Survery of tetrahedral structures

Abstract

Structures built from tetrahedral AX4 groups that share some or all of their X atoms may be classified according to the numbers of tetrahedra to which the X atoms belong. If vxis the number of X atoms of each AX4 group in a structure of composition A mXn which are common to x such groups (that is, is the coordination number of X) then Hvx — 4 and Jj {vx/ x) — The solutions of these equations for any composition A mXn may be examined systematically. The present survey is restricted to structures which can be constructed from regular tetrahedral AX4 groups, all of which share their X atoms in the same way and have no X—X separations shorter than the edge of a tetrahedron. A study is made of the types of possible structure, finite, one-, two- or three-dimensional, and the emphasis is on the topology rather than the geometry of the structures.