Thermodynamic stability and structure of nitrogen hydrate crystal

Abstract

Stability boundary for the nitrogen hydrate system is investigated in a temperature range from 285 to 310 K and pressure range up to 440 MPa. The present experimental results show that nitrogen hydrates form structure-II without any solid–solid phase transition in the present experimental conditions. The strong pressure dependence of intermolecular O–O vibration reveals that hydrate cage is shrunk by pressurization.