Buy article online - an online subscription or single-article purchase is required to access this article.
Download citation
Download citation
link to html
The title compound, C3H3N5O4, consists of three planar fragments twisted in relation to each other, namely a triazole ring, a nitro­methyl­ene group and a nitro group. Molecular conformation analysis shows that the first stage of thermal decomposition is a breakage of the H2C-NO2 bond. There are essential conformational differences in the mol­ecule in comparison with semi-empirical calculations.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S010827010000665X/av1037sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S010827010000665X/av1037Isup2.hkl
Contains datablock I

CCDC reference: 150344

Comment top

Nitro derivatives of 1,2,4-triazole are of interest as highly energetic compounds (Pevzner, 1997). X-ray structure investigation of the compounds is important not only for providing unambiguous confirmation of their molecular structure; since one of the basic characteristics of explosives is their density, it is necessary to know their structure parameters to reveal factors that have an influence on crystal density (Stein, 1981), with the ultimate aim of enabling a computer search of hypothetical high density highly energetic compounds and their subsequent synthesis (Coburn et al., 1986). No less important is that knowledge of the structure parameters of a highly energetic molecule allow the prediction of its reaction ability, in particular its thermal stability (Manelis et al., 1996). Accordingly, the structure of the title compound, (I), was investigated using single-crystal X-ray techniques. \sch

The molecule of (I) (Fig.1) consists of three bonded planar fragments, namely a 1,2,4-triazole ring, a nitromethylene group and a nitro group (H atoms are omitted from the consideration). The triazole cycle is practically planar [r.m.s. deviation 0.0014 (8), maximum deviation 0.002 (8) Å]. The interatomic distances within the cycle are not equal, ranging from 1.304 (2) to 1.355 (2) Å. The nitro group bonded with the triazole ring is located at 17.8 (2)° with respect to the ring plane. The nitromethylene group is strictly planar and is located nearly orthogonal [83.25 (6)°] to the triazole ring, while the torsion angle O3—N8—C7—N1 is 2.8 (2)°. The C—NO2 bond lengths are not equal [1.450 (2) and 1.509 (2) Å]: the greater value relates to the bond in the nitroalkyl fragment of the molecule. On the whole, bond lengths and angles in (I) are close to the corresponding values in other nitro derivatives of 1,2,4-triazole (Closset et al., 1975; Starova et al., 1977; Nikitina et al., 1982).

The structure of (I) has been investigated theoretically by semi-empirical MNDO, AM1 and PM3 methods (please define; Stepanov et al., 2000). In contrast to the experimental data, these calculations show that the location of the nitro group orthogonal to the triazole ring is more preferable. This disagreement might be due to the incorrect evaluation of the resonance effect between the triazole cycle and the nitro group. According to? the semi-empirical calculations, the torsion angle O3—N8—C7—N1 is in the range 44–60°, depending on the calculation method. Calculated C—NO2 bond lengths are somewhat overestimated, with values of 1.482–1.512 and 1.553–1.571 Å for nitro groups bonded to the triazole cycle and the methylene fragment, respectively. However, the X-ray results confirm earlier inference concerning the preference of nitro-group breakage in the nitromethylene part of (I) during thermal decomposition (Stepanov et al., 2000).

In conclusion, we note that the density of (I) (1.76 Mg m−3) exceeds the density of the brutto-formula isomer 1-methyl-3,5-dinitro-1,2,4-triazole (1.63 Mg m−3; Starova et al., 1977). This fact leads to the expectation of an increase in the value of the detonation velocity by 400–500 m s−1 for (I) in comparison with the latter compound. It would be expected that the high density of a crystal composed of organic molecules is associated with short intermolecular distances, but all intermolecular atom-atom distances exceed the corresponding sums of ordinary van der Waals radii in the crystal of (I).

Experimental top

Compound (I) (Stepanov et al., 2000) was obtained by double recrystallization from water (m.p. 453 K with decomposition). Single crystals were obtained by evaporation of a saturated alcohol (which?) solution.

