5-Amino-1H-1,2,4-triazol-4-ium-3-carboxyl-ate hemihydrate.

The asymmetric unit of the title compound, C(3)H(4)N(4)O(2)·0.5H(2)O, comprises two whole mol-ecules of 5-amino-1H-1,2,4-triazole-3-carb-oxy-lic acid in its zwitterionic form (proton transfer occurs from the carb-oxy-lic acid group to the N hetero-atom at position 1), plus one water mol-ecule of crystallization. The organic moieties are disposed into supra-molecular layers linked by N-H⋯O and N-H⋯N hydrogen bonds parallel to the bc plane. Additional O-H⋯O and N-H⋯O hydrogen bonds involving the water mol-ecules and the organic mol-ecules lead to the formation of double-deck supra-molecular arrangements which are inter-connected along the a axis via π-π stacking [centroid-centroid distance = 3.507 (3) Å].

Related literature

For related compounds with 5-amino-1H-1,2,4-triazole-3-carb­oxy­lic acid residues, see: Masiukiewicz et al. (2007 ▶); Ouakkaf et al. (2011 ▶); Sun et al. (2011 ▶); Wawrzycka-Gorczyca et al. (2003 ▶). For previous work in crystal engineering, see: Amarante, Gonçalves et al. (2009 ▶); Amarante, Figueiredo et al. (2009 ▶); Shi et al. (2008 ▶); Paz & Klinowski (2004 ▶, 2007 ▶); Paz et al. (2005 ▶). For graph-set notation, see: Grell et al. (1999 ▶). For a description of the Cambridge Structural Database, see: Allen (2002 ▶).

Experimental

Crystal data

C3H4N4O2·0.5H2O

M = 137.11

Triclinic,

a = 6.5440 (11) Å

b = 6.9490 (8) Å

c = 12.0723 (17) Å

α = 93.976 (7)°

β = 105.012 (9)°

γ = 99.703 (8)°

V = 518.96 (13) Å3

Z = 4

Mo Kα radiation

μ = 0.15 mm−1

T = 150 K

0.10 × 0.07 × 0.04 mm

Data collection

Bruker X8 KappaCCD APEXII diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 1997 ▶) T min = 0.985, T max = 0.994

4474 measured reflections

1797 independent reflections

1433 reflections with I > 2σ(I)

R int = 0.032

Refinement

R[F 2 > 2σ(F 2)] = 0.066

wR(F 2) = 0.202

S = 1.24

1797 reflections

202 parameters

13 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.42 e Å−3

Δρmin = −0.46 e Å−3

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT-Plus (Bruker, 2005 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: DIAMOND (Brandenburg, 2009 ▶); software used to prepare material for publication: SHELXTL.

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S160053681102811X/tk2764sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681102811X/tk2764Isup2.hkl

Supplementary material file. DOI: 10.1107/S160053681102811X/tk2764Isup3.cml

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

C3H4N4O2·0.5H2O	Z = 4
Mr = 137.11	F(000) = 284
Triclinic, P1	Dx = 1.755 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.5440 (11) Å	Cell parameters from 2284 reflections
b = 6.9490 (8) Å	θ = 3.0–26.5°
c = 12.0723 (17) Å	µ = 0.15 mm−1
α = 93.976 (7)°	T = 150 K
β = 105.012 (9)°	Block, colourless
γ = 99.703 (8)°	0.10 × 0.07 × 0.04 mm
V = 518.96 (13) Å3

Bruker X8 KappaCCD APEXII diffractometer	1797 independent reflections
Radiation source: fine-focus sealed tube	1433 reflections with I > 2σ(I)
graphite	Rint = 0.032
ω and φ scans	θmax = 25.3°, θmin = 3.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1997)	h = −7→7
Tmin = 0.985, Tmax = 0.994	k = −8→8
4474 measured reflections	l = −14→14

