Twinning in 5-fluoro­salicylic acid: description of a new polymorph

The crystal structure of 5-fluoro­salicylic acid is known from the literature [Choudhury & Guru Row (2004). Acta Cryst. E60, o1595–o1597] as crystallizing in the monoclinic crystal system with space-group setting P2₁/n and with one mol­ecule in the asymmetric unit (polymorph I). We describe here a new polymorph which is again monoclinic but with different unit-cell parameters (polymorph II). Polymorph II has two mol­ecules in the asymmetric unit. Its structure was modelled as a twin, with a pseudo-ortho­rhom­bic C-centred twin cell.

Computing details

Data collection: APEX3 (Bruker, 2016); cell refinement: PEAKREF (Schreurs, 2016); data reduction: EVAL15 (Schreurs et al., 2010) and SADABS (Krause et al., 2015); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2017 (Sheldrick, 2015b); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: publCIF (Westrip, 2010).

5-Fluorosalicylic acid

Crystal data

C7H5FO3	F(000) = 640
Mr = 156.11	Dx = 1.653 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 23.1729 (14) Å	Cell parameters from 15239 reflections
b = 3.6802 (3) Å	θ = 1.8–27.5°
c = 15.6312 (8) Å	µ = 0.15 mm^−1
β = 109.728 (6)°	T = 110 K
V = 1254.79 (15) Å^3	Plate, colourless
Z = 8	0.27 × 0.21 × 0.04 mm

Data collection

Bruker Kappa APEXII diffractometer	2386 reflections with I > 2σ(I)
Radiation source: sealed tube	Rint = 0.064
φ and ω scans	θmax = 27.5°, θmin = 1.9°
Absorption correction: numerical (SADABS; Krause et al., 2015)	h = −30→30
Tmin = 0.694, Tmax = 1.000	k = −4→4
30602 measured reflections	l = −20→19
2884 independent reflections

Refinement

Refinement on F^2	Primary atom site location: dual
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.047	Hydrogen site location: difference Fourier map
wR(F^2) = 0.123	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0731P)^2 + 0.4868P] where P = (Fo^2 + 2Fc^2)/3
2884 reflections	(Δ/σ)max < 0.001
204 parameters	Δρmax = 0.57 e Å^−3
0 restraints	Δρmin = −0.27 e Å^−3

Special details

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. efined as a 2-component twin

