An ortho-rhom-bic polymorph of 3,4-di-amino-benzo-nitrile.

The title compound, C7H7N3, is an ortho-rhom-bic polymorph that crystallizes in the space group Pca21. The previously reported monoclinic form [Geiger & Parsons (2013 ▶) Acta Cryst. E69, o452] crystallizes in the space group P21/c (Z = 4). In the crystal, two independent HN-H⋯N C hydrogen bonds link the mol-ecules into chains along the a-glide plane. Two further independent HN-H⋯NH2 hydrogen bonds join the chains, forming a three-dimensional network.

Related literature

For the structure of the monoclinic polymorph of the title compound, see: Geiger & Parsons (2013 ▶). For the structures of the two crystalline forms of 1,2-di­amino­benzene, see: Czapik & Gdaniec (2010 ▶); Stålhandske (1981 ▶).

Experimental

Crystal data

C7H7N3

M = 133.16

Orthorhombic,

a = 17.425 (3) Å

b = 4.5225 (8) Å

c = 8.6167 (16) Å

V = 679.0 (2) Å3

Z = 4

Mo Kα radiation

μ = 0.09 mm−1

T = 200 K

0.60 × 0.30 × 0.30 mm

Data collection

Bruker SMART X2S CCD diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2010 ▶) T min = 0.84, T max = 0.98

3295 measured reflections

652 independent reflections

598 reflections with I > 2σ(I)

R int = 0.030

Refinement

R[F 2 > 2σ(F 2)] = 0.030

wR(F 2) = 0.081

S = 1.08

652 reflections

103 parameters

1 restraint

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.09 e Å−3

Δρmin = −0.14 e Å−3

Data collection: APEX2 (Bruker, 2010 ▶); cell refinement: SAINT (Bruker, 2010 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XSHELL (Bruker, 2010 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Click here for additional data file.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536813008489/qk2056sup1.cif

Click here for additional data file.

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813008489/qk2056Isup2.hkl

Click here for additional data file.

Supplementary material file. DOI: 10.1107/S1600536813008489/qk2056Isup3.mol

Click here for additional data file.

Supplementary material file. DOI: 10.1107/S1600536813008489/qk2056Isup4.cml

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

C7H7N3	Dx = 1.302 Mg m−3
Mr = 133.16	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pca21	Cell parameters from 1493 reflections
a = 17.425 (3) Å	θ = 3.3–24.9°
b = 4.5225 (8) Å	µ = 0.09 mm−1
c = 8.6167 (16) Å	T = 200 K
V = 679.0 (2) Å3	Pyramidal, colourless
Z = 4	0.60 × 0.30 × 0.30 mm
F(000) = 280

Bruker SMART X2S CCD diffractometer	652 independent reflections
Radiation source: fine-focus sealed tube	598 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.030
Detector resolution: 8.33 pixels mm-1	θmax = 25.1°, θmin = 3.3°
ω scans	h = −20→12
Absorption correction: multi-scan (SADABS; Bruker, 2010)	k = −5→5
Tmin = 0.84, Tmax = 0.98	l = −10→10
3295 measured 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)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.081	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ2(Fo2) + (0.0563P)2 + 0.0095P] where P = (Fo2 + 2Fc2)/3
652 reflections	(Δ/σ)max < 0.001
103 parameters	Δρmax = 0.09 e Å−3
1 restraint	Δρmin = −0.14 e Å−3

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
N1	0.50605 (11)	0.0476 (4)	0.6680 (3)	0.0412 (5)
H1A	0.5442 (16)	0.085 (5)	0.737 (4)	0.062*
H1B	0.5095 (15)	−0.112 (6)	0.602 (4)	0.062*
N2	0.47588 (10)	0.4365 (4)	0.9148 (2)	0.0373 (4)
H2A	0.5230 (17)	0.459 (5)	0.861 (4)	0.056*
H2B	0.4617 (15)	0.591 (6)	0.972 (4)	0.056*
N3	0.14367 (11)	0.5278 (5)	0.7794 (3)	0.0640 (7)
C1	0.43184 (9)	0.1346 (4)	0.6990 (2)	0.0327 (5)
C2	0.41581 (10)	0.3421 (4)	0.8177 (2)	0.0317 (5)
C3	0.34103 (10)	0.4346 (4)	0.8399 (3)	0.0354 (5)
H3	0.3300	0.5737	0.9194	0.043*
C4	0.28135 (10)	0.3268 (4)	0.7471 (2)	0.0381 (5)
C5	0.29684 (10)	0.1223 (5)	0.6311 (3)	0.0409 (5)
H5	0.2565	0.0481	0.5680	0.049*
C6	0.37141 (12)	0.0272 (4)	0.6082 (3)	0.0397 (5)
H6	0.3818	−0.1138	0.5292	0.048*
C7	0.20493 (12)	0.4373 (5)	0.7670 (3)	0.0461 (6)

