Physical and chemical transformations of sodium cyanide at high pressures
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, Immm), to NaCN-IIB (orthorhombic, Pmmn) at 4 GPa, to NaCN-III (monoclinic, Cm) at 8 GPa, and to NaCN-IV (tetragonal, P4mm) 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 1550 cm{sup -1}, indicating the formation of C = N 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.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1005956
- Journal Information:
- J. Chem. Phys., Vol. 131, Issue (14) ; 2009; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- ENGLISH
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