Cs₂Al₂P₂O₉: an exception to Löwenstein’s rule. Synthesis and characterization of a novel layered aluminophosphate containing linear Al–O–Al linkages

Abstract

A caesium aluminophosphate compound synthesized via high-temperature, solid-state methods reveals a new composition for a layered AlPO structure; it exhibits a non-Löwensteinian framework which contains linear Al–O–Al linkages in six-rings of alternating Al₂O₇ and PO₄ groups.

References

1. (a) S. Oliver, A. Kuperman and G. A. Ozin, Angew. Chem., Int. Ed., 1998, 37, 46; (b) L. Vidal, V. Gramlich, J. Patarin and Z. Gabelica, Chem. Lett., 1999, 201; (c) J. Yu, J. Li, K. Sugiyama, N. Togashi, O. Terasaki, K. Hiraga, B. Zhou, S. Qiu and R. Xu, Chem. Mater., 1999, 7, 1727 and references cited therein.
2. W. Löwenstein, Am. Mineral., 1954, 39, 92.
3. (a) R. M. Barrer and J. Klinowski, Philos. Trans. R. Soc., London A., 1977, 285, 636; (b) R. G. Bell, R. A. Jackson and C. R. A. Catlow, Zeolites, 1992, 12, 870; (c) C. R. A. Catlow, A. R. George and C. M. Freeman, Chem. Commun., 1996, 1311.
4. (a) S. E. Tarling, P. Barnes and J. Klinowski, Acta Crystallogr., Sect. B, 1988, 44, 128; (b) K.-F. Hesse and L. Cemic, Z. Kristallogr., 1994, 209, 346; (c) K.-F. Hesse and L. Cemic, Z. Kristallogr., 1994, 209, 660.
5. 0.0540 g of Al (2.0 mmol), 0.1422 g of KO₂(2.0 mmol), 0.0795 g of CuO (1.0 mmol) and 0.1419 g of P₂O₅(1.0 mmol) were ground and mixed with the flux CsCl. The charge to flux ratio was 1:2 by weight. The reaction was carried out in a carbon-coated quartz ampoule. The mixture was heated up to 500 °C over 24 h, and isothermed for 6 h, followed by heating to 800 °C, and isothermal treatment for an additional 4 d. The reaction was cooled slowly to 500 °C over 72 h, followed by furnace cooling to room temperature. Colorless columnar crystals of 1(ca. 60%), as well as some other unidentified black and white polycrystalline phases (ca. 40%), were retrieved from the flux by washing the products with deionized water using suction filtration. EDAX shows no contamination from potassium, chlorine, and copper in this crystalline phase, as the presence of the latter is attributed to CuO used for the synthesis of Cu-containing AlPO. An alternative reaction of 2Al/2KO₂/P₂O₅/4CsCl without adding CuO resulted in a slightly lower yield of 1, ca. 50%.
6. Crystal datafor 1: Cs₂Al₂P₂O₉, M= 525.7, triclinic, space group P1̄(No. 2), a= 4.925(2), b= 7.121(2), c= 8.066(2)Å, α= 96.51(2)°, β= 107.12 (2)°, γ= 108.68(2)°, V= 249.3(1)ų, Z= 1, D_c= 3.502 g cm^–3, µ(Mo-Kα)= 7.835 mm^–1, λ= 0.71073 Å, 3.50° < 2θ <55.00°. Final R= 0.024, R_w= 0.035, GOF = 1.36 were obtained for all the data and 71 parameters. The final Fourier map had a minimum and maximum of –1.04 and 1.60 eÅ^–3, respectively. CCDC 182/1446. See http://www.rsc.org/suppdata/cc/1999/2343/ for crystallographic files in .cif format.
7. (NH₃CHMeCH₂NH₃)₃[Al₆P₈O₃₂]·H₂O: I. D. Williams, Q. Gao, J. Chen, L. Y. Nagi, Z. Lin and R. Xu, Chem. Commun., 1996, 1781 Co(en)₃[Al₃P₄O₁₆]·3H₂O: K. Morgan, G. Gainsford and N. Milestone, J. Chem. Soc., Chem. Commun., 1995, 425 trans-Co(dien)₂-[Al₃P₄O₁₆]·3H₂O: D. A. Bruce, A. P. Wilkinson, M. G. White and J. A. Bertrand, J. Solid State Chem., 1996, 125, 228 (2-BuNH₃⁺)₂-[HAl₂P₃O₁₂]: A. M. Chippindale, A. V. Powell, L. M. Bull, R. H. Jones, A. K. Cheetham, J. M. Thomas and R. Xu, J. Solid State Chem., 1992, 96, 199.