The second ortho­rhom­bic polymorph of zwitterionic metanilic acid at 130 K

The low-temperature (130 K) crystal structure of the second ortho­rhom­bic polymorph of metanilic acid (3-amino­benzene­sulfonic acid), C₆H₇NO₃S, shows the presence of two independent and conformationally similar mol­ecules of the zwitterionic acid (3-ammoniobenzenesulfonate) in the asymmetric unit; these inter­act through hydrogen bonding to give a cyclic R₂²(14) association. Peripheral hydrogen bonding gives a three-dimensional framework polymer, such as was found in the earlier polymorph [Hall & Maslen (1965), Acta Cryst. 18, 301-306], but the overall structural make-up is significantly different.

Key indicators

• Single-crystal X-ray study
• T = 130 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.041
• wR factor = 0.066
• Data-to-parameter ratio = 13.4

checkCIF/PLATON results

No syntax errors found



Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.49
           From the CIF: _reflns_number_total               2995
           Count of symmetry unique reflns         1605
           Completeness (_total/calc)            186.60%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1390
           Fraction of Friedel pairs measured     0.866
           Are heavy atom types Z>Si present        yes

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   0 ALERT level C = Check and explain
   1 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
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SMART; data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXTL (Bruker, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: PLATON.

3-ammoniobenzenesulfonate

Crystal data

C6H7NO3S	F(000) = 720
Mr = 173.20	Dx = 1.734 Mg m^−3
Orthorhombic, Pca21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2ac	Cell parameters from 2303 reflections
a = 15.9489 (15) Å	θ = 3.0–27.3°
b = 7.4448 (7) Å	µ = 0.44 mm^−1
c = 11.1716 (11) Å	T = 130 K
V = 1326.5 (2) Å^3	Plate, pale brown
Z = 8	0.45 × 0.35 × 0.10 mm

Data collection

Bruker CCD area-detector diffractometer	2995 independent reflections
Radiation source: sealed tube	2682 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.043
φ and ω scans	θmax = 27.5°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Bruker, 1999)	h = −20→17
Tmin = 0.83, Tmax = 0.96	k = −9→9
7877 measured reflections	l = −14→14

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)] = 0.041	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.066	w = 1/[σ^2(Fo^2) + (0.0222P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.94	(Δ/σ)max < 0.001
2995 reflections	Δρmax = 0.46 e Å^−3
223 parameters	Δρmin = −0.37 e Å^−3
1 restraint	Absolute structure: Flack (1985), with 200 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.03 (6)