	U11	U22	U33	U12	U13	U23
N1	0.0276 (8)	0.0464 (12)	0.0496 (12)	0.0045 (7)	0.0001 (8)	−0.0074 (9)
N2	0.0280 (9)	0.0437 (10)	0.0402 (10)	−0.0004 (7)	−0.0032 (8)	−0.0026 (9)
N3	0.0318 (10)	0.1012 (17)	0.0592 (14)	0.0168 (9)	0.0022 (10)	0.0077 (13)
C1	0.0264 (9)	0.0338 (9)	0.0378 (12)	−0.0003 (7)	0.0017 (8)	0.0061 (9)
C2	0.0266 (8)	0.0356 (10)	0.0329 (11)	−0.0004 (7)	−0.0006 (8)	0.0070 (8)
C3	0.0300 (9)	0.0424 (11)	0.0338 (11)	0.0046 (8)	0.0028 (9)	0.0049 (10)
C4	0.0265 (9)	0.0503 (13)	0.0375 (12)	0.0044 (8)	0.0010 (9)	0.0125 (10)
C5	0.0290 (10)	0.0517 (12)	0.0418 (13)	−0.0043 (8)	−0.0038 (10)	0.0077 (11)
C6	0.0354 (11)	0.0431 (11)	0.0408 (12)	−0.0012 (8)	0.0004 (10)	−0.0021 (10)
C7	0.0323 (11)	0.0666 (14)	0.0393 (13)	0.0045 (9)	0.0013 (10)	0.0087 (11)

N1—C1	1.378 (3)	C2—C3	1.382 (3)
N1—H1A	0.91 (3)	C3—C4	1.399 (3)
N1—H1B	0.92 (3)	C3—H3	0.9500
N2—C2	1.406 (3)	C4—C5	1.388 (3)
N2—H2A	0.95 (3)	C4—C7	1.433 (3)
N2—H2B	0.89 (3)	C5—C6	1.383 (3)
N3—C7	1.148 (3)	C5—H5	0.9500
C1—C6	1.399 (3)	C6—H6	0.9500
C1—C2	1.416 (3)
C1—N1—H1A	120.5 (19)	C2—C3—H3	119.5
C1—N1—H1B	113.8 (16)	C4—C3—H3	119.5
H1A—N1—H1B	120 (2)	C5—C4—C3	119.93 (16)
C2—N2—H2A	112.7 (19)	C5—C4—C7	119.96 (18)
C2—N2—H2B	111.3 (17)	C3—C4—C7	120.1 (2)
H2A—N2—H2B	115 (3)	C6—C5—C4	119.51 (19)
N1—C1—C6	120.0 (2)	C6—C5—H5	120.2
N1—C1—C2	120.94 (17)	C4—C5—H5	120.2
C6—C1—C2	119.04 (17)	C5—C6—C1	121.3 (2)
C3—C2—N2	121.9 (2)	C5—C6—H6	119.3
C3—C2—C1	119.10 (17)	C1—C6—H6	119.3
N2—C2—C1	118.95 (17)	N3—C7—C4	178.4 (3)
C2—C3—C4	121.1 (2)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···N3i	0.91 (3)	2.49 (3)	3.218 (3)	138 (2)
N1—H1B···N2ii	0.92 (3)	2.20 (3)	3.107 (3)	170 (3)
N2—H2A···N3i	0.95 (3)	2.22 (3)	3.152 (3)	168 (3)
N2—H2B···N1iii	0.89 (3)	2.41 (3)	3.210 (3)	149 (2)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯N3i	0.91 (3)	2.49 (3)	3.218 (3)	138 (2)
N1—H1B⋯N2ii	0.92 (3)	2.20 (3)	3.107 (3)	170 (3)
N2—H2A⋯N3i	0.95 (3)	2.22 (3)	3.152 (3)	168 (3)
N2—H2B⋯N1iii	0.89 (3)	2.41 (3)	3.210 (3)	149 (2)

Symmetry codes: (i) ; (ii) ; (iii) .