2,2,2-Trinitroethanol, 2,2-dinitropropanol and 2,2-dinitropropanediol-1,3 undergo enantiotropic transitions at 39.3°C, 9.1°C and 68.0°C, respectively. All of the high temperature forms (II) are cubic and possess properties of the plastic crystalline state. A differential scanning calorimeter was used to measure the heats of transition: 2,2,2-trinitroethanol, 4.3 kcal/mole; 2,2-dinitropropanol, 3.6 kcal/mole; and 2,2-dinitropropanediol-1,3, 5.1 keal/mole. The difference between the heat of transition of each nitroalcohol and its corresponding nitroallrane has been interpreted as a measure of hydrogen bonding energy in the low temperature form (I) of the alcohol. Hydrogen bonding energies (keal/mole) of 2,2,2-trinitroethanol-I, 2,2-dinitropropanol-I and 2,2-dinitropropanediol-1,3-I are 3.2, 0.8 and 2.3, respectively. The heats of fusion of 2,2,2-trinitroethanol and 2,2-dinitropropanol also were obtained.