SYNTHESIS AND STRUCTURE OF A CHAIN ALUMINOPHOSPHATE FILLED WITH [NH4](+) AND [H3NCH2CH2NH3](2+) CATIONS

The compound [AIP(2)O(8)](3-)[NH3CH2CH2NH3](2+)[NH4](+) (designated AL PO-enA, where enA stands for ethylenediammonium and ammonium cations) has been synthesized from the non-aqueous system H3PO4-Al(Oi-Pr)(3)-NH 2CH2CH2NH2-HOCH2 CH2OH-H2O. The structure of the compound has been cha racterized by single crystal X-ray diffraction to be orthorhombic with space group Peen and unit cell dimensions a 8.0330(10), b = 16.989(2) , c = 8.740(2) Angstrom and Z = 4. The final R(1) and wR(2) values wer e 0.0309 and 0.0706. The structure consists of macroanionic [AlP2O8](3 -) chains built up from AlO4 and PO4 tetrahedra, in which all AlO4 ver tices are shared but each PO4 has two terminal P-O groups. The cations which balance the negative charges of the chains are [NH3CH2CH2NH3](2 +) and [NH4](+), the latter being believed to arise from the fragmenta tion of the former during crystallization. Additional characterization of the compound by powder XRD, SEM, IR spectroscopy, inductively coup led plasma analysis (ICP), TGA, and DTA are also described. (C) 1996 A cademic Press.