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)] = 0.066	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.202	H atoms treated by a mixture of independent and constrained refinement
S = 1.24	w = 1/[σ2(Fo2) + (0.053P)2 + 2.637P] where P = (Fo2 + 2Fc2)/3
1797 reflections	(Δ/σ)max < 0.001
202 parameters	Δρmax = 0.42 e Å−3
13 restraints	Δρmin = −0.46 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
O1	0.2627 (6)	0.4287 (5)	1.1942 (3)	0.0210 (8)
O2	0.2494 (6)	0.6539 (5)	1.0686 (3)	0.0204 (8)
C1	0.2566 (8)	0.4869 (7)	1.0970 (4)	0.0181 (11)
C2	0.2597 (8)	0.3319 (7)	1.0033 (4)	0.0145 (10)
C3	0.2551 (8)	0.2009 (7)	0.8332 (4)	0.0151 (10)
N1	0.2483 (7)	0.3692 (6)	0.8926 (3)	0.0156 (9)
H1	0.230 (9)	0.492 (4)	0.867 (5)	0.023*
N2	0.2760 (7)	0.1506 (6)	1.0170 (3)	0.0190 (10)
N3	0.2736 (7)	0.0699 (6)	0.9090 (3)	0.0180 (9)
H3	0.262 (9)	−0.066 (2)	0.887 (5)	0.027*
N4	0.2452 (7)	0.1709 (6)	0.7223 (3)	0.0185 (10)
H4A	0.234 (9)	0.266 (5)	0.670 (3)	0.028*
H4B	0.251 (9)	0.049 (3)	0.685 (3)	0.028*
O3	0.2553 (6)	0.3765 (5)	0.4390 (3)	0.0227 (9)
O4	0.2348 (6)	0.5057 (5)	0.6096 (3)	0.0219 (9)
C4	0.2476 (8)	0.5132 (7)	0.5087 (4)	0.0151 (10)
C5	0.2534 (8)	0.7084 (7)	0.4618 (4)	0.0146 (10)
C6	0.2720 (8)	0.9152 (7)	0.3368 (4)	0.0146 (10)
N5	0.2730 (7)	0.7267 (6)	0.3525 (3)	0.0149 (9)
H5	0.272 (9)	0.622 (5)	0.298 (4)	0.022*
N6	0.2409 (7)	0.8740 (6)	0.5147 (3)	0.0167 (9)
N7	0.2527 (7)	1.0044 (6)	0.4344 (3)	0.0157 (9)
H7	0.248 (9)	1.139 (3)	0.452 (5)	0.024*
N8	0.2862 (8)	0.9965 (6)	0.2414 (4)	0.0232 (10)
H8A	0.274 (10)	0.918 (6)	0.172 (2)	0.035*
H8B	0.276 (10)	1.127 (3)	0.228 (4)	0.035*
O1W	0.1593 (6)	0.7013 (5)	0.7849 (3)	0.0225 (9)
H1X	0.009 (2)	0.672 (8)	0.775 (4)	0.034*
H1Y	0.194 (7)	0.645 (8)	0.720 (3)	0.034*

