Ionicity dependence of defect reactions and negative-U states in glasses, II

The analysis of defects and their reactions is continued from paper I and applied to amorphous alloys of chalcogens with group IV and V elements. It is calculated that it is difficult to overcoordinate a pnictide element, in agreement with the experimentally determined dangling-bond character of P2°. Four types of defect are possible in locally stoichiometric SiO2. The Dc + is concluded to be probably O3 +(Si3 +), while both the D° sites are dangling bonds.