“…Three types of tetrahedral P, one type of tetrahedral A1 and two types of trigonalbipyramidal A1 occur in A1PO4-21 (Bennett, Cohen, Artioli, Pluth & Smith, 1985;Parise & Day 1985), and the 1,3-propanediamine molecule used in the synthesis of crystals studied by Bennett et al (1985) split into three triatomic species encapsulated by the framework. The other aluminophosphates encapsulated intact organic species: A1PO4-12 (Parise, 1984a), A1PO4-EN3 (Parise, 1985), A1PO4-17 (Pluth, Smith & Bennett, 1986). Among the other aluminophosphate structures reviewed by Bennett, Dytrych, Pluth, Richardson & Smith (1986), those of particular interest here are variscite (Kniep, Mootz & Vegas, 1977), metavariscite (Kniep & Mootz, 1973) and a synthetic material A1PO4.1.5H20 (Pluth & Smith, 1985 with an X-ray powder pattern resembling that of H 3 (d 'Yvoire, 1961).…”