Computing details top

Data collection: KM-4 Software (Kuma, 1991); cell refinement: KM-4 Software; data reduction: KM-4 Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL (Sheldrick, 1995); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The molecule of (I) showing the atom-numbering scheme and with 50% probability displacement ellipsoids. H atoms are drawn as small spheres of arbitrary radii.
3-Nitro-1-nitromethyl-1H-1,2,4-triazole top
Crystal data top
C3H3N5O4F(000) = 352
Mr = 173.10Dx = 1.758 Mg m3
Monoclinic, P21/cCu Kα radiation, λ = 1.54051 Å
a = 6.6305 (4) ÅCell parameters from 25 reflections
b = 9.2888 (3) Åθ = 22–30°
c = 10.9828 (6) ŵ = 1.44 mm1
β = 104.837 (5)°T = 293 K
V = 653.87 (6) Å3Plate, colourless
Z = 40.35 × 0.30 × 0.25 mm
Data collection top
Kuma KM-4 four-circle
diffractometer
Rint = 0.019
Radiation source: fine-focus sealed tubeθmax = 70.0°, θmin = 6.3°
Graphite monochromatorh = 87
profile data from ω/2θ scansk = 1111
2493 measured reflectionsl = 013
1195 independent reflections2 standard reflections every 50 reflections
1015 reflections with I > 2σ(I) intensity decay: none
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.032All H-atom parameters refined
wR(F2) = 0.087Calculated w = 1/[σ2(Fo2) + (0.0492P)2 + 0.1343P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max < 0.001
1195 reflectionsΔρmax = 0.18 e Å3
122 parametersΔρmin = 0.17 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0170 (15)
Crystal data top
C3H3N5O4V = 653.87 (6) Å3
Mr = 173.10Z = 4
Monoclinic, P21/cCu Kα radiation
a = 6.6305 (4) ŵ = 1.44 mm1
b = 9.2888 (3) ÅT = 293 K
c = 10.9828 (6) Å0.35 × 0.30 × 0.25 mm
β = 104.837 (5)°
Data collection top
Kuma KM-4 four-circle
diffractometer
Rint = 0.019
2493 measured reflections2 standard reflections every 50 reflections
1195 independent reflections intensity decay: none
1015 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0320 restraints
wR(F2) = 0.087All H-atom parameters refined
S = 1.03Δρmax = 0.18 e Å3
1195 reflectionsΔρmin = 0.17 e Å3
122 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
N20.01891 (17)0.18566 (12)0.05048 (11)0.0333 (3)
N10.14659 (17)0.15240 (11)0.16441 (11)0.0315 (3)
N40.01845 (19)0.34469 (13)0.19974 (12)0.0432 (3)
O30.48807 (18)0.22243 (13)0.10386 (13)0.0612 (4)
C30.0729 (2)0.29980 (14)0.08001 (13)0.0322 (3)
N80.48470 (18)0.09794 (13)0.13424 (11)0.0391 (3)
N60.22771 (18)0.37542 (13)0.01595 (12)0.0408 (3)
O10.3053 (2)0.31141 (14)0.11321 (12)0.0633 (4)
C70.2991 (2)0.04162 (15)0.17534 (15)0.0361 (3)
O40.62109 (18)0.01055 (14)0.13497 (12)0.0610 (4)
O20.2692 (2)0.49800 (12)0.00697 (13)0.0647 (4)
C50.1219 (2)0.24805 (16)0.25091 (15)0.0410 (4)
H10.352 (2)0.0150 (17)0.2643 (17)0.040 (4)*
H20.249 (2)0.0362 (18)0.1221 (17)0.044 (4)*
H30.198 (3)0.2389 (18)0.3351 (19)0.054 (5)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N20.0333 (6)0.0325 (6)0.0332 (6)0.0001 (4)0.0071 (5)0.0012 (4)
N10.0298 (6)0.0317 (5)0.0323 (6)0.0020 (4)0.0068 (5)0.0002 (4)
N40.0420 (7)0.0447 (7)0.0432 (7)0.0022 (5)0.0113 (6)0.0113 (5)
O30.0474 (7)0.0528 (7)0.0893 (10)0.0006 (5)0.0284 (6)0.0266 (6)
C30.0302 (6)0.0301 (6)0.0374 (7)0.0034 (5)0.0107 (6)0.0007 (5)
N80.0339 (6)0.0460 (7)0.0365 (7)0.0057 (5)0.0075 (5)0.0034 (5)
N60.0392 (6)0.0372 (6)0.0474 (8)0.0030 (5)0.0137 (6)0.0055 (5)
O10.0709 (8)0.0650 (8)0.0438 (7)0.0172 (6)0.0039 (6)0.0025 (6)
C70.0356 (7)0.0302 (6)0.0417 (8)0.0001 (5)0.0083 (6)0.0029 (6)
O40.0487 (7)0.0706 (8)0.0662 (8)0.0238 (6)0.0191 (6)0.0033 (6)
O20.0678 (8)0.0385 (6)0.0856 (10)0.0178 (5)0.0156 (7)0.0051 (6)
C50.0411 (8)0.0471 (8)0.0344 (8)0.0003 (6)0.0088 (7)0.0074 (6)
Geometric parameters (Å, º) top
N2—C31.3043 (17)N8—O41.2138 (15)
N2—N11.3547 (17)N8—C71.5088 (18)
N1—C51.3410 (18)N6—O21.2129 (17)
N1—C71.4261 (17)N6—O11.2157 (17)
N4—C51.311 (2)C7—H10.981 (18)
N4—C31.3380 (18)C7—H20.936 (17)
O3—N81.2053 (16)C5—H30.94 (2)
C3—N61.4503 (19)
C3—N2—N1100.18 (10)O2—N6—C3117.38 (13)
C5—N1—N2110.03 (11)O1—N6—C3117.60 (12)
C5—N1—C7129.12 (13)N1—C7—N8109.86 (11)
N2—N1—C7120.28 (11)N1—C7—H1109.3 (9)
C5—N4—C3101.02 (11)N8—C7—H1106.0 (9)
N2—C3—N4118.16 (12)N1—C7—H2111.8 (10)
N2—C3—N6120.10 (12)N8—C7—H2105.7 (10)
N4—C3—N6121.73 (12)H1—C7—H2114.0 (14)
O3—N8—O4125.23 (13)N4—C5—N1110.60 (14)
O3—N8—C7119.33 (11)N4—C5—H3128.9 (11)
O4—N8—C7115.44 (12)N1—C5—H3120.5 (11)
O2—N6—O1125.03 (14)
C3—N2—N1—C50.34 (14)N4—C3—N6—O1162.62 (13)
C3—N2—N1—C7172.45 (11)C5—N1—C7—N891.94 (16)
N1—N2—C3—N40.39 (15)N2—N1—C7—N878.49 (14)
N1—N2—C3—N6179.72 (11)O3—N8—C7—N12.83 (19)
C5—N4—C3—N20.28 (16)O4—N8—C7—N1177.18 (13)
C5—N4—C3—N6179.59 (12)C3—N4—C5—N10.03 (15)
N2—C3—N6—O2161.68 (13)N2—N1—C5—N40.21 (16)
N4—C3—N6—O217.63 (19)C7—N1—C5—N4171.42 (13)
N2—C3—N6—O118.08 (19)

