2,3,5,6-Tetra­fluoro­hydro­quinone dihydrate

2,3,5,6-Tetra­fluoro-1,4-dihydroxy­benzene easily crystallises as a dihydrate, C₆H₂F₄O₂·2H₂O. The mol­ecule exhibits approximate C_2v symmetry. The crystal packing is dominated by O—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 130 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.032
• wR factor = 0.080
• Data-to-parameter ratio = 9.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT088_ALERT_3_C Poor Data / Parameter Ratio ....................       9.27
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........          4

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

   1 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
   1 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2004); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: Stereochemical Workstation Operation Manual (Siemens, 1989) and Mercury (Version 1.4; Bruno et al., 2002); software used to prepare material for publication: SHELXL97.

2,3,5,6-tetrafluoro-1,4-dihydroxybenzene dihydrate

Crystal data

C6H2F4O2·2H2O	Dx = 1.813 Mg m^−3
Mr = 218.11	Melting point = 445–447 K
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
a = 7.6277 (9) Å	Cell parameters from 3879 reflections
b = 11.9718 (9) Å	θ = 2–25°
c = 17.5010 (13) Å	µ = 0.21 mm^−1
V = 1598.1 (3) Å^3	T = 130 K
Z = 8	Needle, colourless
F(000) = 880	0.6 × 0.15 × 0.05 mm

Data collection

Kuma KM-4-CCD κ-geometry diffractometer	1077 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.047
Graphite monochromator	θmax = 25.0°, θmin = 4.1°
ω scans	h = −9→5
7711 measured reflections	k = −14→13
1400 independent reflections	l = −20→20

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.080	All H-atom parameters refined
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0456P)^2] where P = (Fo^2 + 2Fc^2)/3
1400 reflections	(Δ/σ)max < 0.001
151 parameters	Δρmax = 0.18 e Å^−3
0 restraints	Δρmin = −0.21 e Å^−3

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
O1	0.40601 (18)	0.02068 (11)	0.36308 (8)	0.0226 (3)
H1	0.350 (3)	0.067 (2)	0.3911 (13)	0.045 (8)*
F2	0.55742 (13)	−0.12831 (9)	0.26824 (6)	0.0257 (3)
F3	0.53369 (14)	−0.10870 (9)	0.11395 (6)	0.0255 (3)
O4	0.3499 (2)	0.05894 (12)	0.04809 (8)	0.0247 (4)
H4	0.267 (3)	0.095 (2)	0.0359 (16)	0.051 (9)*
F5	0.19187 (14)	0.21639 (9)	0.14393 (6)	0.0267 (3)
F6	0.21999 (14)	0.19777 (9)	0.29851 (6)	0.0247 (3)
C1	0.3891 (2)	0.03424 (15)	0.28605 (11)	0.0179 (4)
C2	0.4669 (2)	−0.04272 (15)	0.23752 (11)	0.0184 (4)
C3	0.4541 (2)	−0.03260 (15)	0.15938 (11)	0.0185 (4)
C4	0.3597 (2)	0.05345 (15)	0.12600 (10)	0.0185 (4)
C5	0.2846 (2)	0.13111 (15)	0.17452 (11)	0.0192 (4)
C6	0.2980 (2)	0.12183 (15)	0.25274 (11)	0.0184 (4)
O1W	0.25074 (19)	0.13907 (13)	0.46949 (8)	0.0240 (3)
H1W1	0.193 (3)	0.199 (2)	0.4621 (14)	0.047 (8)*
H2W1	0.186 (4)	0.088 (3)	0.4942 (16)	0.074 (10)*
O2W	0.0852 (2)	0.15830 (12)	−0.03093 (9)	0.0255 (4)
H2W2	−0.030 (4)	0.157 (2)	−0.0149 (14)	0.053 (8)*
H1W2	0.079 (3)	0.121 (2)	−0.0707 (17)	0.057 (9)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0272 (8)	0.0231 (8)	0.0175 (8)	0.0027 (6)	0.0018 (6)	0.0011 (6)
F2	0.0265 (6)	0.0227 (6)	0.0280 (7)	0.0058 (5)	−0.0009 (5)	0.0039 (5)
F3	0.0282 (6)	0.0248 (6)	0.0234 (6)	0.0033 (5)	0.0049 (5)	−0.0050 (5)
O4	0.0279 (8)	0.0291 (8)	0.0172 (8)	0.0035 (7)	−0.0011 (6)	−0.0009 (6)
F5	0.0314 (7)	0.0233 (6)	0.0252 (6)	0.0072 (5)	−0.0038 (5)	0.0027 (5)
F6	0.0291 (7)	0.0223 (6)	0.0229 (6)	0.0043 (5)	0.0041 (5)	−0.0027 (5)
C1	0.0166 (9)	0.0216 (10)	0.0155 (10)	−0.0054 (8)	−0.0002 (8)	0.0019 (8)
C2	0.0145 (9)	0.0152 (10)	0.0256 (11)	−0.0004 (8)	−0.0002 (8)	0.0022 (8)
C3	0.0150 (10)	0.0181 (10)	0.0223 (11)	−0.0021 (8)	0.0032 (8)	−0.0035 (8)
C4	0.0168 (10)	0.0224 (10)	0.0164 (10)	−0.0033 (8)	−0.0007 (8)	−0.0003 (8)
C5	0.0186 (10)	0.0162 (10)	0.0228 (11)	−0.0008 (8)	−0.0009 (8)	0.0036 (8)
C6	0.0154 (10)	0.0170 (10)	0.0228 (11)	−0.0023 (8)	0.0035 (8)	−0.0025 (8)
O1W	0.0266 (8)	0.0233 (8)	0.0222 (8)	0.0012 (7)	0.0031 (6)	0.0013 (6)
O2W	0.0270 (9)	0.0276 (8)	0.0218 (8)	−0.0009 (6)	0.0022 (7)	−0.0050 (7)

