After improving the method of recrystn. and separation of crystals from the mother liquor, La[PO2(OMe)2]3, H2O was synthesized and isolated as single crystals. The compound is triclinic, space group P1, with a 11.342(4), b 10.399(4), c 9.619(3) ? a 62.01(3), b 72.39(3), and g 66.60(3)? Z = 2 for dc = 1.94. The final R = 0.054. Each La is coordinated by 7 O atoms from 6 di-Me phosphate and 1 H2( mol., resp., forming a distorted monocapped trigonal prism. Each di-Me phosphate ligand is shared by 2 La atoms, building up a 2 dimensional network. Atomic coordinates are given.

Key words: CRYSTAL STRUCTURE DETERMINATION, LANTHANUM COMPOUNDS, PHOSPHATE, METHOXY GROUP, HYDRATE, LEAST SQUARE METHODS, RECRYSTALLIZATION