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
F11	0.37637 (8)	0.4284 (5)	0.32426 (10)	0.0235 (4)
O11	0.49467 (9)	0.4087 (5)	0.11432 (12)	0.0198 (5)
H11O	0.518303	0.390822	0.083928	0.030*
O21	0.43470 (9)	0.6756 (6)	−0.01370 (14)	0.0189 (5)
O31	0.32536 (9)	0.9067 (6)	−0.02534 (13)	0.0189 (4)
H31O	0.355419	0.882858	−0.043422	0.028*
C11	0.39756 (12)	0.6221 (7)	0.10943 (18)	0.0137 (5)
C21	0.34068 (12)	0.7843 (7)	0.06108 (19)	0.0139 (6)
C31	0.29715 (12)	0.8263 (7)	0.1037 (2)	0.0170 (6)
H31	0.258631	0.933751	0.071594	0.020*
C41	0.30959 (12)	0.7131 (8)	0.19201 (19)	0.0160 (6)
H41	0.280138	0.745701	0.221390	0.019*
C51	0.36549 (12)	0.5513 (7)	0.23758 (18)	0.0166 (6)
C61	0.40960 (12)	0.5044 (7)	0.19938 (17)	0.0145 (5)
H61	0.447691	0.394723	0.232620	0.017*
C71	0.44369 (12)	0.5704 (7)	0.06512 (18)	0.0138 (5)
F12	0.12270 (8)	−0.1498 (5)	0.44878 (11)	0.0271 (5)
O12	0.00509 (9)	−0.1177 (6)	0.11867 (12)	0.0210 (5)
H12O	−0.020011	−0.100787	0.065548	0.032*
O22	0.06700 (9)	0.1506 (6)	0.05439 (14)	0.0202 (5)
O32	0.17965 (9)	0.2931 (6)	0.15292 (14)	0.0213 (5)
H32O	0.148360	0.312280	0.106257	0.032*
C12	0.10439 (12)	0.0503 (7)	0.21348 (18)	0.0149 (5)
C22	0.16289 (13)	0.1804 (7)	0.2237 (2)	0.0157 (6)
C32	0.20716 (12)	0.1943 (8)	0.3101 (2)	0.0173 (6)
H32	0.247111	0.281184	0.317137	0.021*
C42	0.19354 (14)	0.0831 (8)	0.3856 (2)	0.0207 (6)
H42	0.223687	0.092787	0.444439	0.025*
C52	0.13573 (13)	−0.0412 (7)	0.37363 (18)	0.0172 (6)
C62	0.09072 (12)	−0.0621 (7)	0.29029 (19)	0.0159 (5)
H62	0.051093	−0.150876	0.284567	0.019*
C72	0.05744 (12)	0.0321 (7)	0.12241 (18)	0.0150 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
F11	0.0365 (10)	0.0293 (9)	0.0086 (9)	−0.0006 (7)	0.0126 (7)	0.0004 (7)
O11	0.0203 (10)	0.0295 (11)	0.0129 (11)	0.0071 (8)	0.0100 (8)	0.0054 (8)
O21	0.0215 (11)	0.0258 (11)	0.0119 (11)	0.0058 (8)	0.0089 (8)	0.0068 (8)
O31	0.0213 (10)	0.0236 (10)	0.0141 (10)	0.0051 (8)	0.0088 (8)	0.0052 (8)
C11	0.0193 (13)	0.0119 (12)	0.0104 (13)	−0.0026 (10)	0.0059 (10)	−0.0022 (9)
C21	0.0204 (13)	0.0105 (12)	0.0117 (14)	−0.0009 (10)	0.0068 (11)	−0.0034 (10)
C31	0.0208 (14)	0.0125 (13)	0.0170 (15)	0.0023 (10)	0.0055 (12)	−0.0004 (10)
C41	0.0185 (12)	0.0168 (13)	0.0175 (14)	−0.0044 (10)	0.0124 (11)	−0.0049 (10)
C51	0.0264 (14)	0.0158 (12)	0.0084 (12)	−0.0058 (11)	0.0068 (11)	−0.0006 (10)
C61	0.0200 (13)	0.0131 (12)	0.0090 (12)	0.0000 (10)	0.0030 (10)	−0.0022 (10)
C71	0.0177 (13)	0.0126 (12)	0.0116 (13)	−0.0008 (10)	0.0058 (10)	−0.0031 (10)
F12	0.0381 (11)	0.0341 (11)	0.0119 (9)	−0.0026 (8)	0.0122 (8)	0.0025 (7)
O12	0.0216 (11)	0.0300 (12)	0.0122 (11)	−0.0046 (8)	0.0066 (8)	0.0000 (8)
O22	0.0263 (11)	0.0238 (11)	0.0129 (11)	−0.0046 (8)	0.0098 (9)	0.0011 (8)
O32	0.0216 (10)	0.0299 (12)	0.0149 (11)	−0.0050 (9)	0.0095 (9)	0.0011 (8)
C12	0.0227 (14)	0.0096 (12)	0.0138 (13)	0.0017 (10)	0.0080 (11)	−0.0012 (9)
C22	0.0202 (14)	0.0125 (13)	0.0175 (15)	−0.0002 (10)	0.0103 (12)	−0.0015 (10)
C32	0.0179 (14)	0.0142 (14)	0.0194 (16)	−0.0029 (10)	0.0056 (12)	−0.0020 (10)
C42	0.0308 (16)	0.0146 (14)	0.0155 (15)	0.0017 (11)	0.0061 (12)	−0.0012 (10)
C52	0.0290 (14)	0.0116 (13)	0.0140 (13)	0.0026 (11)	0.0112 (12)	0.0014 (10)
C62	0.0218 (14)	0.0114 (12)	0.0167 (13)	−0.0003 (10)	0.0095 (12)	−0.0016 (10)
C72	0.0200 (13)	0.0122 (13)	0.0159 (14)	−0.0006 (10)	0.0100 (11)	−0.0011 (10)

Geometric parameters (Å, º)