Experimental details

Crystal data
Chemical formulaC3H3N5O4
Mr173.10
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)6.6305 (4), 9.2888 (3), 10.9828 (6)
β (°) 104.837 (5)
V3)653.87 (6)
Z4
Radiation typeCu Kα
µ (mm1)1.44
Crystal size (mm)0.35 × 0.30 × 0.25
Data collection
DiffractometerKuma KM-4 four-circle
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
2493, 1195, 1015
Rint0.019
(sin θ/λ)max1)0.610
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.032, 0.087, 1.03
No. of reflections1195
No. of parameters122
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.18, 0.17

Computer programs: KM-4 Software (Kuma, 1991), KM-4 Software, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), XP in SHELXTL (Sheldrick, 1995), SHELXL97.

Selected geometric parameters (Å, º) top
N1—C71.4261 (17)N8—C71.5088 (18)
C5—N1—C7—N891.94 (16)N2—N1—C7—N878.49 (14)
 

Subscribe to Acta Crystallographica Section C: Structural Chemistry

The full text of this article is available to subscribers to the journal.

If you have already registered and are using a computer listed in your registration details, please email support@iucr.org for assistance.

Buy online

You may purchase this article in PDF and/or HTML formats. For purchasers in the European Community who do not have a VAT number, VAT will be added at the local rate. Payments to the IUCr are handled by WorldPay, who will accept payment by credit card in several currencies. To purchase the article, please complete the form below (fields marked * are required), and then click on `Continue'.
E-mail address* 
Repeat e-mail address* 
(for error checking) 

Format*   PDF (US $40)
   HTML (US $40)
   PDF+HTML (US $50)
In order for VAT to be shown for your country javascript needs to be enabled.

VAT number 
(non-UK EC countries only) 
Country* 
 

Terms and conditions of use
Contact us

Follow Acta Cryst. C
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds