Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807026451/nc2037sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807026451/nc2037Isup2.hkl |
CCDC reference: 654873
Key indicators
- Single-crystal X-ray study
- T = 100 K
- Mean (N-C) = 0.003 Å
- R factor = 0.028
- wR factor = 0.054
- Data-to-parameter ratio = 7.7
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT089_ALERT_3_C Poor Data / Parameter Ratio (Zmax .LT. 18) ..... 7.74 PLAT230_ALERT_2_C Hirshfeld Test Diff for O8 - N9 .. 6.51 su PLAT352_ALERT_3_C Short N-H Bond (0.87A) N8 - H10 ... 0.74 Ang. PLAT352_ALERT_3_C Short N-H Bond (0.87A) N2 - H2A ... 0.74 Ang. PLAT480_ALERT_4_C Long H...A H-Bond Reported H2B .. O3 .. 2.63 Ang.
Alert level G REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is correct. If it is not, please give the correct count in the _publ_section_exptl_refinement section of the submitted CIF. From the CIF: _diffrn_reflns_theta_max 29.99 From the CIF: _reflns_number_total 1586 Count of symmetry unique reflns 1592 Completeness (_total/calc) 99.62% TEST3: Check Friedels for noncentro structure Estimate of Friedel pairs measured 0 Fraction of Friedel pairs measured 0.000 Are heavy atom types Z>Si present no PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints ....... 2
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 5 ALERT level C = Check and explain 2 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 1 ALERT type 2 Indicator that the structure model may be wrong or deficient 4 ALERT type 3 Indicator that the structure quality may be low 2 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
checkCIF publication errors
Alert level A PUBL024_ALERT_1_A The number of authors is greater than 5. Please specify the role of each of the co-authors for your paper.
Author Response: General: None of the coauthors has formal training as a crystallographer, therefore the efforts of many individuals were required to arrive at a satisfactory solution and to meaningfully discuss the result. Steinhauser: Synthesis, principal author of the paper, discussion of the molecular aspects of the solution. Crawford: Guidance concerning experimental setup and synthesis including isolation of the crystals. Darwich: Extensive discussion concerning interionic interactions, graph-set analysis of H-bonding, editor of the text. Klapoetke: Head of the department, financial funding, final proof-reading of the paper. Miro Sabate: Author of the figures, discussion concerning literature data and H-bonding, discussion of solution and refinement as well as appropriateness of the chosen space group. Welch: Solution and refinement of the structure, discussion of the structural parameters and appropriateness of the solution. |
1 ALERT level A = Data missing that is essential or data in wrong format 0 ALERT level G = General alerts. Data that may be required is missing
For related literature and structures, see: Bryden et al. (1956); Haas et al. (1965); Hiskey et al. (2005); Katrusiak & Szafrański (1994, 1996); Pace & Flippen-Anderson (1984).
For related literature, see: Bernstein et al. (1995); Jeffrey (1997).
NGN-GN formed in a side reaction using 4.00 g (17 mmol) copper(II) nitrate pentahemihydrate, 6.30 g GN (52 mmol) and 4.5 ml of concentrated HNO3 at 373 K. Single crystals of the compound were obtained upon evaporation of HNO3.
Because no strong anomalously scattering atoms are present the absolute structure cannot be determined and therefore, Friedel opposites were merged in the refinement.
H atoms were located in Fourier difference maps and their coordinates were refined with Uiso fixed at 0.03 Å.
Guanidinium and nitroguanidinium compounds are objects of investigation for a possible application as energetic materials (e.g., Hiskey et al., 2005; Pace & Flippen-Anderson, 1984). The crystal structures of guanidinium nitrate (GN) (Katrusiak & Szafrański, 1994, 1996) and nitroguanidinium nitrate (NGN) (Pace & Flippen-Anderson, 1984) have been determined previously. Here, we report the structure of a new nitroguanidinium nitrate-guanidinium nitrate (NGN-GN) double salt.
