Oxonium picrate.

The title compound, H(3)O(+)·C(6)H(2)N(3)O(7) (-), consists of one picrate anion and one oxonium cation. The oxonium cation is located on a crystallographic twofold axis and both its H atoms are disordered, each over two symmetry-equivalent positions with occupancy ratios of 0.75. The picrate anions are also located on twofold axes bis-ecting the phenolate and p-nitro groups. π-π inter-actions between the rings of the picrates [centroid-to-centroid distances of 3.324 (2) Å] connect the anions to form stacks along the a-axis direction. The stacks are further joined together by the protonated water mol-ecules through hydrogen bonds to form two-dimensional sheets extending parallel to the ab plane. The sheets are stacked on top of each other along the c-axis direction and connected through C-H⋯O inter-actions between the CH groups of the benzene rings and the picrate nitro groups, with C⋯O distances of 3.450 (2) Å.

Related literature

For general background to organic salts of n class="Chemical">picric acid, see Jin et al. (2010 ▶); Harrison et al. (2007 ▶); Muthamizhchelvan et al. (2005 ▶); Smith et al. (2004 ▶).

Experimental

Crystal data

H3O+·C6n class="Species">H2N3O7 −

M = 247.13

Orthorhombic,

a = 7.1510 (6) Å

b = 19.80820 (18) Å

c = 13.50610 (12) Å

V = 1913.12 (16) Å3

Z = 8

Mo Kα radiation

μ = 0.16 mm−1

T = 298 K

0.45 × 0.34 × 0.31 mm

Data collection

Bruker SMART CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2002 ▶) T min = 0.936, T max = 0.951

3842 measured reflections

848 independent reflections

654 reflections with I > 2σ(I)

R int = 0.044

Refinement

R[F 2 > 2σ(F 2)] = 0.044

wR(F 2) = 0.140

S = 1.12

848 reflections

89 parameters

2 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.21 e Å−3

Δρmin = −0.41 e Å−3

Data collection: SMART (Bruker, 2002 ▶); cell refinement: SAINT (Bruker, 2002 ▶); data reduction: SAIn class="Chemical">NT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811022574/zl2375sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811022574/zl2375Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536811022574/zl2375Isup3.cml

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

H3O+·C6H2N3O7−	Dx = 1.716 Mg m−3
Mr = 247.13	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Ibca	Cell parameters from 1867 reflections
a = 7.1510 (6) Å	θ = 1.5–25.0°
b = 19.80820 (18) Å	µ = 0.16 mm−1
c = 13.50610 (12) Å	T = 298 K
V = 1913.12 (16) Å3	Block, yellow
Z = 8	0.45 × 0.34 × 0.31 mm
F(000) = 1008

Bruker SMART CCD area-detector diffractometer	848 independent reflections
Radiation source: fine-focus sealed tube	654 reflections with I > 2σ(I)
graphite	Rint = 0.044
φ and ω scans	θmax = 25.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −8→8
Tmin = 0.936, Tmax = 0.951	k = −22→23
3842 measured reflections	l = −16→6

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.044	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.140	w = 1/[σ2(Fo2) + (0.0677P)2 + 3.1011P] where P = (Fo2 + 2Fc2)/3
S = 1.12	(Δ/σ)max < 0.001
848 reflections	Δρmax = 0.21 e Å−3
89 parameters	Δρmin = −0.41 e Å−3
2 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.039 (4)

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	Occ. (<1)
N1	0.3838 (3)	0.11353 (11)	0.17214 (16)	0.0328 (7)
N2	0.2500	−0.09568 (15)	0.0000	0.0361 (8)
O1	0.2500	0.18513 (12)	0.0000	0.0369 (8)
O2	0.3327 (3)	0.17048 (10)	0.19325 (15)	0.0502 (7)
O3	0.4947 (3)	0.08131 (11)	0.22328 (15)	0.0497 (7)
O4	0.3100 (4)	−0.12491 (10)	0.07276 (19)	0.0630 (8)
O5	0.0000	0.2500	0.1338 (2)	0.0489 (9)
H5A	0.089 (6)	0.233 (3)	0.091 (3)	0.073*	0.75
H5B	0.052 (7)	0.279 (2)	0.177 (3)	0.073*	0.75
C1	0.2500	0.12179 (17)	0.0000	0.0270 (8)
C2	0.3107 (4)	0.08102 (13)	0.08289 (17)	0.0270 (7)
C3	0.3134 (4)	0.01147 (13)	0.08305 (17)	0.0286 (7)
H3	0.3569	−0.0122	0.1378	0.034*
C4	0.2500	−0.02233 (17)	0.0000	0.0282 (8)

