1,2,4-Triazolium bromide

The crystal structure of the title compound, C₂H₄N₃⁺·Br⁻, consists of cations and anions linked by N—H...Br hydrogen bonds to form chains running along the [20] direction.

Key indicators

• Single-crystal X-ray study
• T = 291 K
• Mean [sigma](N-C) = 0.003 Å
• R factor = 0.016
• wR factor = 0.042
• Data-to-parameter ratio = 11.8

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...          2
PLAT480_ALERT_4_C Long H...A H-Bond Reported H3     ..  BR      ..       2.99 Ang.

   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: 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: SHELXTL (Sheldrick, 2003); molecular graphics: SHELXTL and Mercury (Macrae et al., 2006); software used to prepare material for publication: PLATON (Spek, 2003).

1,2,4-triazolium bromide

Crystal data

C2H4N3^+·Br^−	F(000) = 288
Mr = 149.98	Dx = 2.039 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2196 reflections
a = 4.9158 (3) Å	θ = 2.9–31.3°
b = 10.3166 (6) Å	µ = 8.26 mm^−1
c = 9.8656 (6) Å	T = 291 K
β = 102.411 (7)°	Prism, colorless
V = 488.64 (5) Å^3	0.55 × 0.25 × 0.20 mm
Z = 4

Data collection

Kuma KM-4 CCD diffractometer	851 independent reflections
Radiation source: CX-Mo12x0.4-S Seifert Mo tube	792 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.015
Detector resolution: 8.2356 pixels mm^-1	θmax = 25.0°, θmin = 2.9°
ω scans	h = −5→5
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2006)	k = −12→12
Tmin = 0.035, Tmax = 0.192	l = −11→10
3233 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.016	All H-atom parameters refined
wR(F^2) = 0.042	w = 1/[σ^2(Fo^2) + (0.0291P)^2 + 0.045P] where P = (Fo^2 + 2Fc^2)/3
S = 1.09	(Δ/σ)max = 0.001
851 reflections	Δρmax = 0.39 e Å^−3
72 parameters	Δρmin = −0.22 e Å^−3
0 restraints	Extinction correction: SHELXTL, FC^*=KFC[1+0.001XFC^2Λ^3/SIN(2Θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0307 (18)

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 on F² for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating -R-factor-obs 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
Br	0.02978 (3)	0.439699 (16)	0.707333 (18)	0.03174 (13)
N1	0.3770 (4)	0.30414 (16)	0.49670 (17)	0.0334 (4)
H1	0.258 (5)	0.361 (3)	0.519 (3)	0.058 (7)*
N2	0.4859 (4)	0.19801 (18)	0.57094 (18)	0.0429 (4)
C3	0.6594 (5)	0.1523 (2)	0.5002 (2)	0.0380 (5)
H3	0.766 (5)	0.081 (2)	0.526 (3)	0.047 (7)*
N4	0.6625 (3)	0.22452 (15)	0.38778 (18)	0.0316 (4)
H4	0.747 (4)	0.2052 (19)	0.324 (2)	0.037 (6)*
C5	0.4829 (4)	0.3200 (2)	0.3866 (2)	0.0334 (4)
H5	0.428 (4)	0.387 (3)	0.317 (2)	0.045 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br	0.03490 (16)	0.03304 (16)	0.03135 (17)	0.00052 (6)	0.01611 (10)	0.00083 (6)
N1	0.0353 (8)	0.0357 (9)	0.0322 (9)	0.0025 (7)	0.0140 (7)	−0.0062 (7)
N2	0.0585 (11)	0.0429 (10)	0.0321 (9)	0.0030 (8)	0.0203 (8)	0.0063 (8)
C3	0.0465 (11)	0.0336 (10)	0.0351 (11)	0.0083 (9)	0.0115 (9)	0.0006 (8)
N4	0.0349 (8)	0.0372 (9)	0.0262 (9)	0.0027 (7)	0.0142 (7)	−0.0050 (7)
C5	0.0377 (10)	0.0355 (10)	0.0277 (10)	0.0012 (8)	0.0085 (8)	−0.0001 (9)

Geometric parameters (Å, º)

N1—N2	1.361 (3)	N1—H1	0.89 (3)
N1—C5	1.311 (3)	N4—H4	0.85 (2)
N2—C3	1.301 (3)	C3—H3	0.90 (2)
N4—C3	1.338 (3)	C5—H5	0.97 (2)
N4—C5	1.321 (3)
N2—N1—C5	111.45 (18)	N2—C3—N4	111.61 (18)
N1—N2—C3	103.29 (17)	N1—C5—N4	106.47 (18)
C3—N4—C5	107.18 (18)	N2—C3—H3	123.5 (16)
C5—N1—H1	121.2 (16)	N4—C3—H3	124.9 (16)
N2—N1—H1	127.3 (16)	N1—C5—H5	125.1 (14)
C3—N4—H4	125.1 (14)	N4—C5—H5	128.4 (14)
C5—N4—H4	127.2 (14)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Br	0.89 (3)	2.51 (3)	3.273 (2)	145 (2)
N4—H4···Br^i	0.85 (2)	2.49 (2)	3.268 (2)	154 (2)
C3—H3···Br^ii	0.90 (2)	2.99 (2)	3.685 (2)	135 (2)
C5—H5···Br^iii	0.97 (2)	2.84 (2)	3.515 (2)	127 (2)

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