OrderVersusDisorder in Ternary Structures Including Certain Spinels

摘要

The doubling process as the second alternative suggested by Professor M. v. Laue for mixcrystals is followed through in the case of lithium ferrite and it is shown in that case that all superlattice lines disappear when the lattice edge is eight times as large as the small disordered lattice found by Posnjak and Barth. It is shown that for this large (33A) lattice thesimplespace group,O1h, gives only facehyphen;centered lines on the powder photograph. The disappearance of the superlattice lines for this lattice may be said to be due to the coherence of the xhyphen;rays that cause the destructive interference involved.