Theory:0.23 Be0(0.22) ZnS MgTe(0.29) InP,GaAs (Smallest S,Se,Te salts Cation/Anion) of Zn,Cd,Hg CscI NaCl (Biggest Cation/Anion) (Intermediate Cation/Anion) XIlI-12CsCl NaCl ZnS (Biggest Cation/Anion) (Smallest Cation/Anion) (Intermediate Cation/Anion) Theory: 0.23 BeO (0.22) MgTe (0.29) InP, GaAs S, Se, Te salts of Zn, Cd, Hg XIII-12