Guanidinium tetra-bromidomercurate(II).

The Hg atoms in the crystal structure of the title compound, (CH(6)N(3))(2)[HgBr(4)], are tetra-hedrally coordinated by four Br atoms and the resulting [HgBr(4)](2-) tetra-hedral ions are linked to the [C(NH(2))(3)](+) ions by bromine-hydrogen bonds, forming a three-dimensional network. In the structure, the anions are located on special positions. The two different Hg⋯Br distances of 2.664 (1) and 2.559 (1) Å observed in the tetra-bromidomercurate unit are due to the connection of Br atoms to different number of H atoms.

Related literature

For the ability of the guanidinium ion to make hydrogen bonds and its unique planar shape, see: Terao et al. (2000 ▶). For related literature, see: Ishihara et al. (2002 ▶); Furukawa et al. (2005 ▶)

Experimental

Crystal data

(CH6N3)2[HgBr4]

M = 640.41

Monoclinic,

a = 10.035 (2) Å

b = 11.164 (2) Å

c = 13.358 (3) Å

β = 111.67 (3)°

V = 1390.7 (6) Å3

Z = 4

Mo Kα radiation

μ = 22.53 mm−1

T = 298 K

0.09 × 0.09 × 0.09 mm

Data collection

Stoe IPDS-I diffractometer

Absorption correction: none

9651 measured reflections

1361 independent reflections

982 reflections with I > 2σ(I)

R int = 0.093

Refinement

R[F 2 > 2σ(F 2)] = 0.030

wR(F 2) = 0.069

S = 0.90

1361 reflections

79 parameters

6 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.71 e Å−3

Δρmin = −1.03 e Å−3

Data collection: EXPOSE (Stoe & Cie, 1999 ▶); cell refinement: CELL (Stoe & Cie, 1999 ▶); data reduction: XPREP (Bruker, 2003 ▶); program(s) used to solve structure: SHELXS86 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL93 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Crystal Impact, 2008 ▶); software used to prepare material for publication: SHELXL93 (Sheldrick, 2008 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809005972/bt2874sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809005972/bt2874Isup2.hkl

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

(CH6N3)2[HgBr4]	F(000) = 1144
Mr = 640.41	Dx = 3.059 Mg m−3
Monoclinic, C2/c	Melting point: not measured K
Hall symbol: -C 2yc	Mo Kα radiation, λ = 0.71073 Å
a = 10.035 (2) Å	Cell parameters from 2000 reflections
b = 11.164 (2) Å	θ = 2.9–26.1°
c = 13.358 (3) Å	µ = 22.53 mm−1
β = 111.67 (3)°	T = 298 K
V = 1390.7 (6) Å3	Cylindric, colourless transparent
Z = 4	0.09 × 0.09 × 0.09 mm

Stoe IPDS-I diffractometer	982 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.093
graphite	θmax = 26.1°, θmin = 2.9°
imaging plate dynamic profile intergration scans	h = −12→12
9651 measured reflections	k = −13→13
1361 independent reflections	l = −16→16

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.030	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.069	w = 1/[σ2(Fo2) + (0.0376P)2] where P = (Fo2 + 2Fc2)/3
S = 0.90	(Δ/σ)max = 0.001
1361 reflections	Δρmax = 0.71 e Å−3
79 parameters	Δρmin = −1.03 e Å−3
6 restraints	Extinction correction: SHELXL93 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.00077 (10)

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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.

	x	y	z	Uiso*/Ueq
Hg1	0.5000	0.71191 (4)	0.2500	0.0577 (2)
Br1	0.30789 (8)	0.86270 (7)	0.27353 (7)	0.0555 (2)
Br2	0.38905 (10)	0.60032 (7)	0.07086 (6)	0.0635 (3)
C1	0.4454 (8)	0.8215 (6)	0.6018 (6)	0.0492 (18)
N1	0.5515 (10)	0.8736 (7)	0.5829 (6)	0.070 (2)
H1A	0.592 (10)	0.818 (7)	0.558 (8)	0.084*
H1B	0.549 (10)	0.950 (2)	0.594 (8)	0.084*
N2	0.4254 (7)	0.7072 (6)	0.5904 (6)	0.0625 (17)
H2A	0.363 (7)	0.673 (8)	0.612 (7)	0.075*
H2B	0.485 (8)	0.665 (7)	0.571 (7)	0.075*
N3	0.3560 (9)	0.8857 (7)	0.6335 (7)	0.075 (2)
H3A	0.369 (11)	0.960 (3)	0.622 (8)	0.090*
H3B	0.278 (7)	0.856 (9)	0.636 (9)	0.090*

