“…. It has been found in, for example, K 3 P 3 O 9 (Bagieu-Beucher et al, 1976), Na 3 P 3 O 9 (Ondik, 1965), CsCdP 3 O 9 (Averbuch-Pouchot & Durif, 1977), CdK 4 (P 3 O 9 ) 2 Á2H 2 O (Averbuch-Pouchot, 1978), BaKP 3 O 9 Á-H 2 O (Seethanen & Durif, 1978) and NH 4 CaP 3 O 9 (Masse et al, 1975). We report here the synthesis and structural characterization of the condensed phosphate CsCaP 3 O 9 , (I), which is isotypic with CsCdP 3 O 9 (Averbuch-Pouchot & Durif, 1977).…”