F11—C51	1.369 (3)	F12—C52	1.367 (3)
O11—C71	1.314 (3)	O12—C72	1.316 (3)
O11—H11O	0.8400	O12—H12O	0.8400
O21—C71	1.240 (3)	O22—C72	1.236 (3)
O31—C21	1.353 (3)	O32—C22	1.356 (3)
O31—H31O	0.8400	O32—H32O	0.8400
C11—C61	1.406 (4)	C12—C22	1.395 (4)
C11—C21	1.411 (4)	C12—C62	1.404 (4)
C11—C71	1.469 (4)	C12—C72	1.473 (4)
C21—C31	1.392 (4)	C22—C32	1.394 (4)
C31—C41	1.376 (4)	C32—C42	1.382 (4)
C31—H31	0.9500	C32—H32	0.9500
C41—C51	1.385 (4)	C42—C52	1.368 (4)
C41—H41	0.9500	C42—H42	0.9500
C51—C61	1.358 (4)	C52—C62	1.369 (4)
C61—H61	0.9500	C62—H62	0.9500
C71—O11—H11O	109.5	C72—O12—H12O	109.5
C21—O31—H31O	109.5	C22—O32—H32O	109.5
C61—C11—C21	120.0 (2)	C22—C12—C62	119.6 (2)
C61—C11—C71	120.1 (2)	C22—C12—C72	119.9 (2)
C21—C11—C71	119.9 (2)	C62—C12—C72	120.5 (2)
O31—C21—C31	116.9 (2)	O32—C22—C32	117.3 (3)
O31—C21—C11	123.9 (2)	O32—C22—C12	123.1 (3)
C31—C21—C11	119.2 (3)	C32—C22—C12	119.5 (3)
C41—C31—C21	120.4 (3)	C42—C32—C22	120.7 (3)
C41—C31—H31	119.8	C42—C32—H32	119.7
C21—C31—H31	119.8	C22—C32—H32	119.7
C31—C41—C51	119.3 (2)	C52—C42—C32	118.6 (3)
C31—C41—H41	120.4	C52—C42—H42	120.7
C51—C41—H41	120.4	C32—C42—H42	120.7
C61—C51—F11	118.6 (2)	F12—C52—C42	118.1 (3)
C61—C51—C41	122.7 (2)	F12—C52—C62	118.9 (2)
F11—C51—C41	118.6 (2)	C42—C52—C62	123.0 (3)
C51—C61—C11	118.4 (2)	C52—C62—C12	118.6 (2)
C51—C61—H61	120.8	C52—C62—H62	120.7
C11—C61—H61	120.8	C12—C62—H62	120.7
O21—C71—O11	122.6 (2)	O22—C72—O12	122.7 (2)
O21—C71—C11	121.5 (2)	O22—C72—C12	121.8 (2)
O11—C71—C11	115.9 (2)	O12—C72—C12	115.5 (2)
C61—C11—C21—O31	179.7 (2)	C62—C12—C22—O32	179.8 (2)
C71—C11—C21—O31	−1.5 (4)	C72—C12—C22—O32	−0.2 (4)
C61—C11—C21—C31	0.2 (4)	C62—C12—C22—C32	0.5 (4)
C71—C11—C21—C31	179.1 (2)	C72—C12—C22—C32	−179.6 (3)
O31—C21—C31—C41	−179.1 (2)	O32—C22—C32—C42	−179.8 (2)
C11—C21—C31—C41	0.4 (4)	C12—C22—C32—C42	−0.4 (4)
C21—C31—C41—C51	−1.1 (4)	C22—C32—C42—C52	0.1 (4)
C31—C41—C51—C61	1.3 (4)	C32—C42—C52—F12	−179.9 (2)
C31—C41—C51—F11	−177.7 (2)	C32—C42—C52—C62	0.3 (4)
F11—C51—C61—C11	178.3 (2)	F12—C52—C62—C12	179.9 (2)
C41—C51—C61—C11	−0.7 (4)	C42—C52—C62—C12	−0.2 (4)
C21—C11—C61—C51	−0.1 (4)	C22—C12—C62—C52	−0.2 (4)
C71—C11—C61—C51	−178.9 (2)	C72—C12—C62—C52	179.9 (2)
C61—C11—C71—O21	−179.1 (3)	C22—C12—C72—O22	−4.6 (4)
C21—C11—C71—O21	2.1 (4)	C62—C12—C72—O22	175.3 (2)
C61—C11—C71—O11	0.6 (4)	C22—C12—C72—O12	175.4 (2)
C21—C11—C71—O11	−178.3 (2)	C62—C12—C72—O12	−4.7 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O11—H11O···O21^i	0.84	1.81	2.643 (3)	176
O31—H31O···O21	0.84	1.90	2.620 (3)	144
O31—H31O···F11^ii	0.84	2.38	3.028 (3)	134
O12—H12O···O22^iii	0.84	1.83	2.659 (3)	168
O32—H32O···O22	0.84	1.88	2.597 (3)	143
O32—H32O···F12^iv	0.84	2.64	3.287 (3)	135

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