The crystals are trigonal-rhombohedral,space-group R 3,a= 11.86(l),c=9.58(l) A. Successive centres of symmetry along care occupi;d alternately by GelV and disordered GelI atoms, which are li-;;-ked by triple                                                IV                                    II Ge-O-P-O-Ge bridges(Ge -0,1.869; mean Ge -0,2.32 A). 


T J R WEAKLEY ,