Low-temperature heat capacity of beta-glycine and a phase transition at 252 K

Low-temperature heat capacity of unstable P-glycine was measured in a temperature range 5.5 to 295 K, and thermodynamic functions were calculated. At very low temperatures, heat capacity fits a sum of cubic (Debye) and linear terms: C-p=aT+bT(3). The linear contribution increases with temperature and disappears at the second-order phase transition near 252 K which was observed for the first time.