 (2)°	0.3 × 0.22 × 0.09 mm
V = 1214.4 (3) Å3

Bruker SMART CCD area-detector diffractometer	4310 reflections with I > 2σ(I)
ω scans	Rint = 0.014
Absorption correction: multi-scan (SADABS; Bruker, 2004)	θmax = 28°, θmin = 1.5°
Tmin = 0.562, Tmax = 0.828	h = −12→12
7951 measured reflections	k = −11→13
5723 independent reflections	l = −14→18

Refinement on F2	0 restraints
Least-squares matrix: full	H-atom parameters constrained
R[F2 > 2σ(F2)] = 0.031	w = 1/[σ2(Fo2) + (0.0363P)2] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.073	(Δ/σ)max = 0.002
S = 1.01	Δρmax = 0.50 e Å−3
5723 reflections	Δρmin = −0.81 e Å−3
244 parameters

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.

	x	y	z	Uiso*/Ueq
Ag	0.64528 (3)	0.51283 (3)	0.579194 (16)	0.04387 (8)
I	0.67657 (2)	0.67819 (2)	0.418646 (15)	0.04704 (8)
P	0.75790 (9)	0.61782 (8)	0.74849 (5)	0.03498 (17)
N	0.7116 (3)	0.3242 (3)	0.5233 (2)	0.0496 (7)
C11	0.8282 (4)	0.4979 (3)	0.8258 (2)	0.0420 (7)
H11	0.8702	0.545	0.8926	0.05*
C12	0.6951 (4)	0.3510 (4)	0.8252 (3)	0.0545 (9)
H12A	0.6467	0.3071	0.7587	0.065*
H12B	0.6171	0.366	0.8525	0.065*
C13	0.7541 (6)	0.2473 (5)	0.8845 (3)	0.0758 (12)
H13A	0.792	0.2863	0.9524	0.091*
H13B	0.6687	0.1531	0.8799	0.091*
C14	0.8837 (6)	0.2275 (5)	0.8483 (3)	0.0793 (13)
H14A	0.9225	0.1663	0.8897	0.095*
H14B	0.8427	0.1782	0.7828	0.095*
C15	1.0152 (5)	0.3712 (5)	0.8482 (3)	0.0745 (12)
H15A	1.0921	0.3552	0.8204	0.089*
H15B	1.0647	0.415	0.9147	0.089*
C16	0.9582 (4)	0.4757 (4)	0.7898 (3)	0.0535 (9)
H16A	0.9202	0.4372	0.7218	0.064*
H16B	1.0446	0.5692	0.7948	0.064*
C21	0.6083 (4)	0.6419 (3)	0.8017 (2)	0.0403 (7)
H21	0.5195	0.5473	0.7889	0.048*
C22	0.5502 (4)	0.7498 (4)	0.7480 (2)	0.0523 (8)
H22A	0.5176	0.7192	0.6787	0.063*
H22B	0.6344	0.8457	0.7585	0.063*
C23	0.4137 (5)	0.7582 (5)	0.7837 (3)	0.0680 (11)
H23A	0.3842	0.8322	0.752	0.082*
H23B	0.3253	0.6653	0.7659	0.082*
C24	0.4547 (5)	0.7946 (5)	0.8927 (3)	0.0713 (11)
H24A	0.5336	0.8932	0.9096	0.086*
H24B	0.3633	0.7912	0.9132	0.086*
C25	0.5139 (5)	0.6903 (5)	0.9458 (3)	0.0643 (10)
H25A	0.4306	0.5939	0.9355	0.077*
H25B	0.5458	0.7213	1.015	0.077*
C26	0.6511 (4)	0.6823 (4)	0.9116 (2)	0.0512 (8)
H26A	0.6819	0.6099	0.9447	0.061*
H26B	0.7386	0.776	0.9282	0.061*
C31	0.9209 (3)	0.7958 (3)	0.7758 (2)	0.0386 (7)
C32	0.9355 (4)	0.8901 (4)	0.7032 (2)	0.0473 (8)
H32	0.8637	0.8606	0.6435	0.057*
C33	1.0555 (5)	1.0272 (4)	0.7185 (3)	0.0628 (10)
H33	1.0619	1.0899	0.6698	0.075*
C34	1.1638 (5)	1.0704 (4)	0.8043 (4)	0.0713 (12)
H34	1.2464	1.1611	0.8134	0.086*
C35	1.1515 (5)	0.9803 (4)	0.8779 (3)	0.0714 (12)
H35	1.2242	1.011	0.9374	0.086*
C36	1.0303 (4)	0.8434 (4)	0.8631 (3)	0.0583 (9)
H36	1.0227	0.7828	0.913	0.07*
C41	0.6644 (5)	0.1923 (4)	0.5544 (3)	0.0605 (10)
H41	0.592	0.1694	0.5925	0.073*
C42	0.7168 (5)	0.0881 (4)	0.5333 (3)	0.0694 (11)
H42	0.6801	−0.0032	0.5562	0.083*
C43	0.8250 (5)	0.1217 (5)	0.4776 (3)	0.0759 (12)
H43	0.8629	0.0536	0.462	0.091*
C44	0.8749 (5)	0.2560 (5)	0.4461 (3)	0.0742 (12)
H44	0.9491	0.2818	0.4092	0.089*
C45	0.8155 (4)	0.3540 (4)	0.4688 (3)	0.0577 (9)
H45	0.8491	0.445	0.4453	0.069*

