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Updated: Apr 26, 2026

Synthesis and Microdiffraction at Extreme Pressures and Temperatures
Published on: October 7, 2013
Structure of intermediate phase II of LiNH2 under high pressure
Hiroshi Yamawaki1, Hiroshi Fujihisa, Yoshito Gotoh
1National Institute of Advanced Industrial Science and Technology (AIST) , AIST Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
Abstract:
A new intermediate phase (phase II) was found between phases I and III in LiNH2 in the pressure range of 10 to 13 GPa through the analysis of infrared and powder X-ray diffraction measurements to 25 GPa at room temperature. This result agreed with the prediction of a stable phase between phases I and III through theoretical calculations. Powder X-ray diffraction measurement and DFT calculation showed that this phase has a monoclinic structure with space group C2/c (Z = 8), which is the same structure as that of a slightly tilted crystal lattice of the Fddd structural model. The enthalpy of the C2/c structure was also found to be almost the same as that of the Fddd structure.
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