A vibrational spectroscopic study of planchéite Cu8Si8O22(OH)4•H2O.

Planchéite Cu8Si8O22(OH)4•H2O is a hydrated copper hydroxy silicate. Raman spectroscopy complimented with infrared spectroscopy has been used to determine the molecular structure of planchéite. Raman bands at around 1048, 1081 and 1127 are described as the ν1-SiO3 symmetric stretching vibrations; Raman bands at 828, 906 are attributed to the ν3-SiO3 antisymmetric stretching vibrations. The Raman band at 699cm−1 is assigned to the ν4 bending modes of the —SiO3 units. The intense Raman band at 3479cm−1 is ascribed to the stretching vibration of the OH units. The Raman band at 3250cm−1 is evidence for water in the structure. [ABSTRACT FROM AUTHOR]