Ammonium imidazolium dichromate.

In the crystal structure of the title compound, (C(3)H(5)N(2))(NH(4))[Cr(2)O(7)], the anions and cations are linked through N-H⋯O hydrogen bonds, resulting in a three-dimensional structure which contains three kinds of layers parallel to (001). One layer contains imidazole cations, the other two layers the ammonium cations and dichromate anions. The dichromate anion has an eclipsed conformation with a dihedral angle of 14.65 (18)° between the mean planes of the O-P-O-P-O backbone.

Related literature

The title compound was synthesized as part of a search for ferroelectric materials. For general background to ferroelectric compounds with metal-organic framework structures, see: Fu et al. (2009 ▶); Ye et al. (2006 ▶); Zhang et al. (2008 ▶, 2010 ▶). For graph-set motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

(C3H5N2)(NH4)[Cr2O7]

M = 303.13

Monoclinic,

a = 5.6260 (11) Å

b = 8.2749 (17) Å

c = 21.593 (4) Å

β = 91.90 (3)°

V = 1004.7 (3) Å3

Z = 4

Mo Kα radiation

μ = 2.18 mm−1

T = 293 K

0.32 × 0.27 × 0.22 mm

Data collection

Rigaku SCXmini diffractometer

Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ▶) T min = 0.502, T max = 0.618

10091 measured reflections

2297 independent reflections

1907 reflections with I > 2σ(I)

R int = 0.047

Refinement

R[F 2 > 2σ(F 2)] = 0.037

wR(F 2) = 0.085

S = 1.09

2297 reflections

152 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.34 e Å−3

Δρmin = −0.52 e Å−3

Data collection: CrystalClear (Rigaku, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812009506/fj2526sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812009506/fj2526Isup2.hkl

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

(C3H5N2)(NH4)[Cr2O7]	F(000) = 608
Mr = 303.13	Dx = 2.004 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2297 reflections
a = 5.6260 (11) Å	θ = 3.1–27.5°
b = 8.2749 (17) Å	µ = 2.18 mm−1
c = 21.593 (4) Å	T = 293 K
β = 91.90 (3)°	Plane, red
V = 1004.7 (3) Å3	0.32 × 0.27 × 0.22 mm
Z = 4

Rigaku SCXmini diffractometer	2297 independent reflections
Radiation source: fine-focus sealed tube	1907 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.047
CCD Profile fitting scans	θmax = 27.5°, θmin = 3.1°
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	h = −7→7
Tmin = 0.502, Tmax = 0.618	k = −10→10
10091 measured reflections	l = −28→27

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.085	H atoms treated by a mixture of independent and constrained refinement
S = 1.09	w = 1/[σ2(Fo2) + (0.0321P)2 + 0.944P] where P = (Fo2 + 2Fc2)/3
2297 reflections	(Δ/σ)max < 0.001
152 parameters	Δρmax = 0.34 e Å−3
0 restraints	Δρmin = −0.52 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
C1	0.3469 (6)	0.7554 (4)	0.06526 (17)	0.0396 (8)
H1A	0.2345	0.7447	0.0956	0.048*
C2	0.6599 (6)	0.8268 (4)	0.01522 (17)	0.0390 (8)
H2A	0.8034	0.8757	0.0060	0.047*
C3	0.5350 (7)	0.7289 (5)	−0.02122 (18)	0.0473 (9)
H3A	0.5725	0.6965	−0.0610	0.057*
N1	0.5234 (6)	0.7387 (4)	0.24161 (17)	0.0325 (6)
N2	0.5405 (5)	0.8437 (4)	0.06922 (14)	0.0437 (7)
H2B	0.5851	0.9023	0.1004	0.052*
N3	0.3399 (5)	0.6843 (3)	0.01056 (15)	0.0449 (8)
H3B	0.2299	0.6200	−0.0030	0.054*
O1	0.0282 (4)	0.9810 (3)	0.42701 (10)	0.0378 (5)
O2	−0.0350 (5)	1.1228 (3)	0.31828 (11)	0.0422 (6)
O3	0.3641 (4)	0.9650 (3)	0.34399 (12)	0.0429 (6)
O4	−0.0528 (4)	0.7910 (2)	0.32273 (11)	0.0375 (5)
O5	−0.0001 (5)	0.5720 (3)	0.41884 (11)	0.0458 (6)
O6	−0.2197 (4)	0.4834 (3)	0.31508 (12)	0.0425 (6)
O7	0.2496 (4)	0.5232 (3)	0.32071 (11)	0.0415 (6)
Cr1	0.08035 (8)	0.97044 (5)	0.35383 (2)	0.02452 (14)
Cr2	−0.00312 (8)	0.58625 (5)	0.34477 (2)	0.02334 (14)
H1B	0.439 (8)	0.692 (6)	0.264 (2)	0.066 (16)*
H1C	0.644 (9)	0.783 (6)	0.256 (2)	0.081 (18)*
H1D	0.556 (8)	0.677 (6)	0.221 (2)	0.051 (15)*
H1E	0.439 (8)	0.796 (6)	0.226 (2)	0.059 (15)*