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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
S1A	0.06856 (4)	0.49342 (9)	0.30533 (6)	0.0131 (2)
O11A	0.11737 (11)	0.3660 (2)	0.23523 (16)	0.0170 (6)
O12A	−0.00921 (12)	0.4209 (2)	0.35139 (15)	0.0183 (6)
O13A	0.05735 (11)	0.6632 (2)	0.23876 (16)	0.0179 (6)
N3A	0.35620 (15)	0.5807 (3)	0.5134 (2)	0.0143 (8)
C1A	0.13063 (16)	0.5550 (3)	0.4314 (2)	0.0124 (8)
C2A	0.21772 (16)	0.5355 (3)	0.4252 (2)	0.0127 (8)
C3A	0.26470 (16)	0.5953 (3)	0.5209 (2)	0.0121 (8)
C4A	0.22825 (18)	0.6709 (3)	0.6208 (2)	0.0155 (8)
C5A	0.14111 (17)	0.6864 (3)	0.6267 (2)	0.0176 (9)
C6A	0.09297 (17)	0.6293 (4)	0.5320 (2)	0.0158 (8)
S1B	0.35408 (4)	0.05545 (8)	0.47984 (6)	0.0134 (2)
O11B	0.36762 (11)	−0.0806 (2)	0.38737 (16)	0.0153 (6)
O12B	0.38387 (12)	−0.0040 (3)	0.59634 (17)	0.0207 (6)
O13B	0.38739 (11)	0.2289 (2)	0.44295 (17)	0.0201 (6)
N3B	0.04742 (15)	0.0212 (3)	0.3245 (2)	0.0136 (8)
C1B	0.24425 (17)	0.0824 (3)	0.4967 (2)	0.0132 (8)
C2B	0.18994 (16)	0.0342 (3)	0.4056 (2)	0.0128 (8)
C3B	0.10451 (17)	0.0633 (3)	0.4233 (2)	0.0133 (8)
C4B	0.07390 (17)	0.1356 (3)	0.5281 (2)	0.0146 (8)
C5B	0.12942 (16)	0.1820 (3)	0.6195 (3)	0.0156 (8)
C6B	0.21474 (16)	0.1568 (3)	0.6034 (2)	0.0147 (8)
H2A	0.24370	0.48280	0.35720	0.0150*
H4A	0.26210	0.71210	0.68510	0.0190*
H5A	0.11520	0.73620	0.69570	0.0210*
H6A	0.03370	0.64070	0.53540	0.0190*
H31A	0.387 (2)	0.610 (4)	0.587 (3)	0.031 (10)*
H32A	0.3718 (18)	0.471 (4)	0.494 (3)	0.036 (9)*
H33A	0.3757 (17)	0.647 (4)	0.461 (3)	0.026 (9)*
H2B	0.21020	−0.01710	0.33340	0.0150*
H4B	0.01540	0.15380	0.53800	0.0180*
H5B	0.10880	0.23060	0.69240	0.0190*
H6B	0.25300	0.19010	0.66470	0.0180*
H31B	−0.002 (2)	0.053 (4)	0.344 (3)	0.033 (10)*
H32B	0.0598 (17)	0.070 (4)	0.255 (3)	0.026 (8)*
H33B	0.0521 (17)	−0.100 (4)	0.297 (3)	0.028 (8)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1A	0.0126 (3)	0.0134 (3)	0.0133 (3)	−0.0008 (3)	−0.0002 (3)	0.0001 (3)
O11A	0.0174 (10)	0.0179 (10)	0.0158 (9)	0.0008 (8)	−0.0008 (9)	−0.0006 (8)
O12A	0.0150 (11)	0.0219 (10)	0.0179 (10)	−0.0033 (9)	−0.0012 (8)	0.0003 (8)
O13A	0.0200 (11)	0.0162 (10)	0.0174 (10)	0.0030 (8)	−0.0007 (9)	−0.0005 (8)
N3A	0.0118 (13)	0.0163 (14)	0.0149 (14)	−0.0012 (10)	0.0019 (10)	0.0026 (10)
C1A	0.0152 (15)	0.0095 (12)	0.0124 (12)	−0.0003 (10)	−0.0019 (11)	0.0018 (10)
C2A	0.0135 (14)	0.0121 (13)	0.0124 (13)	0.0015 (11)	0.0017 (11)	0.0026 (10)
C3A	0.0092 (14)	0.0112 (13)	0.0160 (14)	0.0002 (10)	0.0005 (11)	0.0058 (10)
C4A	0.0226 (16)	0.0128 (13)	0.0111 (13)	−0.0026 (12)	−0.0012 (12)	0.0011 (11)
C5A	0.0195 (16)	0.0172 (14)	0.0162 (15)	0.0009 (12)	0.0033 (12)	−0.0014 (12)
C6A	0.0112 (14)	0.0159 (14)	0.0202 (14)	0.0009 (11)	0.0032 (12)	0.0018 (12)
S1B	0.0112 (3)	0.0136 (3)	0.0153 (3)	0.0009 (3)	0.0001 (3)	−0.0004 (3)
O11B	0.0137 (10)	0.0132 (10)	0.0191 (10)	−0.0001 (8)	0.0013 (8)	0.0000 (8)
O12B	0.0171 (11)	0.0259 (10)	0.0192 (10)	0.0073 (9)	−0.0032 (8)	−0.0018 (9)
O13B	0.0145 (10)	0.0163 (10)	0.0296 (11)	−0.0015 (8)	0.0042 (8)	−0.0021 (8)
N3B	0.0118 (13)	0.0157 (13)	0.0133 (14)	−0.0001 (10)	0.0011 (10)	−0.0013 (10)
C1B	0.0104 (13)	0.0088 (12)	0.0205 (16)	−0.0003 (10)	0.0029 (12)	0.0042 (11)
C2B	0.0143 (14)	0.0128 (14)	0.0114 (13)	0.0021 (11)	0.0002 (11)	0.0000 (10)
C3B	0.0158 (15)	0.0094 (12)	0.0148 (13)	−0.0016 (11)	−0.0034 (12)	0.0048 (11)
C4B	0.0100 (14)	0.0123 (13)	0.0216 (14)	−0.0001 (11)	0.0039 (12)	0.0030 (11)
C5B	0.0183 (16)	0.0141 (14)	0.0145 (14)	−0.0010 (11)	0.0038 (12)	−0.0012 (11)
C6B	0.0158 (14)	0.0142 (14)	0.0142 (14)	0.0008 (11)	−0.0024 (12)	−0.0001 (11)