	U11	U22	U33	U12	U13	U23
O1	0.036 (2)	0.0223 (19)	0.0072 (17)	0.0083 (16)	0.0077 (15)	0.0024 (14)
O2	0.030 (2)	0.0150 (18)	0.0164 (18)	0.0058 (15)	0.0074 (16)	0.0005 (14)
C1	0.016 (3)	0.018 (3)	0.020 (3)	0.004 (2)	0.005 (2)	−0.002 (2)
C2	0.018 (3)	0.016 (2)	0.010 (2)	0.004 (2)	0.0032 (19)	0.0037 (19)
C3	0.016 (3)	0.014 (2)	0.014 (2)	0.004 (2)	0.002 (2)	0.0019 (19)
N1	0.023 (2)	0.0101 (19)	0.015 (2)	0.0050 (17)	0.0064 (17)	0.0020 (16)
N2	0.029 (2)	0.019 (2)	0.009 (2)	0.0048 (19)	0.0049 (18)	0.0018 (17)
N3	0.030 (2)	0.013 (2)	0.012 (2)	0.0046 (18)	0.0065 (18)	0.0002 (17)
N4	0.035 (3)	0.015 (2)	0.009 (2)	0.0097 (19)	0.0079 (19)	0.0047 (17)
O3	0.040 (2)	0.0126 (17)	0.0193 (19)	0.0071 (16)	0.0121 (17)	0.0045 (15)
O4	0.037 (2)	0.0174 (18)	0.0149 (19)	0.0090 (16)	0.0099 (16)	0.0077 (14)
C4	0.022 (3)	0.013 (2)	0.011 (3)	0.005 (2)	0.005 (2)	0.0067 (19)
C5	0.018 (3)	0.014 (2)	0.012 (2)	0.004 (2)	0.006 (2)	0.0017 (19)
C6	0.018 (2)	0.013 (2)	0.014 (2)	0.005 (2)	0.004 (2)	0.0044 (19)
N5	0.025 (2)	0.011 (2)	0.011 (2)	0.0052 (17)	0.0065 (17)	0.0043 (16)
N6	0.023 (2)	0.015 (2)	0.013 (2)	0.0035 (17)	0.0045 (18)	0.0066 (17)
N7	0.024 (2)	0.0088 (19)	0.015 (2)	0.0058 (17)	0.0059 (18)	0.0024 (16)
N8	0.038 (3)	0.018 (2)	0.017 (2)	0.009 (2)	0.011 (2)	0.0064 (18)
O1W	0.033 (2)	0.0174 (18)	0.0194 (19)	0.0064 (16)	0.0098 (16)	−0.0001 (15)

