Heat Capacity and Thermal Expansion of NH3CH2COOH·H2PO3

Heat capacity of glycinium phosphite was measured by adiabatic calorimetry in a temperature range from 90 K to 300 K. A λ-type anomaly characteristic of the second order phase transition was observed at 224.3 K (TC). The jump of the heat capacity at TC is estimated as δc=7.1±0.2 J K-1 mol-1. The tra...

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Bibliographic Details
Published in:Journal of the Physical Society of Japan 2004-07, Vol.73 (7), p.1812
Main Authors: Shikanai, Fumihito, Hatori, Junko, Komukae, Masaru, Czapla, Zbigniew, Osaka, Toshio
Format: Article
Language:English
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Summary:Heat capacity of glycinium phosphite was measured by adiabatic calorimetry in a temperature range from 90 K to 300 K. A λ-type anomaly characteristic of the second order phase transition was observed at 224.3 K (TC). The jump of the heat capacity at TC is estimated as δc=7.1±0.2 J K-1 mol-1. The transition enthalpy and transition entropy were estimated as δH=82.20±0.07 J mol-1 and δS=0.40±0.01 J K-1 mol-1 respectively. Thermal expansions of the crystal were also measured along the crystallographic a, b and c axes using the strain gages. The volume thermal expansion shows clear anomaly at TC. The jump of thermal expansion coefficient at TC is estimated as δαv=-2.7±0.3×10-5 K-1.
ISSN:0031-9015
1347-4073