	U11	U22	U33	U12	U13	U23
Ag	0.05080 (15)	0.04133 (14)	0.03791 (14)	0.01641 (11)	0.01097 (11)	0.00158 (10)
I	0.04314 (13)	0.04213 (13)	0.04845 (13)	0.00716 (9)	0.01405 (9)	0.01362 (9)
P	0.0372 (4)	0.0322 (4)	0.0333 (4)	0.0111 (3)	0.0089 (3)	0.0039 (3)
N	0.0534 (17)	0.0422 (16)	0.0540 (17)	0.0210 (13)	0.0105 (13)	−0.0023 (13)
C11	0.0486 (18)	0.0421 (18)	0.0354 (16)	0.0202 (15)	0.0056 (13)	0.0075 (13)
C12	0.069 (2)	0.044 (2)	0.058 (2)	0.0240 (18)	0.0271 (18)	0.0196 (16)
C13	0.113 (4)	0.055 (2)	0.077 (3)	0.043 (3)	0.039 (3)	0.033 (2)
C14	0.116 (4)	0.065 (3)	0.083 (3)	0.061 (3)	0.029 (3)	0.025 (2)
C15	0.087 (3)	0.082 (3)	0.073 (3)	0.059 (3)	0.008 (2)	0.010 (2)
C16	0.049 (2)	0.056 (2)	0.060 (2)	0.0265 (18)	0.0120 (16)	0.0077 (17)
C21	0.0408 (16)	0.0372 (17)	0.0412 (17)	0.0113 (14)	0.0144 (13)	0.0015 (13)
C22	0.058 (2)	0.061 (2)	0.048 (2)	0.0319 (18)	0.0179 (16)	0.0101 (16)
C23	0.061 (2)	0.089 (3)	0.069 (3)	0.045 (2)	0.018 (2)	0.012 (2)
C24	0.072 (3)	0.083 (3)	0.077 (3)	0.041 (2)	0.036 (2)	0.006 (2)
C25	0.070 (3)	0.074 (3)	0.052 (2)	0.023 (2)	0.0297 (19)	0.0040 (19)
C26	0.060 (2)	0.058 (2)	0.0408 (18)	0.0264 (18)	0.0168 (16)	0.0084 (16)
C31	0.0359 (16)	0.0343 (16)	0.0443 (17)	0.0119 (13)	0.0106 (13)	0.0023 (13)
C32	0.0523 (19)	0.0419 (18)	0.0453 (18)	0.0133 (15)	0.0170 (15)	0.0050 (14)
C33	0.065 (2)	0.044 (2)	0.071 (3)	0.0054 (18)	0.029 (2)	0.0085 (18)
C34	0.051 (2)	0.041 (2)	0.107 (4)	0.0028 (17)	0.019 (2)	−0.005 (2)
C35	0.058 (2)	0.049 (2)	0.081 (3)	0.0091 (19)	−0.014 (2)	−0.013 (2)
C36	0.057 (2)	0.049 (2)	0.055 (2)	0.0164 (18)	−0.0032 (17)	0.0035 (17)
C41	0.066 (2)	0.050 (2)	0.069 (2)	0.0227 (19)	0.023 (2)	0.0046 (18)
C42	0.083 (3)	0.046 (2)	0.080 (3)	0.030 (2)	0.013 (2)	0.003 (2)
C43	0.080 (3)	0.068 (3)	0.094 (3)	0.050 (3)	0.012 (3)	−0.009 (2)
C44	0.066 (3)	0.071 (3)	0.097 (3)	0.035 (2)	0.029 (2)	−0.003 (2)
C45	0.053 (2)	0.052 (2)	0.069 (2)	0.0200 (18)	0.0172 (18)	0.0013 (18)