As for every potential energetic material, a high density is desired. The density of NGN-GN – 1.757 g.cm-3 (100 K) – is comparable to that of NGN (1.80 g.cm-3; Pace & Flippen-Anderson, 1984), and significantly higher than that of the three phases of GN (GN1, GN2 and GN3). The respective densities are for GN1: 1.458 g.cm-3 (153 K), 1.443 g.cm-3 (185 K), 1.421 g.cm-3 (257 K), 1.410 g.cm-3 (291 K), for GN2: 1.444 g.cm-3 (292 K), and for GN3: 1.400 (391 K) (Katrusiak & Szafrański, 1996).
NGN-GN contains one guanidinium and one nitroguanidinium ion and two nitrate counter-ions. The compound consists of alternating, perpendicular layers of guanidinium and nitroguanidinium cations.
The bond lengths in the guanidinium ion are similar to those found in guanidinium chloride (Haas et al., 1965). The geometry of the nitroguanidinium ion is similar to that in Bryden et al. (1956) and Pace & Flippen-Anderson (1984).
H-bonds in NGN-GN are medium to weak according to Jeffrey (1997). The only ring pattern observed is R2,2(8), and a variety of chain patterns are also observed: C2,2(6), C2,2(8) and C1,2(6) (Bernstein et al., 1995). An intramolecular H-bond is also present (N8–H10···O7).
For related literature and structures, see: Bryden et al. (1956); Haas et al. (1965); Hiskey et al. (2005); Katrusiak & Szafrański (1994, 1996); Pace & Flippen-Anderson (1984).
For related literature, see: Bernstein et al. (1995); Jeffrey (1997).
Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg & Putz, 2005) and ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 and ORTEP-3.
CH5N4O2+·CH6N3+·2NO3− | Z = 4 |
Mr = 289.17 | F(000) = 600 |
Monoclinic, Cc | Dx = 1.756 Mg m−3 |
Hall symbol: C -2yc | Mo Kα radiation, λ = 0.71073 Å |
a = 12.7337 (11) Å | θ = 4.1–30.0° |
b = 6.9096 (6) Å | µ = 0.17 mm−1 |
c = 13.7852 (13) Å | T = 100 K |
β = 115.623 (11)° | Block, colorless |
V = 1093.6 (2) Å3 | 0.29 × 0.2 × 0.17 mm |
Oxford Diffraction Xcalibur3 CCD area-detector diffractometer | 1586 independent reflections |
Radiation source: fine-focus sealed tube | 1116 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.029 |
ω scan | θmax = 30.0°, θmin = 4.1° |
Absorption correction: multi-scan (ABSPACK; Oxford Diffraction, 2006 or???2005) | h = −17→16 |
Tmin = 0.894, Tmax = 0.970 | k = −9→9 |
4546 measured reflections | l = −19→16 |
Refinement on F2 | 2 restraints |
Least-squares matrix: full | Only H-atom coordinates refined |
R[F2 > 2σ(F2)] = 0.028 | w = 1/[σ2(Fo2) + (0.0275P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.054 | (Δ/σ)max < 0.001 |
S = 0.88 | Δρmax = 0.16 e Å−3 |