	U11	U22	U33	U12	U13	U23
C1	0.0366 (18)	0.0382 (19)	0.044 (2)	−0.0071 (15)	0.0056 (15)	0.0040 (16)
C2	0.0287 (16)	0.0377 (18)	0.051 (2)	−0.0066 (14)	0.0055 (15)	0.0081 (16)
C3	0.051 (2)	0.051 (2)	0.040 (2)	0.0087 (18)	0.0061 (17)	−0.0013 (18)
N1	0.0337 (17)	0.0280 (16)	0.0357 (17)	0.0060 (14)	−0.0008 (14)	0.0038 (14)
N2	0.0505 (18)	0.0362 (16)	0.0438 (18)	−0.0065 (14)	−0.0080 (14)	−0.0024 (13)
N3	0.0370 (16)	0.0365 (16)	0.060 (2)	−0.0108 (13)	−0.0108 (14)	−0.0028 (15)
O1	0.0463 (13)	0.0415 (13)	0.0256 (11)	0.0090 (11)	0.0029 (10)	−0.0019 (10)
O2	0.0659 (16)	0.0254 (11)	0.0352 (13)	0.0112 (11)	0.0000 (11)	0.0048 (10)
O3	0.0323 (12)	0.0482 (14)	0.0485 (15)	−0.0032 (11)	0.0072 (11)	−0.0030 (12)
O4	0.0465 (13)	0.0199 (10)	0.0452 (14)	−0.0002 (9)	−0.0130 (11)	0.0003 (9)
O5	0.0538 (15)	0.0505 (15)	0.0334 (13)	0.0077 (12)	0.0042 (11)	0.0057 (11)
O6	0.0324 (12)	0.0254 (11)	0.0686 (17)	−0.0075 (9)	−0.0132 (11)	0.0037 (11)
O7	0.0290 (12)	0.0459 (14)	0.0501 (15)	0.0066 (10)	0.0109 (11)	0.0050 (11)
Cr1	0.0307 (3)	0.0190 (2)	0.0239 (3)	0.00146 (18)	0.00126 (19)	−0.00066 (18)
Cr2	0.0199 (2)	0.0209 (2)	0.0292 (3)	0.00099 (17)	0.00006 (18)	0.00220 (18)

C1—N2	1.312 (4)	N1—H1E	0.74 (5)
C1—N3	1.319 (5)	N2—H2B	0.8600
C1—H1A	0.9300	N3—H3B	0.8600
C2—C3	1.316 (5)	O1—Cr1	1.619 (2)
C2—N2	1.372 (5)	O2—Cr1	1.602 (2)
C2—H2A	0.9300	O3—Cr1	1.618 (2)
C3—N3	1.364 (5)	O4—Cr2	1.779 (2)
C3—H3A	0.9300	O4—Cr1	1.784 (2)
N1—H1B	0.79 (5)	O5—Cr2	1.603 (2)
N1—H1C	0.83 (5)	O6—Cr2	1.602 (2)
N1—H1D	0.71 (5)	O7—Cr2	1.616 (2)
N2—C1—N3	107.8 (3)	C2—N2—H2B	125.8
N2—C1—H1A	126.1	C1—N3—C3	109.2 (3)
N3—C1—H1A	126.1	C1—N3—H3B	125.4
C3—C2—N2	107.7 (3)	C3—N3—H3B	125.4
C3—C2—H2A	126.1	Cr2—O4—Cr1	129.15 (13)
N2—C2—H2A	126.1	O2—Cr1—O3	110.17 (13)
C2—C3—N3	106.8 (3)	O2—Cr1—O1	109.98 (12)
C2—C3—H3A	126.6	O3—Cr1—O1	109.94 (13)
N3—C3—H3A	126.6	O2—Cr1—O4	108.44 (11)
H1B—N1—H1C	119 (5)	O3—Cr1—O4	109.34 (12)
H1B—N1—H1D	102 (5)	O1—Cr1—O4	108.94 (12)
H1C—N1—H1D	110 (5)	O6—Cr2—O5	110.06 (14)
H1B—N1—H1E	102 (4)	O6—Cr2—O7	111.42 (13)
H1C—N1—H1E	113 (5)	O5—Cr2—O7	108.47 (13)
H1D—N1—H1E	110 (5)	O6—Cr2—O4	106.74 (11)
C1—N2—C2	108.5 (3)	O5—Cr2—O4	109.46 (12)
C1—N2—H2B	125.8	O7—Cr2—O4	110.69 (12)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2B···O7i	0.86	2.16	3.011 (4)	170
N3—H3B···O1ii	0.86	2.04	2.827 (4)	152
N1—H1B···O7	0.79 (5)	2.16 (5)	2.940 (4)	169 (5)
N1—H1C···O4iii	0.83 (5)	2.19 (5)	2.943 (4)	151 (5)
N1—H1D···O3iv	0.71 (5)	2.29 (5)	3.004 (5)	176 (5)
N1—H1E···O6v	0.74 (5)	2.15 (5)	2.895 (4)	174 (5)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2B⋯O7i	0.86	2.16	3.011 (4)	170
N3—H3B⋯O1ii	0.86	2.04	2.827 (4)	152
N1—H1B⋯O7	0.79 (5)	2.16 (5)	2.940 (4)	169 (5)
N1—H1C⋯O4iii	0.83 (5)	2.19 (5)	2.943 (4)	151 (5)
N1—H1D⋯O3iv	0.71 (5)	2.29 (5)	3.004 (5)	176 (5)
N1—H1E⋯O6v	0.74 (5)	2.15 (5)	2.895 (4)	174 (5)

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