Ag—N	2.386 (3)	C22—H22B	0.97
Ag—P	2.4436 (8)	C23—C24	1.510 (5)
Ag—I	2.8186 (4)	C23—H23A	0.97
Ag—Ii	2.9449 (5)	C23—H23B	0.97
Ag—Agi	3.1008 (6)	C24—C25	1.503 (5)
I—Agi	2.9449 (4)	C24—H24A	0.97
P—C31	1.827 (3)	C24—H24B	0.97
P—C11	1.847 (3)	C25—C26	1.525 (5)
P—C21	1.847 (3)	C25—H25A	0.97
N—C41	1.329 (4)	C25—H25B	0.97
N—C45	1.334 (4)	C26—H26A	0.97
C11—C12	1.527 (5)	C26—H26B	0.97
C11—C16	1.532 (4)	C31—C36	1.379 (4)
C11—H11	0.98	C31—C32	1.391 (4)
C12—C13	1.536 (5)	C32—C33	1.384 (5)
C12—H12A	0.97	C32—H32	0.93
C12—H12B	0.97	C33—C34	1.358 (6)
C13—C14	1.521 (6)	C33—H33	0.93
C13—H13A	0.97	C34—C35	1.376 (6)
C13—H13B	0.97	C34—H34	0.93
C14—C15	1.501 (6)	C35—C36	1.389 (5)
C14—H14A	0.97	C35—H35	0.93
C14—H14B	0.97	C36—H36	0.93
C15—C16	1.526 (5)	C41—C42	1.374 (5)
C15—H15A	0.97	C41—H41	0.93
C15—H15B	0.97	C42—C43	1.378 (6)
C16—H16A	0.97	C42—H42	0.93
C16—H16B	0.97	C43—C44	1.353 (6)
C21—C26	1.528 (4)	C43—H43	0.93
C21—C22	1.530 (4)	C44—C45	1.376 (5)
C21—H21	0.98	C44—H44	0.93
C22—C23	1.532 (5)	C45—H45	0.93
C22—H22A	0.97
N—Ag—P	118.15 (7)	C21—C22—H22A	109.4
N—Ag—I	98.31 (7)	C23—C22—H22A	109.4
P—Ag—I	123.82 (2)	C21—C22—H22B	109.4
N—Ag—Ii	95.85 (7)	C23—C22—H22B	109.4
P—Ag—Ii	102.83 (2)	H22A—C22—H22B	108
I—Ag—Ii	114.947 (10)	C24—C23—C22	111.6 (3)
N—Ag—Agi	103.19 (7)	C24—C23—H23A	109.3
P—Ag—Agi	135.80 (2)	C22—C23—H23A	109.3
I—Ag—Agi	59.443 (10)	C24—C23—H23B	109.3
Ii—Ag—Agi	55.505 (11)	C22—C23—H23B	109.3
Ag—I—Agi	65.053 (10)	H23A—C23—H23B	108
C31—P—C11	104.16 (14)	C25—C24—C23	111.7 (3)
C31—P—C21	104.32 (14)	C25—C24—H24A	109.3
C11—P—C21	105.76 (14)	C23—C24—H24A	109.3
C31—P—Ag	119.07 (10)	C25—C24—H24B	109.3
C11—P—Ag	112.57 (10)	C23—C24—H24B	109.3
C21—P—Ag	109.89 (10)	H24A—C24—H24B	107.9
C41—N—C45	116.9 (3)	C24—C25—C26	111.9 (3)
C41—N—Ag	122.4 (2)	C24—C25—H25A	109.2
C45—N—Ag	120.1 (2)	C26—C25—H25A	109.2
C12—C11—C16	110.3 (3)	C24—C25—H25B	109.2
C12—C11—P	110.5 (2)	C26—C25—H25B	109.2
C16—C11—P	109.9 (2)	H25A—C25—H25B	107.9
C12—C11—H11	108.7	C25—C26—C21	110.9 (3)
C16—C11—H11	108.7	C25—C26—H26A	109.5
P—C11—H11	108.7	C21—C26—H26A	109.5
C11—C12—C13	110.9 (3)	C25—C26—H26B	109.5
C11—C12—H12A	109.5	C21—C26—H26B	109.5
C13—C12—H12A	109.5	H26A—C26—H26B	108.1
C11—C12—H12B	109.5	C36—C31—C32	117.7 (3)
C13—C12—H12B	109.5	C36—C31—P	124.7 (3)
H12A—C12—H12B	108	C32—C31—P	117.6 (2)
C14—C13—C12	111.5 (3)	C33—C32—C31	121.0 (3)
C14—C13—H13A	109.3	C33—C32—H32	119.5
C12—C13—H13A	109.3	C31—C32—H32	119.5
C14—C13—H13B	109.3	C34—C33—C32	120.2 (4)
C12—C13—H13B	109.3	C34—C33—H33	119.9
H13A—C13—H13B	108	C32—C33—H33	119.9
C15—C14—C13	111.6 (4)	C33—C34—C35	120.1 (3)
C15—C14—H14A	109.3	C33—C34—H34	119.9
