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The title compound, C4H4N6O5, crystallizes in the monoclinic space group P21/n, and is an energetic compound containing only C, H, N, and O with a density of 1.919 Mg m-3. Among other reasons, this remarkably high density is attributed to an extensive system of intra- and intermolecular hydrogen bonds which results in a packing scheme involving zigzag sheets.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801010352/cf6082sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801010352/cf6082Isup2.hkl
Contains datablock I

CCDC reference: 170788

Key indicators

  • Single-crystal X-ray study
  • T = 294 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.040
  • wR factor = 0.097
  • Data-to-parameter ratio = 11.3

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry








Comment top

The title compound, 2,6-diamino-3,5-dinitro-1,4-pyrazine 1-oxide (ANPZO), (I), is a very stable and relatively insensitive energetic material with a very high density of 1.919 Mg m-3. Every H atom is involved in intramolecular hydrogen-bonding interactions to its neighboring oxygen atom as well as participating in intermolecular interactions with adjoining molecules. Thus, it is related to other similar compounds, such as 1,3,5-triamino-2,4,6-trinitrobenzene (TATB; Cady & Larson, 1965; Kolb & Rizzo, 1979) and 2,6-diamino-3,5,-dinitropyrazine (ANPZ; Gilardi & George, 1984), which have a similar extensive system of intra- and intermolecular hydrogen-bonding interactions resulting in a sheet-like packing system, high densities (1.937 and 1.812 Mg m-3, respectively), and relative insensitivity. These intermolecular hydrogen-bonding interactions result in ruffled parallel sheets in the [101] direction. One of the potentially useful features of ANPZO is its relative insensitivity. Sensitivity is often tested via the drop-height method, i.e. the height of the drop of a steel ball required to detonate the compound, with large values reflecting insensitivity. In such testing, the parent molecule, ANPZ (2,6-diamino-3,5-dinitro-1,4-pyrazine), has values which are so large they cannot be accurately measured, while ANPZO has a value of 117 cm (Pagoria, 2001). These values indicate that ANPZO is safer compared to other commonly used energetic compounds such as trinitrotoluene (80 cm) and HMX (32 cm). Fig. 1 shows the structure and labeling scheme for the title compound. Hydrogen-bonding metrical parameters are given in Table 1.

Experimental top

Crystals of the title compound were supplied by Dr Philip Pagoria, Energetic Materials Laboratory, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. Crystal and reflection data were obtained using standard procedures (Butcher et al., 1995).

