COMPUTER-SIMULATION OF CATION DISTRIBUTION IN DIOCTAHEDRAL 2-1 LAYER SILICATES USING IR-DATA - APPLICATION TO MOSSBAUER-SPECTROSCOPY OF A GLAUCONITE SAMPLE

A new approach is described to computer simulate cation distribution in octahedral sheets of dioctahedral 2:1 layer silicates with vacant trans-octahedra. This approach makes use of the information on cation distribution at the one-dimensional level provided by integrated IR optical densities for the region of OH-stretching frequencies. By using this program it is possible to show that (1) the Mossbauer spectrum of glauconite B. Patom conforms to the structural model composed of celandonite-like and illite-like domains whose dimensions are limited by approximately 2 or 4 unit cells; (2) non-equivalency of ''left'' and ''right'' cis-positions (with fixed b-direction) with respect to R2+ and R3+ occupancy is a characteristic feature of a celadonite-like domain.