Designation of cation sites in pyroxenoids

Abstract

Cation sites in pyroxenoids may be classified into two groups; those in one group has been designated as M1i (i=0, 1, 2,···), and those in the other as M2j (j=1, 2, ···). The configuration of silicate chains is mainly controlled by the size of cations at M1i. The proposed notation has much advantage in discussing crystal chemistry of pyroxenoids because in a given structural series, octahedra (or polyhedra) about sites having the same symbol share, regardless of structural type, geometrical features in common.