Computing details top

Data collection: XSCANS (Bruker, 1994); cell refinement: XSCANS; data reduction: SHELXTL (Sheldrick, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. View of 2,6-diamino-3,5-dinitro-1,4-pyrazine 1-oxide showing the labeling of all non-H atoms. Displacement ellipsoids are at the 20% probability level. H atoms are drawn as small circles of arbitrary radii.
[Figure 2] Fig. 2. Packing diagram of 2,6-diamino-3,5-dinitro-1,4-pyrazine 1-oxide, viewed down the [101] direction.
2,6-diamino-3,5-dinitro-1,4-pyrazine-1-oxide top
Crystal data top
C4H4N6O5F(000) = 440
Mr = 216.13Dx = 1.919 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 5.7159 (8) ÅCell parameters from 58 reflections
b = 15.8498 (14) Åθ = 2.8–18.3°
c = 8.4139 (7) ŵ = 0.18 mm1
β = 101.041 (7)°T = 294 K
V = 748.16 (14) Å3Chunky prism, yellow
Z = 40.4 × 0.3 × 0.25 mm
Data collection top
Bruker P4
diffractometer
1185 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.015
Graphite monochromatorθmax = 27.5°, θmin = 2.6°
2θ/ω scansh = 07
Absorption correction: integration
(Wuensch & Prewitt, 1965)
k = 2018
Tmin = 0.990, Tmax = 0.993l = 1010
3771 measured reflections3 standard reflections every 97 reflections
1716 independent reflections intensity decay: 1.0%
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.097H atoms treated by a mixture of independent and constrained refinement
S = 1.01 w = 1/[σ2(Fo2) + (0.041P)2 + 0.0834P]
where P = (Fo2 + 2Fc2)/3
1716 reflections(Δ/σ)max < 0.001
152 parametersΔρmax = 0.23 e Å3
0 restraintsΔρmin = 0.21 e Å3
Crystal data top
C4H4N6O5V = 748.16 (14) Å3
Mr = 216.13Z = 4
Monoclinic, P21/nMo Kα radiation
a = 5.7159 (8) ŵ = 0.18 mm1
b = 15.8498 (14) ÅT = 294 K
c = 8.4139 (7) Å0.4 × 0.3 × 0.25 mm
β = 101.041 (7)°
Data collection top
Bruker P4
diffractometer
1185 reflections with I > 2σ(I)
Absorption correction: integration
(Wuensch & Prewitt, 1965)
Rint = 0.015
Tmin = 0.990, Tmax = 0.9933 standard reflections every 97 reflections
3771 measured reflections intensity decay: 1.0%
1716 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0400 restraints
wR(F2) = 0.097H atoms treated by a mixture of independent and constrained refinement
S = 1.01Δρmax = 0.23 e Å3
1716 reflectionsΔρmin = 0.21 e Å3
152 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.1565 (3)0.90540 (9)0.47096 (18)0.0240 (4)
O10.3630 (2)0.93827 (9)0.40265 (17)0.0348 (4)
C20.0702 (3)0.92079 (11)0.6322 (2)0.0228 (4)
N20.2081 (3)0.96805 (11)0.7048 (2)0.0305 (4)
H2A0.344 (4)0.9849 (15)0.639 (3)0.050 (7)*
H2B0.159 (4)0.9802 (16)0.814 (3)0.060 (8)*
C30.1558 (3)0.88493 (11)0.6943 (2)0.0233 (4)
N30.2748 (3)0.89943 (10)0.86104 (19)0.0280 (4)
O3A0.1754 (3)0.94651 (10)0.94385 (17)0.0434 (4)
O3B0.4660 (3)0.86564 (10)0.91133 (17)0.0409 (4)
N40.2750 (3)0.83913 (9)0.60789 (18)0.0236 (4)
C50.1862 (3)0.82688 (11)0.4549 (2)0.0226 (4)
N50.3341 (3)0.77874 (10)0.36491 (18)0.0275 (4)
O5A0.2944 (3)0.78509 (11)0.21769 (16)0.0444 (4)
O5B0.4921 (3)0.73514 (10)0.43965 (17)0.0450 (4)
C60.0360 (3)0.85960 (11)0.3750 (2)0.0225 (4)
N60.1406 (3)0.85208 (11)0.2225 (2)0.0305 (4)
H6A0.069 (4)0.8211 (15)0.153 (3)0.044 (7)*
H6B0.286 (4)0.8754 (15)0.191 (3)0.046 (7)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0202 (8)0.0256 (8)0.0256 (8)0.0026 (7)0.0024 (7)0.0005 (6)
O10.0251 (7)0.0416 (9)0.0351 (8)0.0122 (6)0.0010 (6)0.0029 (6)
C20.0257 (9)0.0213 (9)0.0219 (9)0.0041 (8)0.0059 (8)0.0000 (7)
N20.0286 (9)0.0364 (10)0.0269 (9)0.0051 (8)0.0064 (8)0.0052 (7)
C30.0251 (9)0.0247 (10)0.0201 (9)0.0012 (8)0.0045 (8)0.0008 (7)
N30.0299 (9)0.0316 (9)0.0227 (8)0.0030 (7)0.0053 (7)0.0002 (7)
O3A0.0543 (10)0.0470 (10)0.0282 (8)0.0096 (8)0.0059 (7)0.0114 (7)
O3B0.0291 (8)0.0611 (11)0.0293 (8)0.0084 (8)0.0023 (6)0.0012 (7)
N40.0241 (8)0.0240 (8)0.0226 (8)0.0009 (7)0.0045 (6)0.0022 (6)
C50.0229 (9)0.0232 (9)0.0219 (9)0.0019 (8)0.0050 (7)0.0011 (7)
N50.0244 (8)0.0335 (9)0.0247 (8)0.0037 (7)0.0051 (7)0.0001 (7)
O5A0.0388 (9)0.0725 (12)0.0208 (7)0.0162 (8)0.0034 (6)0.0040 (7)
O5B0.0467 (9)0.0582 (10)0.0314 (8)0.0310 (8)0.0104 (7)0.0081 (7)
C60.0233 (9)0.0218 (9)0.0228 (9)0.0009 (8)0.0048 (7)0.0005 (7)
N60.0267 (9)0.0379 (10)0.0249 (9)0.0055 (8)0.0000 (7)0.0047 (7)
Geometric parameters (Å, º) top
N1—O11.3172 (19)N3—O3A1.231 (2)
N1—C61.366 (2)N4—C51.305 (2)
N1—C21.374 (2)C5—C61.417 (3)
C2—N21.319 (2)C5—N51.454 (2)
C2—C31.417 (3)N5—O5B1.213 (2)
N2—H2A0.90 (2)N5—O5A1.2199 (19)
N2—H2B0.93 (3)C6—N61.313 (2)
C3—N41.307 (2)N6—H6A0.91 (2)
C3—N31.455 (2)N6—H6B0.90 (2)
N3—O3B1.218 (2)
O1—N1—C6117.61 (15)O3A—N3—C3117.41 (16)
O1—N1—C2118.88 (15)C5—N4—C3119.05 (16)
C6—N1—C2123.48 (15)N4—C5—C6123.90 (17)
N2—C2—N1115.16 (17)N4—C5—N5115.89 (15)
N2—C2—C3129.84 (17)C6—C5—N5120.18 (15)
N1—C2—C3114.99 (16)O5B—N5—O5A123.27 (17)
C2—N2—H2A113.7 (15)O5B—N5—C5118.57 (15)
C2—N2—H2B118.8 (16)O5A—N5—C5118.15 (15)
H2A—N2—H2B128 (2)N6—C6—N1116.05 (17)
N4—C3—C2123.59 (17)N6—C6—C5129.00 (18)
N4—C3—N3115.28 (16)N1—C6—C5114.96 (16)
C2—C3—N3121.11 (16)C6—N6—H6A119.7 (14)
O3B—N3—O3A123.39 (17)C6—N6—H6B118.1 (15)
O3B—N3—C3119.20 (16)H6A—N6—H6B122 (2)
O1—N1—C2—N20.4 (2)C3—N4—C5—C60.8 (3)
C6—N1—C2—N2178.30 (17)C3—N4—C5—N5177.14 (16)
O1—N1—C2—C3178.31 (15)N4—C5—N5—O5B19.2 (3)
C6—N1—C2—C30.4 (2)C6—C5—N5—O5B162.75 (18)
N2—C2—C3—N4179.66 (19)N4—C5—N5—O5A159.94 (17)
N1—C2—C3—N41.2 (3)C6—C5—N5—O5A18.1 (3)
N2—C2—C3—N31.5 (3)O1—N1—C6—N60.7 (2)
N1—C2—C3—N3176.96 (15)C2—N1—C6—N6178.62 (17)
N4—C3—N3—O3B3.7 (3)O1—N1—C6—C5179.17 (15)
C2—C3—N3—O3B177.99 (17)C2—N1—C6—C51.2 (2)
N4—C3—N3—O3A175.65 (17)N4—C5—C6—N6179.17 (18)
C2—C3—N3—O3A2.6 (3)N5—C5—C6—N61.3 (3)
C2—C3—N4—C51.8 (3)N4—C5—C6—N10.7 (3)
N3—C3—N4—C5176.47 (16)N5—C5—C6—N1178.52 (15)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···O1i0.90 (2)2.05 (2)2.861 (2)149 (2)
N2—H2A···O10.90 (2)2.10 (2)2.571 (2)111.2 (18)
N2—H2B···O3A0.93 (3)2.08 (3)2.697 (2)123 (2)
N2—H2B···O3Aii0.93 (3)2.36 (3)3.224 (2)154 (2)
N6—H6A···O5Biii0.91 (2)2.10 (2)2.974 (2)160 (2)
N6—H6A···O5A0.91 (2)2.12 (2)2.711 (2)121.1 (18)
N6—H6A···N4iii0.91 (2)2.69 (2)3.189 (2)114.9 (18)
N6—H6B···O3Biv0.90 (2)2.51 (2)3.115 (2)125.0 (19)
Symmetry codes: (i) x1, y+2, z+1; (ii) x, y+2, z+2; (iii) x1/2, y+3/2, z1/2; (iv) x1, y, z1.

