Journal of Applied Crystallography

Volume 36, Part 6 (December 2003)

J. Appl. Cryst. (2003). 36, 1334-1341 [doi:10.1107/S0021889803016182]

Energetic materials: variable-temperature crystal structures of two biguanidinium dinitramides

N. B. Bolotina, M. J. Hardie and A. A. Pinkerton

Abstract: The crystal structures of the energetic materials biguanidinium mono-dinitramide C₂H₈N₅⁺.N₃O₄^-, (BIGH)(DN), and biguanidinium bis-dinitramide C₂H₉N₅²⁺.2N₃O₄^-, (BIGH₂)(DN)₂, have been determined at several temperatures in the range 85-298 K using single-crystal X-ray diffraction techniques. The thermal expansion second-rank tensors have been determined to describe the thermal behavior of the crystals studied. Strongly anisotropic thermal expansion is most important in the direction perpendicular to the least-squares planes of the dinitramide ions in both cases, suggesting that the atomic thermal motion is significantly anharmonic in these crystals. Anharmonicity of thermal motion is also evident from the non-linear temperature dependence of the atomic displacement parameters. Rigid-body analysis of thermal motion both of dinitramide anions and of biguanidinium cations was performed using the libration and translation second-rank tensors. For both compounds, the libration thermal motion is strongly anisotropic with the dominating libration axes oriented in a similar manner in both anions and cations. Although the translation motion of the ions is not strongly anisotropic, the axes of largest thermal displacements are close to the directions of greatest thermal expansion of the crystals.

Online 15 November 2003


	Structure factor file (CIF format) (100.6 kbytes) Contains datablock I100K

	Structure factor file (CIF format) (101.0 kbytes) Contains datablock I150K

	Structure factor file (CIF format) (102.1 kbytes) Contains datablock I200K

	Structure factor file (CIF format) (102.8 kbytes) Contains datablock I250K

	Structure factor file (CIF format) (103.8 kbytes) Contains datablock I298K

	Structure factor file (CIF format) (67.4 kbytes) Contains datablock II85K

	Structure factor file (CIF format) (67.5 kbytes) Contains datablock II100K

	Structure factor file (CIF format) (68.3 kbytes) Contains datablock II150K

	Structure factor file (CIF format) (69.0 kbytes) Contains datablock II200K

	Structure factor file (CIF format) (69.3 kbytes) Contains datablock II250K

	Structure factor file (CIF format) (69.7 kbytes) Contains datablock II298K

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