O1—C1	1.260 (6)	O4—C4	1.246 (6)
O2—C1	1.238 (6)	C4—C5	1.504 (6)
C1—C2	1.513 (7)	C5—N6	1.302 (6)
C2—N2	1.300 (6)	C5—N5	1.370 (6)
C2—N1	1.364 (6)	C6—N8	1.335 (6)
C3—N4	1.324 (6)	C6—N5	1.337 (6)
C3—N3	1.332 (6)	C6—N7	1.339 (6)
C3—N1	1.343 (6)	N5—H5	0.947 (10)
N1—H1	0.946 (11)	N6—N7	1.380 (5)
N2—N3	1.378 (6)	N7—H7	0.948 (10)
N3—H3	0.947 (11)	N8—H8A	0.944 (10)
N4—H4A	0.943 (10)	N8—H8B	0.944 (10)
N4—H4B	0.944 (10)	O1W—H1X	0.946 (10)
O3—C4	1.241 (6)	O1W—H1Y	0.945 (10)
O2—C1—O1	128.4 (4)	O3—C4—C5	114.0 (4)
O2—C1—C2	116.0 (4)	O4—C4—C5	118.2 (4)
O1—C1—C2	115.5 (4)	N6—C5—N5	112.4 (4)
N2—C2—N1	111.7 (4)	N6—C5—C4	126.8 (4)
N2—C2—C1	125.4 (4)	N5—C5—C4	120.8 (4)
N1—C2—C1	122.9 (4)	N8—C6—N5	126.1 (4)
N4—C3—N3	127.0 (5)	N8—C6—N7	127.1 (4)
N4—C3—N1	127.2 (4)	N5—C6—N7	106.7 (4)
N3—C3—N1	105.8 (4)	C6—N5—C5	106.3 (4)
C3—N1—C2	107.2 (4)	C6—N5—H5	128 (3)
C3—N1—H1	130 (3)	C5—N5—H5	126 (3)
C2—N1—H1	123 (3)	C5—N6—N7	103.5 (4)
C2—N2—N3	103.7 (4)	C6—N7—N6	111.1 (4)
C3—N3—N2	111.6 (4)	C6—N7—H7	128 (3)
C3—N3—H3	123 (3)	N6—N7—H7	121 (3)
N2—N3—H3	125 (3)	C6—N8—H8A	121 (3)
C3—N4—H4A	126 (3)	C6—N8—H8B	127 (3)
C3—N4—H4B	123 (3)	H8A—N8—H8B	111 (4)
H4A—N4—H4B	110.9 (16)	H1X—O1W—H1Y	111 (4)
O3—C4—O4	127.8 (4)
O2—C1—C2—N2	177.0 (5)	O3—C4—C5—N6	177.7 (5)
O1—C1—C2—N2	−2.7 (7)	O4—C4—C5—N6	−1.9 (8)
O2—C1—C2—N1	−2.0 (7)	O3—C4—C5—N5	−2.0 (7)
O1—C1—C2—N1	178.2 (5)	O4—C4—C5—N5	178.3 (5)
N4—C3—N1—C2	179.0 (5)	N8—C6—N5—C5	−179.5 (5)
N3—C3—N1—C2	−1.0 (5)	N7—C6—N5—C5	0.1 (5)
N2—C2—N1—C3	0.8 (6)	N6—C5—N5—C6	−0.1 (6)
C1—C2—N1—C3	180.0 (4)	C4—C5—N5—C6	179.7 (4)
N1—C2—N2—N3	−0.3 (6)	N5—C5—N6—N7	0.1 (5)
C1—C2—N2—N3	−179.5 (5)	C4—C5—N6—N7	−179.7 (5)
N4—C3—N3—N2	−179.1 (5)	N8—C6—N7—N6	179.6 (5)
N1—C3—N3—N2	0.8 (6)	N5—C6—N7—N6	0.0 (5)
C2—N2—N3—C3	−0.3 (6)	C5—N6—N7—C6	−0.1 (5)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1W	0.95 (1)	1.87 (2)	2.799 (5)	167 (5)
N3—H3···O1Wi	0.95 (1)	1.87 (3)	2.758 (5)	154 (5)
N4—H4A···O4	0.94 (1)	1.86 (2)	2.777 (5)	163 (4)
N4—H4B···N6i	0.94 (1)	2.29 (3)	3.125 (6)	146 (4)
N5—H5···O1ii	0.95 (1)	1.75 (1)	2.699 (5)	178 (5)
N7—H7···O3iii	0.95 (1)	1.66 (2)	2.579 (5)	161 (5)
N8—H8A···O2ii	0.94 (1)	2.10 (2)	2.989 (5)	155 (4)
N8—H8B···O1iv	0.94 (1)	2.17 (1)	3.117 (5)	178 (5)
O1W—H1X···O1v	0.95 (1)	1.94 (2)	2.839 (5)	159 (5)
O1W—H1Y···O4	0.95 (1)	1.70 (2)	2.634 (5)	170 (5)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1W	0.95 (1)	1.87 (2)	2.799 (5)	167 (5)
N3—H3⋯O1Wi	0.95 (1)	1.87 (3)	2.758 (5)	154 (5)
N4—H4A⋯O4	0.94 (1)	1.86 (2)	2.777 (5)	163 (4)
N4—H4B⋯N6i	0.94 (1)	2.29 (3)	3.125 (6)	146 (4)
N5—H5⋯O1ii	0.95 (1)	1.75 (1)	2.699 (5)	178 (5)
N7—H7⋯O3iii	0.95 (1)	1.66 (2)	2.579 (5)	161 (5)
N8—H8A⋯O2ii	0.94 (1)	2.10 (2)	2.989 (5)	155 (4)
N8—H8B⋯O1iv	0.94 (1)	2.17 (1)	3.117 (5)	178 (5)
O1W—H1X⋯O1v	0.95 (1)	1.94 (2)	2.839 (5)	159 (5)
O1W—H1Y⋯O4	0.95 (1)	1.70 (2)	2.634 (5)	170 (5)

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