This study is an experimental and theoretical investigation of cation and anion distributions in minerals. Experimental study of cation distributions will primarily use the method of electron-channeling (ALCHEMI) with supporting studies using x-ray and neutron diffraction. There are two main objectives of the cation studies. The first is to make a detailed assessment of the errors in ALCHEMI by comparing results of channeling experiments on a number of phases with occupancies determined on the same samples by other well-established methods. The second objective is to exploit some of the unique advantages of the method in conducting qualitative and semi-quantitative determinations of site occupancies and site preferences in a number of geologically and geophysically significant minerals.