1586 reflections | Δρmin = −0.21 e Å−3 |
205 parameters |
CH5N4O2+·CH6N3+·2NO3− | V = 1093.6 (2) Å3 |
Mr = 289.17 | Z = 4 |
Monoclinic, Cc | Mo Kα radiation |
a = 12.7337 (11) Å | µ = 0.17 mm−1 |
b = 6.9096 (6) Å | T = 100 K |
c = 13.7852 (13) Å | 0.29 × 0.2 × 0.17 mm |
β = 115.623 (11)° |
Oxford Diffraction Xcalibur3 CCD area-detector diffractometer | 1586 independent reflections |
Absorption correction: multi-scan (ABSPACK; Oxford Diffraction, 2006 or???2005) | 1116 reflections with I > 2σ(I) |
Tmin = 0.894, Tmax = 0.970 | Rint = 0.029 |
4546 measured reflections |
R[F2 > 2σ(F2)] = 0.028 | 2 restraints |
wR(F2) = 0.054 | Only H-atom coordinates refined |
S = 0.88 | Δρmax = 0.16 e Å−3 |
1586 reflections | Δρmin = −0.21 e Å−3 |
205 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.08343 (17) | 0.1042 (3) | 0.20399 (16) | 0.0172 (4) | |
C2 | 0.34933 (15) | 0.2984 (3) | 0.14373 (16) | 0.0161 (4) | |
N1 | 0.18538 (15) | 0.0198 (3) | 0.26283 (17) | 0.0221 (4) | |
N2 | 0.03241 (17) | 0.2099 (3) | 0.25130 (16) | 0.0214 (4) | |
N3 | 0.03384 (16) | 0.0827 (3) | 0.09806 (15) | 0.0188 (4) | |
N4 | 0.24964 (13) | 0.8432 (3) | 0.03346 (13) | 0.0179 (4) | |
N5 | 0.01983 (14) | 0.5459 (3) | −0.02710 (14) | 0.0172 (4) | |
N6 | 0.30525 (15) | 0.2977 (3) | 0.03790 (14) | 0.0185 (4) | |
N7 | 0.28239 (16) | 0.3904 (3) | 0.18546 (14) | 0.0192 (4) | |
N8 | 0.44917 (14) | 0.2152 (3) | 0.20268 (15) | 0.0186 (4) | |
N9 | 0.31847 (14) | 0.4428 (3) | 0.29147 (14) | 0.0196 (4) | |
O1 | 0.06327 (12) | 0.5503 (2) | 0.07493 (11) | 0.0218 (4) | |
O2 | −0.07552 (12) | 0.6259 (2) | −0.08132 (11) | 0.0232 (4) | |
O3 | 0.07414 (12) | 0.4623 (2) | −0.07189 (11) | 0.0228 (4) | |
O4 | 0.14695 (12) | 0.9014 (2) | −0.01956 (12) | 0.0224 (4) | |
O5 | 0.30983 (12) | 0.7982 (2) | −0.01384 (12) | 0.0272 (4) | |
O6 | 0.29080 (12) | 0.8303 (2) | 0.13394 (12) | 0.0250 (4) | |
O7 | 0.41354 (12) | 0.3896 (2) | 0.35785 (12) | 0.0240 (4) | |
O8 | 0.24830 (12) | 0.5406 (2) | 0.30883 (12) | 0.0249 (4) | |
H1A | 0.217 (2) | 0.040 (4) | 0.332 (2) | 0.030* | |
H1B | 0.221 (2) | −0.049 (4) | 0.237 (2) | 0.030* | |
H2A | −0.026 (2) | 0.251 (4) | 0.217 (2) | 0.030* | |
H2B | 0.064 (2) | 0.216 (4) | 0.322 (2) | 0.030* | |
H3A | −0.031 (2) | 0.144 (3) | 0.065 (2) | 0.030* | |
H3B | 0.071 (2) | 0.029 (4) | 0.067 (2) | 0.030* | |
H7 | 0.347 (2) | 0.241 (4) | 0.010 (2) | 0.030* | |
H8 | 0.247 (2) | 0.366 (4) | 0.002 (2) | 0.030* | |
H9 | 0.486 (2) | 0.162 (4) | 0.170 (2) | 0.030* | |
H10 | 0.472 (2) | 0.206 (4) | 0.262 (2) | 0.030* | |