	U11	U22	U33	U12	U13	U23
Hg1	0.0706 (3)	0.0544 (3)	0.0586 (3)	0.000	0.0359 (2)	0.000
Br1	0.0569 (4)	0.0485 (4)	0.0714 (5)	−0.0003 (3)	0.0359 (4)	−0.0070 (4)
Br2	0.0950 (6)	0.0453 (5)	0.0638 (5)	−0.0062 (4)	0.0454 (5)	−0.0100 (4)
C1	0.051 (4)	0.043 (4)	0.043 (4)	0.005 (3)	0.005 (3)	−0.006 (3)
N1	0.090 (5)	0.054 (4)	0.064 (5)	−0.021 (4)	0.026 (4)	−0.001 (4)
N2	0.058 (4)	0.052 (4)	0.081 (5)	−0.005 (3)	0.030 (4)	−0.011 (4)
N3	0.081 (5)	0.063 (5)	0.073 (5)	0.011 (5)	0.018 (5)	−0.009 (4)

Hg1—Br2	2.5593 (10)	N1—H1A	0.87 (9)
Hg1—Br2i	2.5593 (10)	N1—H1B	0.87 (9)
Hg1—Br1	2.6639 (9)	N2—H2A	0.87 (9)
Hg1—Br1i	2.6639 (9)	N2—H2B	0.87 (9)
C1—N2	1.293 (10)	N3—H3A	0.87 (9)
C1—N1	1.316 (11)	N3—H3B	0.87 (9)
C1—N3	1.334 (11)
Br2—Hg1—Br2i	121.74 (4)	C1—N1—H1A	107 (7)
Br2—Hg1—Br1	109.51 (4)	C1—N1—H1B	109 (7)
Br2i—Hg1—Br1	106.33 (3)	H1A—N1—H1B	144 (10)
Br2—Hg1—Br1i	106.33 (3)	C1—N2—H2A	120 (6)
Br2i—Hg1—Br1i	109.51 (4)	C1—N2—H2B	118 (7)
Br1—Hg1—Br1i	101.62 (4)	H2A—N2—H2B	121 (9)
N2—C1—N1	121.0 (8)	C1—N3—H3A	107 (8)
N2—C1—N3	118.3 (8)	C1—N3—H3B	122 (8)
N1—C1—N3	120.7 (7)	H3A—N3—H3B	125 (10)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Br2i	0.87 (9)	3.03 (4)	3.845 (8)	158 (9)
N1—H1B···Br1ii	0.87 (9)	2.77 (6)	3.512 (7)	144 (8)
N2—H2A···Br1iii	0.87 (9)	2.72 (4)	3.541 (7)	159 (8)
N2—H2B···Br2i	0.87 (9)	2.74 (4)	3.535 (7)	153 (8)
N3—H3A···Br1iv	0.87 (9)	3.05 (10)	3.505 (8)	115 (8)
N3—H3B···Br1iii	0.87 (9)	2.98 (8)	3.667 (9)	137 (9)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯Br2i	0.87 (9)	3.03 (4)	3.845 (8)	158 (9)
N1—H1B⋯Br1ii	0.87 (9)	2.77 (6)	3.512 (7)	144 (8)
N2—H2A⋯Br1iii	0.87 (9)	2.72 (4)	3.541 (7)	159 (8)
N2—H2B⋯Br2i	0.87 (9)	2.74 (4)	3.535 (7)	153 (8)
N3—H3A⋯Br1iv	0.87 (9)	3.05 (10)	3.505 (8)	115 (8)
N3—H3B⋯Br1iii	0.87 (9)	2.98 (8)	3.667 (9)	137 (9)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) .