Pressure-induced physical and chemical transformations of sodium cyanide (NaCN) have been studied up to 50 GPa in diamond-anvil cells, using micro-Raman spectroscopy and angle-resolved synchrotron x-ray diffraction. We observe three phase transitions in this pressure range: NaCN-IIA (orthorhombic, ), to NaCN-IIB (orthorhombic, ) at 4 GPa, to NaCN-III (monoclinic, ) at 8 GPa, and to NaCN-IV (tetragonal, ) at 15 GPa, which is stable to 25 GPa. At higher pressures, NaCN-IV undergoes an irreversible chemical change, which occurs over a large pressure range between 25 and 34 GPa. The new material exhibits a broad yet strong Raman band at around , indicating the formation of bonds in a similar configuration of carbon graphite. The absence of sharp diffraction lines in this material suggests an amorphous nature of CN polymer products.
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Research Article| October 09 2009
Physical and chemical transformations of sodium cyanide at high pressures
Jing-Yin Chen, Choong-Shik Yoo; Physical and chemical transformations of sodium cyanide at high pressures. J. Chem. Phys. 14 October 2009; 131 (14): 144507. https://doi.org/10.1063/1.3245861
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