H11 | 0.219 (2) | 0.450 (4) | 0.143 (2) | 0.030* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0179 (9) | 0.0184 (11) | 0.0169 (11) | −0.0031 (9) | 0.0092 (9) | 0.0016 (9) |
C2 | 0.0173 (10) | 0.0144 (10) | 0.0167 (11) | −0.0025 (8) | 0.0075 (9) | 0.0022 (9) |
N1 | 0.0169 (8) | 0.0331 (12) | 0.0146 (9) | 0.0037 (8) | 0.0053 (7) | 0.0008 (9) |
N2 | 0.0197 (9) | 0.0282 (11) | 0.0141 (9) | 0.0051 (8) | 0.0052 (8) | −0.0002 (9) |
N3 | 0.0182 (9) | 0.0231 (10) | 0.0126 (9) | 0.0049 (8) | 0.0043 (7) | −0.0006 (8) |
N4 | 0.0167 (9) | 0.0192 (9) | 0.0166 (10) | −0.0025 (7) | 0.0061 (8) | −0.0009 (8) |
N5 | 0.0130 (8) | 0.0206 (10) | 0.0163 (10) | −0.0022 (7) | 0.0048 (7) | −0.0008 (8) |
N6 | 0.0187 (9) | 0.0233 (10) | 0.0114 (9) | 0.0021 (7) | 0.0047 (7) | 0.0005 (8) |
N7 | 0.0143 (8) | 0.0281 (10) | 0.0128 (10) | 0.0023 (7) | 0.0036 (7) | −0.0008 (8) |
N8 | 0.0170 (8) | 0.0262 (10) | 0.0131 (8) | 0.0024 (8) | 0.0070 (7) | 0.0017 (9) |
N9 | 0.0213 (10) | 0.0238 (10) | 0.0124 (9) | −0.0043 (7) | 0.0060 (8) | −0.0013 (8) |
O1 | 0.0197 (7) | 0.0304 (9) | 0.0130 (8) | 0.0030 (7) | 0.0050 (6) | 0.0013 (7) |
O2 | 0.0151 (7) | 0.0295 (8) | 0.0205 (8) | 0.0026 (7) | 0.0033 (6) | 0.0028 (7) |
O3 | 0.0194 (7) | 0.0291 (8) | 0.0192 (8) | 0.0030 (7) | 0.0078 (7) | −0.0025 (7) |
O4 | 0.0156 (7) | 0.0307 (9) | 0.0175 (8) | 0.0042 (6) | 0.0041 (6) | −0.0010 (7) |
O5 | 0.0219 (8) | 0.0424 (10) | 0.0206 (9) | 0.0074 (7) | 0.0123 (7) | 0.0028 (8) |
O6 | 0.0189 (7) | 0.0390 (10) | 0.0160 (8) | 0.0042 (7) | 0.0066 (6) | 0.0005 (7) |
O7 | 0.0167 (7) | 0.0375 (9) | 0.0156 (8) | −0.0007 (7) | 0.0049 (6) | 0.0002 (7) |
O8 | 0.0249 (7) | 0.0314 (8) | 0.0218 (8) | 0.0031 (7) | 0.0134 (6) | −0.0031 (8) |
C1—N2 | 1.322 (3) | N4—O6 | 1.254 (2) |
C1—N3 | 1.325 (3) | N4—O4 | 1.257 (2) |
C1—N1 | 1.332 (3) | N5—O2 | 1.246 (2) |
C2—N8 | 1.309 (3) | N5—O3 | 1.250 (2) |
C2—N6 | 1.317 (3) | N5—O1 | 1.270 (2) |
C2—N7 | 1.373 (3) | N6—H7 | 0.87 (3) |
N1—H1A | 0.87 (3) | N6—H8 | 0.84 (3) |
N1—H1B | 0.84 (3) | N7—N9 | 1.377 (2) |
N2—H2A | 0.75 (2) | N7—H11 | 0.87 (3) |
N2—H2B | 0.88 (3) | N8—H9 | 0.87 (3) |
N3—H3A | 0.86 (2) | N8—H10 | 0.74 (3) |
N3—H3B | 0.84 (3) | N9—O7 | 1.216 (2) |
N4—O5 | 1.241 (2) | N9—O8 | 1.224 (2) |
N2—C1—N3 | 120.3 (2) | O6—N4—O4 | 119.86 (18) |
N2—C1—N1 | 120.0 (2) | O2—N5—O3 | 120.81 (18) |
N3—C1—N1 | 119.8 (2) | O2—N5—O1 | 119.89 (19) |
N8—C2—N6 | 121.4 (2) | O3—N5—O1 | 119.30 (17) |
N8—C2—N7 | 123.7 (2) | C2—N6—H7 | 116.1 (16) |
N6—C2—N7 | 114.90 (18) | C2—N6—H8 | 119.8 (19) |
C1—N1—H1A | 117.5 (17) | H7—N6—H8 | 123 (3) |
C1—N1—H1B | 123.9 (17) | C2—N7—N9 | 125.70 (17) |
H1A—N1—H1B | 119 (2) | C2—N7—H11 | 120.4 (18) |