Geometric parameters (Å, º)

S1A—O11A	1.4557 (18)	C2A—C3A	1.379 (3)
S1A—O12A	1.4473 (19)	C3A—C4A	1.379 (3)
S1A—O13A	1.4774 (17)	C4A—C5A	1.396 (4)
S1A—C1A	1.782 (2)	C5A—C6A	1.375 (3)
S1B—O12B	1.455 (2)	C2A—H2A	0.9500
S1B—O13B	1.4559 (17)	C4A—H4A	0.9500
S1B—C1B	1.773 (3)	C5A—H5A	0.9500
S1B—O11B	1.4628 (18)	C6A—H6A	0.9500
N3A—C3A	1.466 (3)	C1B—C6B	1.396 (3)
N3A—H33A	0.83 (3)	C1B—C2B	1.384 (3)
N3A—H32A	0.88 (3)	C2B—C3B	1.394 (4)
N3A—H31A	0.98 (3)	C3B—C4B	1.378 (3)
N3B—C3B	1.465 (3)	C4B—C5B	1.395 (4)
N3B—H32B	0.88 (3)	C5B—C6B	1.385 (4)
N3B—H31B	0.85 (3)	C2B—H2B	0.9500
N3B—H33B	0.96 (3)	C4B—H4B	0.9500
C1A—C2A	1.398 (4)	C5B—H5B	0.9500
C1A—C6A	1.389 (3)	C6B—H6B	0.9500
O11A—S1A—O12A	113.98 (10)	C2A—C3A—C4A	122.0 (2)
O11A—S1A—O13A	110.57 (10)	C3A—C4A—C5A	119.5 (2)
O11A—S1A—C1A	107.21 (11)	C4A—C5A—C6A	119.6 (2)
O12A—S1A—O13A	113.23 (10)	C1A—C6A—C5A	120.3 (2)
O12A—S1A—C1A	106.93 (11)	C3A—C2A—H2A	121.00
O13A—S1A—C1A	104.18 (10)	C1A—C2A—H2A	121.00
O13B—S1B—C1B	106.87 (11)	C3A—C4A—H4A	120.00
O11B—S1B—C1B	107.41 (11)	C5A—C4A—H4A	120.00
O11B—S1B—O12B	111.90 (11)	C4A—C5A—H5A	120.00
O11B—S1B—O13B	111.12 (11)	C6A—C5A—H5A	120.00
O12B—S1B—O13B	113.83 (12)	C5A—C6A—H6A	120.00
O12B—S1B—C1B	105.19 (11)	C1A—C6A—H6A	120.00
H31A—N3A—H33A	106 (3)	C2B—C1B—C6B	121.3 (2)
H32A—N3A—H33A	106 (3)	S1B—C1B—C6B	117.94 (19)
C3A—N3A—H31A	115.7 (19)	S1B—C1B—C2B	120.72 (18)
C3A—N3A—H32A	111.4 (19)	C1B—C2B—C3B	117.9 (2)
C3A—N3A—H33A	111.8 (19)	N3B—C3B—C4B	120.2 (2)
H31A—N3A—H32A	106 (3)	N3B—C3B—C2B	117.9 (2)
H31B—N3B—H33B	115 (3)	C2B—C3B—C4B	121.8 (2)
C3B—N3B—H31B	109 (2)	C3B—C4B—C5B	119.6 (3)
H32B—N3B—H33B	95 (3)	C4B—C5B—C6B	119.7 (3)
H31B—N3B—H32B	109 (3)	C1B—C6B—C5B	119.7 (2)
C3B—N3B—H32B	115.9 (19)	C1B—C2B—H2B	121.00
C3B—N3B—H33B	113.3 (18)	C3B—C2B—H2B	121.00
C2A—C1A—C6A	120.7 (2)	C3B—C4B—H4B	120.00
