2-Bromo-maleic acid.

The title compound, C(4)H(3)BrO(4), was obtained from a solution of meso-2,3-dibromo-succinic acid and vanadium(IV) oxide. The crystals are isostructural with chloro-maleic acid and the mol-ecule has two geometrically different carboxyl groups, one of which has delocalized C-O bonds and is essentially coplanar with the olefinic bond plane [give dihedral angle 15.08 (16)°], whereas the other has a localized C=O bond and forms a dihedral angle of 99.6 (3)° with the C=C bond plane. Two symmetry-independent O-H⋯O hydrogen bonds link the mol-ecules into layers parallel to the bc plane.

Related literature

For the structure of chloro­maleic acid, see: Wong et al. (2006 ▶). For the synthesis and structure of 2-bromo­fumaric acid, see: Fischer (2006 ▶). For the structure and polymorphism of maleic acid, see: Day et al. (2006 ▶). For the structure of 2-methyl­maleic acid, see: Batchelor & Jones (1998 ▶).

Experimental

Crystal data

C4H3BrO4

M = 194.97

Monoclinic,

a = 7.5074 (12) Å

b = 4.9272 (6) Å

c = 16.966 (4) Å

β = 94.213 (12)°

V = 625.9 (2) Å3

Z = 4

Mo Kα radiation

μ = 6.50 mm−1

T = 299 K

0.15 × 0.13 × 0.10 mm

Data collection

Bruker–Nonius KappaCCD diffractometer

Absorption correction: numerical HABITUS (Herrendorf & Bärnighausen, 1997 ▶) T min = 0.325, T max = 0.455

8638 measured reflections

1420 independent reflections

1046 reflections with I > 2σ(I)

R int = 0.064

Refinement

R[F 2 > 2σ(F 2)] = 0.042

wR(F 2) = 0.075

S = 1.16

1420 reflections

84 parameters

H-atom parameters constrained

Δρmax = 0.63 e Å−3

Δρmin = −0.43 e Å−3

Data collection: COLLECT (Nonius, 1999 ▶); cell refinement: DIRAX (Duisenberg, 1992 ▶); data reduction: EVALCCD (Duisenberg et al., 2003 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 1999 ▶); software used to prepare material for publication: publCIF (Westrip, 2009 ▶).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809029602/ya2098sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809029602/ya2098Isup2.hkl

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

C4H3BrO4	F(000) = 376
Mr = 194.97	Dx = 2.069 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 28 reflections
a = 7.5074 (12) Å	θ = 5.6–19.2°
b = 4.9272 (6) Å	µ = 6.50 mm−1
c = 16.966 (4) Å	T = 299 K
β = 94.213 (12)°	Block, colourless
V = 625.9 (2) Å3	0.15 × 0.13 × 0.10 mm
Z = 4

Bruker–Nonius KappaCCD diffractometer	1046 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.064
φ and ω scans	θmax = 27.5°, θmin = 4.7°
Absorption correction: numerical HABITUS (Herrendorf & Bärnighausen, 1997)	h = −9→9
Tmin = 0.325, Tmax = 0.455	k = −6→6
8638 measured reflections	l = −17→22
1420 independent reflections

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.042	H-atom parameters constrained
wR(F2) = 0.075	w = 1/[σ2(Fo2) + (0.0113P)2 + 1.1107P] where P = (Fo2 + 2Fc2)/3
S = 1.16	(Δ/σ)max = 0.001
1420 reflections	Δρmax = 0.63 e Å−3
84 parameters	Δρmin = −0.43 e Å−3
0 restraints

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.

	x	y	z	Uiso*/Ueq
C1	0.7961 (5)	0.0222 (7)	0.6839 (2)	0.0317 (8)
C2	0.6344 (4)	−0.0621 (8)	0.6312 (2)	0.0330 (8)
C3	0.6332 (5)	−0.2221 (8)	0.5700 (2)	0.0369 (9)
C4	0.7955 (5)	−0.3400 (8)	0.5399 (2)	0.0369 (9)
Br1	0.42183 (5)	0.08537 (10)	0.66527 (3)	0.05260 (18)
O1	0.8584 (3)	−0.1231 (6)	0.73530 (16)	0.0440 (7)
O2	0.8501 (4)	0.2664 (6)	0.66922 (17)	0.0493 (8)
O3	0.9456 (3)	−0.2426 (6)	0.56482 (17)	0.0466 (7)
O4	0.7746 (4)	−0.5294 (6)	0.49066 (17)	0.0482 (8)
H3A	0.5236	−0.2646	0.5439	0.044*
H2	0.9357	0.3049	0.7000	0.074*
H3	1.0256	−0.3258	0.5449	0.070*

	U11	U22	U33	U12	U13	U23
C1	0.0278 (18)	0.031 (2)	0.036 (2)	0.0046 (15)	−0.0024 (15)	−0.0024 (17)
C2	0.0275 (17)	0.031 (2)	0.039 (2)	0.0043 (15)	−0.0055 (14)	0.0019 (19)
C3	0.0288 (19)	0.035 (2)	0.045 (2)	−0.0016 (16)	−0.0066 (16)	−0.003 (2)
C4	0.0306 (19)	0.040 (2)	0.039 (2)	−0.0025 (16)	−0.0063 (16)	0.0006 (19)
Br1	0.0335 (2)	0.0616 (3)	0.0615 (3)	0.0137 (2)	−0.00437 (17)	−0.0122 (3)
O1	0.0380 (14)	0.0415 (17)	0.0498 (17)	−0.0045 (12)	−0.0160 (12)	0.0119 (14)
O2	0.0504 (17)	0.0353 (17)	0.0578 (19)	−0.0113 (13)	−0.0256 (14)	0.0076 (15)
O3	0.0332 (14)	0.0487 (18)	0.0578 (19)	−0.0067 (13)	0.0038 (13)	−0.0141 (16)
O4	0.0408 (15)	0.055 (2)	0.0476 (17)	0.0022 (13)	−0.0058 (12)	−0.0205 (15)

C1—O1	1.197 (4)	C4—O4	1.254 (5)
C1—O2	1.299 (5)	C4—O3	1.269 (4)
C1—C2	1.512 (5)	C3—H3A	0.9300
C2—C3	1.302 (5)	O2—H2	0.8200
C2—Br1	1.883 (4)	O3—H3	0.8200
C3—C4	1.475 (5)
O1—C1—O2	125.6 (3)	O4—C4—O3	124.6 (4)
O1—C1—C2	121.3 (3)	O4—C4—C3	117.3 (3)
O2—C1—C2	112.9 (3)	O3—C4—C3	118.1 (4)
C3—C2—C1	126.5 (3)	C2—C3—H3A	118.1
C3—C2—Br1	121.5 (3)	C4—C3—H3A	118.1
C1—C2—Br1	112.0 (3)	C1—O2—H2	109.5
C2—C3—C4	123.9 (3)	C4—O3—H3	109.5

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O4i	0.82	1.80	2.617 (4)	171
O2—H2···O1ii	0.82	1.86	2.681 (4)	176

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3⋯O4i	0.82	1.80	2.617 (4)	171
O2—H2⋯O1ii	0.82	1.86	2.681 (4)	176

Symmetry codes: (i) ; (ii) .