Geometric parameters (Å, º)

O1—C1	1.364 (2)	C1—C2	1.387 (3)
O1—H1	0.85 (2)	C2—C3	1.376 (3)
F2—C2	1.348 (2)	C3—C4	1.386 (3)
F3—C3	1.353 (2)	C4—C5	1.383 (3)
O4—C4	1.367 (2)	C5—C6	1.377 (3)
O4—H4	0.80 (3)	O1W—H1W1	0.85 (3)
F5—C5	1.352 (2)	O1W—H2W1	0.90 (3)
F6—C6	1.350 (2)	O2W—H2W2	0.93 (3)
C1—C6	1.387 (3)	O2W—H1W2	0.83 (3)
C1—O1—H1	116.4 (16)	O4—C4—C5	123.88 (17)
C4—O4—H4	110 (2)	O4—C4—C3	118.97 (17)
O1—C1—C6	123.58 (17)	C5—C4—C3	117.12 (17)
O1—C1—C2	119.07 (16)	F5—C5—C6	119.54 (16)
C6—C1—C2	117.36 (17)	F5—C5—C4	118.74 (17)
F2—C2—C3	119.98 (16)	C6—C5—C4	121.69 (17)
F2—C2—C1	118.70 (16)	F6—C6—C5	120.20 (16)
C3—C2—C1	121.32 (17)	F6—C6—C1	118.73 (17)
F3—C3—C2	119.52 (16)	C5—C6—C1	121.07 (17)
F3—C3—C4	119.07 (16)	H1W1—O1W—H2W1	111 (2)
C2—C3—C4	121.40 (17)	H2W2—O2W—H1W2	101 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O1W	0.85 (2)	1.79 (2)	2.6229 (19)	165 (2)
O4—H4···O2W	0.80 (3)	1.96 (3)	2.721 (2)	159 (3)
O1W—H1W1···O2W^i	0.85 (3)	1.90 (3)	2.735 (2)	166 (2)
O1W—H2W1···O4^ii	0.90 (3)	2.01 (3)	2.846 (2)	154 (3)
O2W—H2W2···O1W^iii	0.93 (3)	1.86 (3)	2.778 (2)	170 (2)
O2W—H1W2···O1^iv	0.83 (3)	2.05 (3)	2.835 (2)	156 (3)

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