A vibrational spectroscopic study of the silicate mineral plumbophyllite Pb2Si4O10.H2O.

Abstract

Raman spectroscopy complimented with infrared spectroscopy has been used to study the molecular structure of the mineral of plumbophyllite. The Raman spectrum is dominated by a very intense sharp peak at 1027 cm^-1, assigned to the SiO stretching vibrations of (SiO3)n units. A very intense Raman band at 643 cm^-1 is assigned to the bending mode of (SiO3)n units. Raman bands observed at 3215, 3443, 3470, 3494 and 3567 cm^-1 are assigned to water stretching vibrations. Multiple water stretching and bending modes are observed showing that there is much variation in hydrogen bonding between water and the silicate surfaces. Because of the close similarity in the structure of plumbophyllite and apophyllite, a comparison of the spectra with that of apophyllites is made. By using vibrational spectroscopy an assessment of the molecular structure of plumbophyllite has been made.