(Bromo­meth­yl)trimethyl­ammonium tetra­fluoro­borate

In the title compound, C₄H₁₁BrN⁺·BF₄^-, both ions lie on crystallographic mirror planes, and the compound is isomorphous with the chloro­methyl analog. The C-Br distance is 1.927 (2) Å.

Key indicators

• Single-crystal X-ray study
• T = 115 K
• Mean [sigma](F-B) = 0.003 Å
• R factor = 0.027
• wR factor = 0.056
• Data-to-parameter ratio = 19.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT164_ALERT_4_C Nr. of Refined C-H H-Atoms in Heavy-At Struct...          6
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.12 Ratio

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 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
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: COLLECT (Nonius, 2000); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

(Bromomethyl)trimethylammonium tetrafluoroborate

Crystal data

C4H11BrN^+·BF4^−	F(000) = 236
Mr = 239.86	Dx = 1.897 Mg m^−3
Monoclinic, P21/m	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yb	Cell parameters from 1455 reflections
a = 5.9478 (15) Å	θ = 2.5–32.0°
b = 7.7276 (12) Å	µ = 4.90 mm^−1
c = 9.428 (2) Å	T = 115 K
β = 104.274 (9)°	Lath, colorless
V = 419.95 (15) Å^3	0.22 × 0.15 × 0.02 mm
Z = 2

Data collection

Nonius KappaCCD (with an Oxford Cryosystems Cryostream cooler) diffractometer	1519 independent reflections
Radiation source: fine-focus sealed tube	1307 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
ω scans with κ offsets	θmax = 31.8°, θmin = 3.5°
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997)	h = −8→8
Tmin = 0.410, Tmax = 0.908	k = −11→9
9258 measured reflections	l = −13→13

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)] = 0.027	Only H-atom coordinates refined
wR(F^2) = 0.056	w = 1/[σ^2(Fo^2) + (0.019P)^2 + 0.2967P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max < 0.001
1519 reflections	Δρmax = 0.48 e Å^−3
79 parameters	Δρmin = −0.63 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0090 (17)

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
Br1	0.57784 (5)	0.2500	0.49215 (3)	0.02011 (9)
F1	0.2903 (3)	0.7500	0.84247 (16)	0.0224 (3)
F2	−0.0831 (3)	0.7500	0.86145 (17)	0.0254 (3)
F3	0.01638 (18)	0.89741 (13)	0.67585 (11)	0.0218 (2)
N1	0.4747 (3)	0.2500	0.77277 (19)	0.0106 (3)
C1	0.3575 (4)	0.2500	0.6115 (2)	0.0141 (4)
H1	0.271 (3)	0.353 (3)	0.592 (2)	0.017*
C2	0.2836 (4)	0.2500	0.8520 (3)	0.0161 (4)
H2A	0.349 (6)	0.2500	0.951 (4)	0.024*
H2B	0.193 (4)	0.350 (3)	0.819 (2)	0.024*
C3	0.6206 (3)	0.4091 (2)	0.81503 (18)	0.0151 (3)
H3A	0.733 (4)	0.409 (3)	0.763 (2)	0.023*
H3B	0.686 (4)	0.401 (3)	0.914 (2)	0.023*
H3C	0.520 (4)	0.505 (3)	0.795 (2)	0.023*
B1	0.0567 (5)	0.7500	0.7637 (3)	0.0138 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.02883 (15)	0.01919 (13)	0.01553 (12)	0.000	0.01160 (9)	0.000
F1	0.0149 (7)	0.0285 (8)	0.0211 (7)	0.000	−0.0008 (6)	0.000
F2	0.0247 (8)	0.0316 (8)	0.0245 (8)	0.000	0.0150 (7)	0.000
F3	0.0258 (6)	0.0153 (5)	0.0243 (5)	0.0029 (4)	0.0062 (4)	0.0049 (4)
N1	0.0123 (9)	0.0089 (8)	0.0110 (8)	0.000	0.0039 (7)	0.000
C1	0.0134 (10)	0.0172 (10)	0.0119 (9)	0.000	0.0034 (8)	0.000
C2	0.0143 (11)	0.0199 (11)	0.0159 (10)	0.000	0.0070 (9)	0.000
C3	0.0183 (8)	0.0113 (7)	0.0160 (7)	−0.0038 (6)	0.0049 (6)	−0.0016 (6)
B1	0.0172 (12)	0.0115 (10)	0.0138 (10)	0.000	0.0057 (9)	0.000

Geometric parameters (Å, º)

Br1—C1	1.927 (2)	C1—H1	0.94 (2)
F1—B1	1.405 (3)	C2—H2A	0.92 (3)
F2—B1	1.385 (3)	C2—H2B	0.95 (2)
F3—B1	1.3938 (17)	C3—H3A	0.92 (2)
N1—C3	1.5014 (19)	C3—H3B	0.92 (2)
N1—C3^i	1.5014 (19)	C3—H3C	0.94 (2)
N1—C2	1.506 (3)	B1—F3^ii	1.3938 (17)
N1—C1	1.508 (3)
C3—N1—C3^i	109.99 (18)	N1—C3—H3A	107.6 (14)
C3—N1—C2	109.03 (11)	N1—C3—H3B	106.5 (14)
C3^i—N1—C2	109.02 (11)	H3A—C3—H3B	111.4 (19)
C3—N1—C1	111.15 (11)	N1—C3—H3C	107.2 (13)
C3^i—N1—C1	111.15 (11)	H3A—C3—H3C	113.5 (19)
C2—N1—C1	106.40 (18)	H3B—C3—H3C	110.3 (18)
N1—C1—Br1	112.14 (16)	F2—B1—F3	110.59 (14)
N1—C1—H1	106.7 (12)	F2—B1—F3^ii	110.59 (14)
Br1—C1—H1	107.8 (12)	F3—B1—F3^ii	109.62 (19)
N1—C2—H2A	109 (2)	F2—B1—F1	109.01 (19)
N1—C2—H2B	106.0 (13)	F3—B1—F1	108.48 (14)
H2A—C2—H2B	113.2 (16)	F3^ii—B1—F1	108.48 (14)
C3—N1—C1—Br1	61.43 (12)	C2—N1—C1—Br1	180.0
C3^i—N1—C1—Br1	−61.43 (12)

Symmetry codes: (i) x, −y+1/2, z; (ii) x, −y+3/2, z.