C13—C14—H14A	109.3	C35—C34—H34	119.9
C15—C14—H14B	109.3	C34—C35—C36	119.7 (4)
C13—C14—H14B	109.3	C34—C35—H35	120.1
H14A—C14—H14B	108	C36—C35—H35	120.1
C14—C15—C16	111.4 (4)	C31—C36—C35	121.2 (4)
C14—C15—H15A	109.4	C31—C36—H36	119.4
C16—C15—H15A	109.4	C35—C36—H36	119.4
C14—C15—H15B	109.4	N—C41—C42	123.5 (4)
C16—C15—H15B	109.4	N—C41—H41	118.2
H15A—C15—H15B	108	C42—C41—H41	118.2
C15—C16—C11	112.1 (3)	C41—C42—C43	118.6 (4)
C15—C16—H16A	109.2	C41—C42—H42	120.7
C11—C16—H16A	109.2	C43—C42—H42	120.7
C15—C16—H16B	109.2	C44—C43—C42	118.5 (4)
C11—C16—H16B	109.2	C44—C43—H43	120.8
H16A—C16—H16B	107.9	C42—C43—H43	120.8
C26—C21—C22	110.5 (3)	C43—C44—C45	119.7 (4)
C26—C21—P	116.8 (2)	C43—C44—H44	120.2
C22—C21—P	110.4 (2)	C45—C44—H44	120.2
C26—C21—H21	106.2	N—C45—C44	122.8 (4)
C22—C21—H21	106.2	N—C45—H45	118.6
P—C21—H21	106.2	C44—C45—H45	118.6
C21—C22—C23	111.1 (3)
N—Ag—I—Agi	100.46 (7)	C31—P—C21—C26	−61.2 (3)
P—Ag—I—Agi	−127.34 (3)	C11—P—C21—C26	48.3 (3)
Ii—Ag—I—Agi	0	Ag—P—C21—C26	170.1 (2)
N—Ag—P—C31	102.47 (14)	C31—P—C21—C22	66.0 (3)
I—Ag—P—C31	−21.28 (12)	C11—P—C21—C22	175.6 (2)
Ii—Ag—P—C31	−153.61 (11)	Ag—P—C21—C22	−62.7 (2)
Agi—Ag—P—C31	−100.40 (12)	C26—C21—C22—C23	−55.6 (4)
N—Ag—P—C11	−19.81 (14)	P—C21—C22—C23	173.7 (3)
I—Ag—P—C11	−143.57 (11)	C21—C22—C23—C24	54.9 (5)
Ii—Ag—P—C11	84.11 (11)	C22—C23—C24—C25	−54.4 (5)
Agi—Ag—P—C11	137.32 (11)	C23—C24—C25—C26	54.9 (5)
N—Ag—P—C21	−137.39 (13)	C24—C25—C26—C21	−55.8 (4)
I—Ag—P—C21	98.85 (11)	C22—C21—C26—C25	55.9 (4)
Ii—Ag—P—C21	−33.48 (11)	P—C21—C26—C25	−176.9 (2)
Agi—Ag—P—C21	19.73 (11)	C11—P—C31—C36	−28.3 (3)
P—Ag—N—C41	68.4 (3)	C21—P—C31—C36	82.4 (3)
I—Ag—N—C41	−155.9 (3)	Ag—P—C31—C36	−154.7 (3)
Ii—Ag—N—C41	−39.6 (3)	C11—P—C31—C32	151.8 (2)
Agi—Ag—N—C41	−95.5 (3)	C21—P—C31—C32	−97.5 (3)
P—Ag—N—C45	−102.6 (3)	Ag—P—C31—C32	25.4 (3)
I—Ag—N—C45	33.1 (3)	C36—C31—C32—C33	−0.3 (5)
Ii—Ag—N—C45	149.5 (3)	P—C31—C32—C33	179.6 (3)
Agi—Ag—N—C45	93.6 (3)	C31—C32—C33—C34	1.8 (6)
C31—P—C11—C12	169.8 (2)	C32—C33—C34—C35	−2.5 (6)
C21—P—C11—C12	60.2 (3)	C33—C34—C35—C36	1.7 (6)
Ag—P—C11—C12	−59.8 (2)	C32—C31—C36—C35	−0.5 (5)
C31—P—C11—C16	−68.2 (3)	P—C31—C36—C35	179.6 (3)
C21—P—C11—C16	−177.8 (2)	C34—C35—C36—C31	−0.2 (6)
Ag—P—C11—C16	62.2 (2)	C45—N—C41—C42	−0.1 (6)
C16—C11—C12—C13	55.0 (4)	Ag—N—C41—C42	−171.3 (3)
P—C11—C12—C13	176.8 (2)	N—C41—C42—C43	0.5 (6)
C11—C12—C13—C14	−55.7 (5)	C41—C42—C43—C44	0.0 (7)
C12—C13—C14—C15	55.5 (5)	C42—C43—C44—C45	−1.0 (7)
C13—C14—C15—C16	−54.9 (5)	C41—N—C45—C44	−1.0 (6)
C14—C15—C16—C11	55.2 (4)	Ag—N—C45—C44	170.5 (3)
C12—C11—C16—C15	−55.1 (4)	C43—C44—C45—N	1.5 (7)
P—C11—C16—C15	−177.2 (3)

