A New Class of Flexible Energetic Salts: The Crystal Structures of the Ammonium, Lithium, Potassium, and Cesium Salts of Dinitramide

The crystal structures of the ammonium, 1, lithium,
2, potassium, 3, and cesium, 4, salts
of a new nitrogen
oxy anion, N3O4-, have been
determined. In 1 there are two interpenetrating
three-dimensional lattices linked by
strong hydrogen-bonding interactions between all four ammonium protons
and three of the four dinitramide oxygen
atoms. Even though 2−4 have similar
formula units each has a completely different structure characterized
by
differing coordination numbers and geometries. The structure of
2 is unique in that it is the only one containing
a
dinitramide ion in the C2 conformation predicted
by ab initio studies to be the minimum energy
conformation.
There is good agreement between the predicted and experimental
metrical parameters for the C2 conformer of
the
dinitramide anion.