INFRARED SPECTRA OF TRIOCTAHEDRAL CHLORITES IN RELATION TO CHEMICAL COMPOSITION

Abstract

Infrared absorption spectra in the 4000-400 cm^-1 range of natural trioctahedral chlorites of the Mg-Fe series (orthochlorites) are presented with some discussions on the relationship to chemical composition. The octahedral composition can be estimated by the natures of the bands at 3680-3615 cm^-1, in the 700-600 cm^-1 range, and at 470-410 cm^-1. The bands in the 3620-3400 cm^-1 range, in the 1100-900 cm^-1 range, and at about 750 cm^-1 give approximate tetrahedral composition. A composition determinative graph has been prepared. In addition, the infrared method is shown to be useful occasionally for identification of mixtures of chlorites having different compositions.