Permanent address: Department of Chemistry, University of Calabar. P.M.B. 11115 } Calabar, Nigeria. To whom correspondence should be addressed. E-mail: raj@ jncasr.ac.in: Fax: ( # ) 080-846-2766. Journal of Solid State Chemistry 156, 185 } 193 (2001) doi:10.1006/jssc.2000.8980, available online at http://www.idealibrary.com on Linear-Chain AlPOs Obtained by the Reaction of Amine Phosphates with Al 3 Ions Ayi A. Ayi,* Amitava Choudhury,*- and Srinivasan Natarajan* *Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientixc Research, Jakkur P.O., Bangalore 560 064, India; and -Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, India Received June 14, 2000; in revised form August 29, 2000; accepted October 3, 2000; published online December 21, 2000 Three one-dimensional aluminum phosphates [H 3 N(CH 2 ) 3 NH 3 ] [Al(HPO 4 )(PO 4 )], I, [H 3 NCH 2 CH(NH 3 ) CH 3 ][NH 4 ] [Al(PO 4 ) 2 ], II, [H 3 N(CH 2 ) 3 NH 3 ][N 2 H 6 O 2 ] 0.5 [Al(PO 4 ) 2 ], III, containing linear chains of corner-shared four-membered rings have been synthesized by the reaction between amine phosphates and Al 3 ions. The structures consist of macroanionic [Al(PO 4 )(HPO 4 )] 2 or [Al(PO 4 ) 2 ] 3 chains built up from AlO 4 and PO 4 tetrahedra, in which all the AlO 4 vertices are shared but each PO 4 has two terminal P+O linkages. The framework nega- tive charge is balanced by the amine related cations holding phosphate chains together through hydrogen bond interactions. The chain with the composition [Al(PO 4 )(HPO 4 )] has been observed for the 5rst time. 2001 Academic Press INTRODUCTION After the seminal work by Wilson et al. (1), a large number of aluminophosphates (AlPO-n with n representing a particular structure type) have been reported encompass- ing a wide range of structure types both zeolitic and novel. Structurally, most AlPO-n phases are exclusively composed of AlO and PO primary building units although a few contain AlO and AlO units (2, 3). Of the many AlPOs, structures with three-dimensional structures, e.g., AlPO-5 (SSZ-23) (1) and AlPO-34 (chabazite) (1), and two-dimen- sional structures, e.g., [NH (CH ) NH ]  [Al (PO ) ] (4) and [NH (CH ) NH ][Al (OH) H O(PO ) ]H O (5) are more common than the one-dimensional ones. The one- dimensional AlPOs exist in two distinct forms, an edge- shared ladder (6, 7) and a corner-shared chain (8, 9). Of these, the ladders are prominent. The ladder structures contain a backbone of edge-shared four-membered rings and possess additional pendant H PO or HPO units. The chains, on the other hand, are made from a corner sharing of AlO and PO tetrahedra and contain no pendant groups, the chain compositions being [Al(PO ) ] (8a), [Al(HPO ) ](8b). Recently it has been shown that the reaction of metal ions with amine phosphates o!ers a facile route for the synthesis of open-framework materials (10). Using this method, a layered AlPO possessing tancoite-type structure (11) has been synthesized (5). In continuation of the theme, we have now isolated and characterized three one-dimensional AlPOs of the composition, [H N(CH ) NH ][Al(HPO )(PO )], I, [H NCH CH (NH )CH ] [NH ][Al(PO ) ], II, [H N(CH ) NH ] [N H O ]  [Al(PO ) ], III, by the reaction of Al ions with amine phosphates. The solids form into two distinct types possessing the chain compositions of [Al(PO )(HPO )] and [Al(PO ) ]. The chain com- position, [Al(PO )(HPO )], has been observed for the "rst time, though the same composition is known in gallium phosphate chains (12). In this paper we present the synthesis and structures of the one-dimensional phosphates which are rather uncommon compared to the two- and three-dimen- sional phosphate structures. EXPERIMENTAL The compounds I }III were synthesized by the reaction of Alions with 1,2-diammoniumpropane phosphate (1,2- DAP-P) and 1,3-diammoniumpropane phosphate (1,3- DAP-P). These amine phosphates were prepared by stan- dard procedure (13). While the structure of 1,3-DAP-P is known (13), that of 1,2-DAP-P was established in this study. In a typical synthesis as in the case of I, 0.117 g of Al(OH) was dispersed in 0.54 ml of water, followed by the addition of 0.14 ml of dioxane and 0.25 ml of HCl. Finally, 0.856 g of 1,3-DAP-P was added to above under constant stirring to result in a homogeneous gel. The gel was transfer- red, sealed in a PTFE-lined stainless steel acid digestion bombs and heated at 1803C for 48 h. The resulting product, a crop of "ne needles, was vacuum "ltered and dried at 185 0022-4596/01 $35.00 Copyright 2001 by Academic Press All rights of reproduction in any form reserved.