Infrared study of the carbonate minerals

Infrared spectra of 27 common and rate carbonates are described. Each carbonate shows characteristic absorption bands, some of which difier more or less from published curves. Among the isomorphous members of the calcite, dolomite, and aragonite groups, a noteworthy shift of absorption bands takes place with longer wave lengths corresponding to an increase in cation radius or mass. The spectral difference between the more common groups may be related to crystal structure. The spectral relationships among the minerals of several groups are not well known, due to the complicated composition and crystal structure. Infrarecl active groups of CO:, HCOr, HrO, OH, and SOr dominate the absorption characteristics.