Experimental details

Crystal data
Chemical formulaC4H4N6O5
Mr216.13
Crystal system, space groupMonoclinic, P21/n
Temperature (K)294
a, b, c (Å)5.7159 (8), 15.8498 (14), 8.4139 (7)
β (°) 101.041 (7)
V3)748.16 (14)
Z4
Radiation typeMo Kα
µ (mm1)0.18
Crystal size (mm)0.4 × 0.3 × 0.25
Data collection
DiffractometerBruker P4
diffractometer
Absorption correctionIntegration
(Wuensch & Prewitt, 1965)
Tmin, Tmax0.990, 0.993
No. of measured, independent and
observed [I > 2σ(I)] reflections
3771, 1716, 1185
Rint0.015
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.040, 0.097, 1.01
No. of reflections1716
No. of parameters152
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.23, 0.21

Computer programs: XSCANS (Bruker, 1994), XSCANS, SHELXTL (Sheldrick, 1997), SHELXS97 (Sheldrick, 1990), SHELXTL.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···O1i0.90 (2)2.05 (2)2.861 (2)149 (2)
N2—H2A···O10.90 (2)2.10 (2)2.571 (2)111.2 (18)
N2—H2B···O3A0.93 (3)2.08 (3)2.697 (2)123 (2)
N2—H2B···O3Aii0.93 (3)2.36 (3)3.224 (2)154 (2)
N6—H6A···O5Biii0.91 (2)2.10 (2)2.974 (2)160 (2)
N6—H6A···O5A0.91 (2)2.12 (2)2.711 (2)121.1 (18)
N6—H6A···N4iii0.91 (2)2.69 (2)3.189 (2)114.9 (18)
N6—H6B···O3Biv0.90 (2)2.51 (2)3.115 (2)125.0 (19)
Symmetry codes: (i) x1, y+2, z+1; (ii) x, y+2, z+2; (iii) x1/2, y+3/2, z1/2; (iv) x1, y, z1.
 

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