C1—N2—H2A | 118 (2) | N9—N7—H11 | 111.8 (18) |
C1—N2—H2B | 119.0 (17) | C2—N8—H9 | 117.6 (16) |
H2A—N2—H2B | 122 (3) | C2—N8—H10 | 123 (2) |
C1—N3—H3A | 114.5 (17) | H9—N8—H10 | 119 (3) |
C1—N3—H3B | 120.1 (18) | O7—N9—O8 | 126.37 (18) |
H3A—N3—H3B | 125 (3) | O7—N9—N7 | 119.05 (18) |
O5—N4—O6 | 120.27 (16) | O8—N9—N7 | 114.58 (16) |
O5—N4—O4 | 119.87 (17) | ||
N8—C2—N7—N9 | 13.7 (3) | C2—N7—N9—O7 | −7.4 (3) |
N6—C2—N7—N9 | −166.8 (2) | C2—N7—N9—O8 | 172.97 (18) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O4i | 0.87 (3) | 2.59 (3) | 3.287 (3) | 138 (2) |
N1—H1A···O5i | 0.87 (3) | 2.23 (3) | 3.058 (3) | 157 (2) |
N1—H1B···O6ii | 0.84 (3) | 2.14 (3) | 2.956 (3) | 164 (2) |
N2—H2B···O3i | 0.88 (3) | 2.63 (3) | 3.199 (3) | 123 (2) |
N2—H2B···O4i | 0.88 (3) | 2.13 (3) | 2.952 (2) | 155 (2) |
N2—H2A···O6iii | 0.75 (2) | 2.17 (3) | 2.910 (2) | 169 (3) |
N3—H3B···O4ii | 0.84 (3) | 2.04 (3) | 2.880 (3) | 175 (3) |
N3—H3A···O5iii | 0.86 (2) | 2.13 (2) | 2.988 (2) | 179 (2) |
N6—H7···O2iv | 0.87 (3) | 2.07 (3) | 2.928 (3) | 170 (2) |
N6—H8···O3 | 0.84 (3) | 2.09 (3) | 2.897 (2) | 161 (2) |
N7—H11···O1 | 0.87 (3) | 1.92 (3) | 2.766 (2) | 165 (3) |
N8—H9···O1iv | 0.87 (3) | 2.09 (3) | 2.954 (3) | 174 (2) |
N8—H10···O3v | 0.74 (3) | 2.39 (3) | 3.069 (2) | 153 (3) |
N8—H10···O7 | 0.74 (3) | 2.19 (3) | 2.660 (3) | 122 (3) |
Symmetry codes: (i) x, −y+1, z+1/2; (ii) x, y−1, z; (iii) x−1/2, y−1/2, z; (iv) x+1/2, y−1/2, z; (v) x+1/2, −y+1/2, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | CH5N4O2+·CH6N3+·2NO3− |
Mr | 289.17 |
Crystal system, space group | Monoclinic, Cc |
Temperature (K) | 100 |
a, b, c (Å) | 12.7337 (11), 6.9096 (6), 13.7852 (13) |
β (°) | 115.623 (11) |
V (Å3) | 1093.6 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.17 |
Crystal size (mm) | 0.29 × 0.2 × 0.17 |
Data collection | |
Diffractometer | Oxford Diffraction Xcalibur3 CCD area-detector |
Absorption correction | Multi-scan (ABSPACK; Oxford Diffraction, 2006 or???2005) |
Tmin, Tmax | 0.894, 0.970 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4546, 1586, 1116 |
Rint | 0.029 |
(sin θ/λ)max (Å−1) | 0.703 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.028, 0.054, 0.88 |
No. of reflections | 1586 |
No. of parameters | 205 |
No. of restraints | 2 |
H-atom treatment | Only H-atom coordinates refined |
Δρmax, Δρmin (e Å−3) | 0.16, −0.21 |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2006), CrysAlis RED (Oxford Diffraction, 2006), CrysAlis RED, SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg & Putz, 2005) and ORTEP-3 (Farrugia, 1997), SHELXL97 and ORTEP-3.