	U11	U22	U33	U12	U13	U23
N1	0.0376 (14)	0.0358 (13)	0.0250 (12)	−0.0067 (10)	−0.0014 (10)	0.0001 (9)
N2	0.0350 (19)	0.0269 (16)	0.046 (2)	0.000	0.0059 (15)	0.000
O1	0.0587 (19)	0.0226 (13)	0.0295 (14)	0.000	0.0085 (13)	0.000
O2	0.0748 (17)	0.0372 (12)	0.0387 (12)	0.0047 (10)	−0.0128 (11)	−0.0126 (9)
O3	0.0569 (15)	0.0538 (13)	0.0385 (12)	0.0006 (11)	−0.0193 (10)	0.0019 (9)
O4	0.096 (2)	0.0300 (12)	0.0629 (15)	0.0117 (11)	−0.0140 (14)	0.0089 (10)
O5	0.061 (2)	0.0414 (17)	0.0443 (18)	−0.0008 (15)	0.000	0.000
C1	0.0273 (19)	0.0275 (18)	0.0260 (18)	0.000	0.0050 (14)	0.000
C2	0.0287 (14)	0.0305 (14)	0.0217 (13)	−0.0032 (10)	0.0009 (10)	−0.0014 (9)
C3	0.0279 (14)	0.0303 (14)	0.0275 (13)	0.0010 (11)	−0.0001 (11)	0.0051 (10)
C4	0.0262 (19)	0.0248 (17)	0.0337 (19)	0.000	0.0041 (15)	0.000

N1—O2	1.220 (3)	O5—H5B	0.91 (2)
N1—O3	1.230 (3)	C1—C2	1.447 (3)
N1—C2	1.463 (3)	C1—C2i	1.447 (3)
N2—O4	1.219 (3)	C2—C3	1.378 (4)
N2—O4i	1.219 (3)	C3—C4	1.383 (3)
N2—C4	1.453 (5)	C3—H3	0.9300
O1—C1	1.255 (4)	C4—C3i	1.383 (3)
O5—H5A	0.92 (2)
O2—N1—O3	122.8 (2)	C3—C2—C1	124.3 (2)
O2—N1—C2	119.5 (2)	C3—C2—N1	115.7 (2)
O3—N1—C2	117.7 (2)	C1—C2—N1	119.9 (2)
O4—N2—O4i	123.3 (3)	C2—C3—C4	118.6 (2)
O4—N2—C4	118.37 (17)	C2—C3—H3	120.7
O4i—N2—C4	118.37 (17)	C4—C3—H3	120.7
H5A—O5—H5B	111 (5)	C3i—C4—C3	122.1 (3)
O1—C1—C2	123.92 (15)	C3i—C4—N2	118.97 (16)
O1—C1—C2i	123.92 (15)	C3—C4—N2	118.97 (16)
C2—C1—C2i	112.2 (3)
O1—C1—C2—C3	−179.13 (18)	C1—C2—C3—C4	−1.7 (3)
C2i—C1—C2—C3	0.87 (18)	N1—C2—C3—C4	−178.59 (19)
O1—C1—C2—N1	−2.4 (3)	C2—C3—C4—C3i	0.81 (17)
C2i—C1—C2—N1	177.6 (3)	C2—C3—C4—N2	−179.19 (17)
O2—N1—C2—C3	−155.8 (3)	O4—N2—C4—C3i	178.42 (19)
O3—N1—C2—C3	23.8 (3)	O4i—N2—C4—C3i	−1.58 (19)
O2—N1—C2—C1	27.2 (3)	O4—N2—C4—C3	−1.58 (19)
O3—N1—C2—C1	−153.3 (2)	O4i—N2—C4—C3	178.42 (19)

D—H···A	D—H	H···A	D···A	D—H···A
O5—H5B···O2ii	0.91 (2)	2.17 (2)	3.061 (3)	166 (5)
O5—H5A···O1	0.92 (2)	1.93 (2)	2.848 (2)	172 (5)
C3—H3···O3iii	0.93	2.52	3.450 (2)	175

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O5—H5B⋯O2i	0.91 (2)	2.17 (2)	3.061 (3)	166 (5)
O5—H5A⋯O1	0.92 (2)	1.93 (2)	2.848 (2)	172 (5)
C3—H3⋯O3ii	0.93	2.52	3.450 (2)	175

Symmetry codes: (i) ; (ii) .