On the Disorder in Crystalline 2,2-Dinitropropane at Room Temperature

Abstract

2,2-dinitropropane forms face-centered, cubic crystals at room temperature, with a0=8.78±0.05A, and 4 molecules per unit cell. Molecular disorder is necessarily present in the cell, and several models are examined. Excellent agreement is obtained with a model in which the molecule possesses complete orientational disorder. Although the distinction between ``rotational'' disorder in time and in space is not possible, the following mechanism is suggested: while the disorder is complete at long range, there is a high degree of order at short range.