C1—N2 | 1.322 (3) | N4—O6 | 1.254 (2) |
C1—N3 | 1.325 (3) | N4—O4 | 1.257 (2) |
C1—N1 | 1.332 (3) | N7—N9 | 1.377 (2) |
C2—N8 | 1.309 (3) | N9—O7 | 1.216 (2) |
C2—N6 | 1.317 (3) | N9—O8 | 1.224 (2) |
N4—O5 | 1.241 (2) | ||
N2—C1—N3 | 120.3 (2) | O5—N4—O4 | 119.87 (17) |
N2—C1—N1 | 120.0 (2) | O6—N4—O4 | 119.86 (18) |
N3—C1—N1 | 119.8 (2) | C2—N7—N9 | 125.70 (17) |
N8—C2—N6 | 121.4 (2) | O7—N9—O8 | 126.37 (18) |
N8—C2—N7 | 123.7 (2) | O7—N9—N7 | 119.05 (18) |
N6—C2—N7 | 114.90 (18) | O8—N9—N7 | 114.58 (16) |
O5—N4—O6 | 120.27 (16) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O4i | 0.87 (3) | 2.59 (3) | 3.287 (3) | 138 (2) |
N1—H1A···O5i | 0.87 (3) | 2.23 (3) | 3.058 (3) | 157 (2) |
N1—H1B···O6ii | 0.84 (3) | 2.14 (3) | 2.956 (3) | 164 (2) |
N2—H2B···O3i | 0.88 (3) | 2.63 (3) | 3.199 (3) | 123 (2) |
N2—H2B···O4i | 0.88 (3) | 2.13 (3) | 2.952 (2) | 155 (2) |
N2—H2A···O6iii | 0.75 (2) | 2.17 (3) | 2.910 (2) | 169 (3) |
N3—H3B···O4ii | 0.84 (3) | 2.04 (3) | 2.880 (3) | 175 (3) |
N3—H3A···O5iii | 0.86 (2) | 2.13 (2) | 2.988 (2) | 179 (2) |
N6—H7···O2iv | 0.87 (3) | 2.07 (3) | 2.928 (3) | 170 (2) |
N6—H8···O3 | 0.84 (3) | 2.09 (3) | 2.897 (2) | 161 (2) |
N7—H11···O1 | 0.87 (3) | 1.92 (3) | 2.766 (2) | 165 (3) |
N8—H9···O1iv | 0.87 (3) | 2.09 (3) | 2.954 (3) | 174 (2) |
N8—H10···O3v | 0.74 (3) | 2.39 (3) | 3.069 (2) | 153 (3) |
N8—H10···O7 | 0.74 (3) | 2.19 (3) | 2.660 (3) | 122 (3) |
Symmetry codes: (i) x, −y+1, z+1/2; (ii) x, y−1, z; (iii) x−1/2, y−1/2, z; (iv) x+1/2, y−1/2, z; (v) x+1/2, −y+1/2, z+1/2. |
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Guanidinium and nitroguanidinium compounds are objects of investigation for a possible application as energetic materials (e.g., Hiskey et al., 2005; Pace & Flippen-Anderson, 1984). The crystal structures of guanidinium nitrate (GN) (Katrusiak & Szafrański, 1994, 1996) and nitroguanidinium nitrate (NGN) (Pace & Flippen-Anderson, 1984) have been determined previously. Here, we report the structure of a new nitroguanidinium nitrate-guanidinium nitrate (NGN-GN) double salt.
As for every potential energetic material, a high density is desired. The density of NGN-GN – 1.757 g.cm-3 (100 K) – is comparable to that of NGN (1.80 g.cm-3; Pace & Flippen-Anderson, 1984), and significantly higher than that of the three phases of GN (GN1, GN2 and GN3). The respective densities are for GN1: 1.458 g.cm-3 (153 K), 1.443 g.cm-3 (185 K), 1.421 g.cm-3 (257 K), 1.410 g.cm-3 (291 K), for GN2: 1.444 g.cm-3 (292 K), and for GN3: 1.400 (391 K) (Katrusiak & Szafrański, 1996).
NGN-GN contains one guanidinium and one nitroguanidinium ion and two nitrate counter-ions. The compound consists of alternating, perpendicular layers of guanidinium and nitroguanidinium cations.
The bond lengths in the guanidinium ion are similar to those found in guanidinium chloride (Haas et al., 1965). The geometry of the nitroguanidinium ion is similar to that in Bryden et al. (1956) and Pace & Flippen-Anderson (1984).
H-bonds in NGN-GN are medium to weak according to Jeffrey (1997). The only ring pattern observed is R2,2(8), and a variety of chain patterns are also observed: C2,2(6), C2,2(8) and C1,2(6) (Bernstein et al., 1995). An intramolecular H-bond is also present (N8–H10···O7).