X	Ag—X	Ag—X	Ag···Ag	Ag—N	Ag—P	X—Ag—X	Ag—I—Ag
Ia	2.8186 (4)	2.9449 (5)	3.1008 (6)	2.386 (3)	2.4436 (8)	114.947 (10)	65.053 (10)
Ib	2.8402 (12)	2.8644 (8)	3.1130 (18)	2.392 (3)	2.4489 (12)	113.84 (4)	66.16 (4)
Ic	2.814	2.875	3.343	2.422	2.440	108.02	71.98
Brc	2.701	2.733	3.499	2.391	2.415	99.85	80.15
Clc	2.614	2.618	3.507	2.402	2.400	95.82	84.18

Table 1

Comparison of geometric parameters (Å, °) for selected [XAg(py)(P3)2] (X = Cl, Br or I) entities

X	Ag—X	Ag—X	Ag⋯Ag	Ag—N	Ag—P	X—Ag—X	Ag—I—Ag
Ia	2.8186 (4)	2.9449 (5)	3.1008 (6)	2.386 (3)	2.4436 (8)	114.947 (10)	65.053 (10)
Ib	2.8402 (12)	2.8644 (8)	3.1130 (18)	2.392 (3)	2.4489 (12)	113.84 (4)	66.16 (4)
Ic	2.814	2.875	3.343	2.422	2.440	108.02	71.98
Brc	2.701	2.733	3.499	2.391	2.415	99.85	80.15
Clc	2.614	2.618	3.507	2.402	2.400	95.82	84.18

Notes: (a) This work; (b) Meijboom & Muller (2006 ▶); (c) Gotsis et al. (1989 ▶), extracted from the Cambridge Structural Database (Allen (2002 ▶), CSD CODES are VEFRUT for X = I, VEFRON for X = Br and VEFRIH for X = Cl.