S1A—C1A—C6A	120.1 (2)	C5B—C4B—H4B	120.00
S1A—C1A—C2A	119.09 (17)	C4B—C5B—H5B	120.00
C1A—C2A—C3A	117.9 (2)	C6B—C5B—H5B	120.00
N3A—C3A—C2A	118.2 (2)	C1B—C6B—H6B	120.00
N3A—C3A—C4A	119.8 (2)	C5B—C6B—H6B	120.00
O11A—S1A—C1A—C2A	22.8 (2)	C1A—C2A—C3A—N3A	−178.0 (2)
O12A—S1A—C1A—C2A	145.46 (18)	C1A—C2A—C3A—C4A	0.5 (3)
O13A—S1A—C1A—C2A	−94.40 (19)	C2A—C3A—C4A—C5A	0.7 (3)
O11A—S1A—C1A—C6A	−160.2 (2)	N3A—C3A—C4A—C5A	179.2 (2)
O12A—S1A—C1A—C6A	−37.6 (2)	C3A—C4A—C5A—C6A	−1.2 (3)
O13A—S1A—C1A—C6A	82.6 (2)	C4A—C5A—C6A—C1A	0.6 (4)
O12B—S1B—C1B—C2B	−141.6 (2)	S1B—C1B—C2B—C3B	−178.31 (17)
O13B—S1B—C1B—C2B	97.1 (2)	S1B—C1B—C6B—C5B	179.26 (18)
O11B—S1B—C1B—C6B	159.05 (17)	C2B—C1B—C6B—C5B	0.5 (3)
O12B—S1B—C1B—C6B	39.7 (2)	C6B—C1B—C2B—C3B	0.4 (3)
O13B—S1B—C1B—C6B	−81.6 (2)	C1B—C2B—C3B—C4B	−0.8 (3)
O11B—S1B—C1B—C2B	−22.2 (2)	C1B—C2B—C3B—N3B	176.8 (2)
C2A—C1A—C6A—C5A	0.6 (4)	N3B—C3B—C4B—C5B	−177.3 (2)
S1A—C1A—C2A—C3A	175.76 (17)	C2B—C3B—C4B—C5B	0.2 (4)
S1A—C1A—C6A—C5A	−176.3 (2)	C3B—C4B—C5B—C6B	0.7 (3)
C6A—C1A—C2A—C3A	−1.2 (3)	C4B—C5B—C6B—C1B	−1.1 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3A—H31A···O11A^i	0.98 (3)	2.46 (3)	2.979 (3)	113 (2)
N3A—H31A···O13A^i	0.98 (3)	1.95 (3)	2.935 (3)	177 (3)
N3A—H32A···O13B	0.88 (3)	1.91 (3)	2.780 (3)	171 (3)
N3A—H33A···O11B^ii	0.83 (3)	2.19 (3)	2.894 (3)	143 (3)
N3A—H33A···O12A^iii	0.83 (3)	2.26 (3)	2.808 (3)	124 (2)
N3B—H31B···O11B^iv	0.85 (3)	2.15 (3)	2.985 (3)	169 (3)
N3B—H32B···O11A	0.88 (3)	2.40 (3)	2.971 (3)	123 (2)
N3B—H32B···O12B^v	0.88 (3)	2.06 (3)	2.781 (3)	138 (2)
N3B—H33B···O13A^vi	0.96 (3)	1.88 (3)	2.837 (3)	178 (3)
C2A—H2A···O11A	0.95	2.58	2.942 (3)	103
C4B—H4B···O12B^iv	0.95	2.46	3.275 (3)	143
C5A—H5A···O11B^vii	0.95	2.55	3.392 (3)	147
C6B—H6B···O11A^i	0.95	2.57	3.430 (3)	150

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