The formation of the plastic crystal phase in several pentaerythritol derivatives

Several substituted pentaerythritol compounds [R—C(CH₂OH)₃, where R = COOH, CH₃, NO₂ and NH₂] have been found to undergo phase transitions to plastic crystals. With the exception of R = NH₂ (which has only one detectable diffraction line in the plastic state), the crystals are f.c.c., a ≃ 8.9 Å.