trans-Cyclo­hexane-1,4-diammonium dibromide

A structure consisting of alternating organic and inorganic layers is exhibited by the title compound, C₆H₁₆N₂²⁺·2Br^-. The ammonium groups and bromide anions inter­act via hydrogen bonds to form a two-dimensional hydrogen-bond network.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.049
• wR factor = 0.113
• Data-to-parameter ratio = 35.8

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.25 Ratio

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 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
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

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: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: PLATON (Spek, 2003) and WinGX (Farrugia, 1999).

trans-1,4-Diaminocyclohexane dihydrobromide

Crystal data

C6H16N2^2+·2Br^−	F(000) = 544
Mr = 276.03	Dx = 1.754 Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 3526 reflections
a = 7.4264 (6) Å	θ = 3.8–31.8°
b = 8.9074 (6) Å	µ = 7.70 mm^−1
c = 15.8018 (14) Å	T = 295 K
V = 1045.29 (14) Å^3	Block, colourless
Z = 4	0.40 × 0.30 × 0.20 mm

Data collection

Oxford Excalibur2 diffractometer	1683 independent reflections
Radiation source: fine-focus sealed tube	1118 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.043
ω–2θ scans	θmax = 31.9°, θmin = 3.8°
Absorption correction: multi-scan (Blessing, 1995)	h = −10→8
Tmin = 0.074, Tmax = 0.216	k = −13→13
8858 measured reflections	l = −23→22

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.049	H-atom parameters constrained
wR(F^2) = 0.113	w = 1/[σ^2(Fo^2) + (0.0375P)^2 + 2.6029P] where P = (Fo^2 + 2Fc^2)/3
S = 1.08	(Δ/σ)max = 0.001
1683 reflections	Δρmax = 0.66 e Å^−3
47 parameters	Δρmin = −0.76 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.049 (2)

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
N1	−0.0929 (4)	0.6423 (3)	0.34426 (19)	0.0329 (7)
H1A	−0.0409	0.6053	0.2980	0.049*
H1B	−0.0866	0.7421	0.3433	0.049*
H1C	−0.2078	0.6140	0.3458	0.049*
C1	0.0021 (5)	0.5845 (4)	0.4208 (2)	0.0269 (7)
H1	0.1278	0.6179	0.4192	0.032*
C2	−0.0024 (5)	0.4137 (4)	0.4208 (2)	0.0321 (8)
H2A	0.0599	0.3762	0.3712	0.039*
H2B	−0.1263	0.3796	0.4182	0.039*
C3	−0.0872 (6)	0.6484 (4)	0.4994 (2)	0.0295 (8)
H3A	−0.2140	0.6222	0.4995	0.035*
H3B	−0.0775	0.7570	0.4989	0.035*
Br1	0.01149 (5)	0.00436 (4)	0.34632 (2)	0.03611 (19)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0425 (17)	0.0307 (15)	0.0257 (15)	−0.0031 (13)	0.0011 (14)	−0.0016 (13)
C1	0.0269 (16)	0.0254 (14)	0.0283 (18)	−0.0035 (14)	0.002 (2)	−0.0037 (12)
C2	0.044 (2)	0.0213 (13)	0.0306 (19)	−0.0007 (15)	0.003 (2)	−0.0076 (13)
C3	0.0342 (19)	0.0236 (15)	0.0306 (18)	0.0054 (16)	0.0020 (14)	−0.0048 (13)
Br1	0.0400 (3)	0.0321 (2)	0.0362 (3)	−0.0032 (2)	−0.00133 (15)	0.00489 (16)

Geometric parameters (Å, º)

N1—C1	1.492 (4)	C2—C3^i	1.529 (5)
N1—H1A	0.8900	C2—H2A	0.9700
N1—H1B	0.8900	C2—H2B	0.9700
N1—H1C	0.8900	C3—C2^i	1.529 (5)
C1—C3	1.518 (5)	C3—H3A	0.9700
C1—C2	1.521 (5)	C3—H3B	0.9700
C1—H1	0.9800
C1—N1—H1A	109.5	C1—C2—C3^i	110.6 (3)
C1—N1—H1B	109.5	C1—C2—H2A	109.5
H1A—N1—H1B	109.5	C3^i—C2—H2A	109.5
C1—N1—H1C	109.5	C1—C2—H2B	109.5
H1A—N1—H1C	109.5	C3^i—C2—H2B	109.5
H1B—N1—H1C	109.5	H2A—C2—H2B	108.1
N1—C1—C3	109.1 (3)	C1—C3—C2^i	110.4 (3)
N1—C1—C2	109.6 (3)	C1—C3—H3A	109.6
C3—C1—C2	111.4 (3)	C2^i—C3—H3A	109.6
N1—C1—H1	108.9	C1—C3—H3B	109.6
C3—C1—H1	108.9	C2^i—C3—H3B	109.6
C2—C1—H1	108.9	H3A—C3—H3B	108.1
N1—C1—C2—C3^i	−177.6 (3)	N1—C1—C3—C2^i	177.8 (3)
C3—C1—C2—C3^i	−56.8 (5)	C2—C1—C3—C2^i	56.7 (5)

Symmetry code: (i) −x, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Br1^ii	0.89	2.46	3.308 (3)	159
N1—H1B···Br1^iii	0.89	2.45	3.317 (3)	166
N1—H1C···Br1^iv	0.89	2.46	3.343 (3)	173

Symmetry codes: (ii) −x, y+1/2, −z+1/2; (iii) x, y+1, z; (iv) −x−1/2, y+1/2, z.