SYNTHESIS AND CRYSTALLOGRAPHIC X-RAY DETERMINATION OF A NEW LAYERED FLUOROALUMINOPHOSPHATE - ALF(HPO4), ETHYLENEDIAMINE

This paper deals with the synthesis and the X-ray determination of the structure of hitherto unknown AlF(HPO4), ethylenediamine (en). This monoclinic phase crystallizes in space group P 21/c with unit cell parameters a = 9.2855(6), b = 7.0832(4), and c = 9.6492(5) Å β = 101.544(6)°; V = 621.80(9) Å3; and Z = 4. AlF(HPO4), en is a layered compound with sheets stacked along the a axis. These sheets are built up from isolated trans-chains of Al(O3F2N) octahedra running along [010]. PO4 tetrahedra ensure the linkage between the chains via three of their four vertices. The diamine plays two roles: it participates in the octahedral coordination of aluminium via the N(1) atom but also ensures the cohesion between the sheets by hydrogen bonds. This structure is closely related to α-VO(HPO4) · 2H2O. © 1993 Academic Press, Inc.