Keywords: E; P, As, Sb or Bi; M; Lewis acid atom usually metal or metalloid; X; F, Cl, Br or I; R; alkyl or aryl; DMPP; tris(2,6-dimethoxyphenyl)phosphine; TMPP; tris(2,4,6-trimethoxyphenyl)phosphine; HCB; closo-2-{(dimethylphosphino)methyl}-1,2-dicarbaborane; MOCV