A vibrational spectroscopic study of the silicate mineral pectolite – NaCa2Si3O8(OH)

The mineral pectolite NaCa₂Si₃O₈(OH) is a crystalline sodium calcium silicate which has the potential to be used in plaster boards and in other industrial applications. Raman bands at 974 and 1026 cm(-1) are assigned to the SiO stretching vibrations of linked units of Si₃O₈ units. Raman bands at 974 and 998 cm(-1) serve to identify Si₃O₈ units. The broad Raman band at around 936 cm(-1) is attributed to hydroxyl deformation modes. Intense Raman band at 653 cm(-1) is assigned to OSiO bending vibration. Intense Raman bands in the 2700-3000 cm(-1) spectral range are assigned to OH stretching vibrations of the OH units in pectolite. Infrared spectra are in harmony with the Raman spectra. Raman spectroscopy with complimentary infrared spectroscopy enables the characterisation of the silicate mineral pectolite.