ALUMINUM PHOSPHATES WITH NONCENTROSYMMETR IC LAYER-STRUCTURE AND FRAMEWORK-STRUCTURES OF TOPOLOGICALLY RELATED MOTIFS - 2 - KAL2(PO4)(2)(OH)CENTER-DOT-2H(2)O

KAl2(PO4)(2)(OH). 2H(2)O was obtained by the reaction of gibbsite with a potassium-phosphate solution of pH = 5.5 at 373 K. A single crystal X-ray structure analysis showed that it is an ordered, F-free K-analo g of the microporous compound AlPO4-CI2. Crystal data: orthorhombic sp ace group P2(1)2(1)2(1), a = 920.5(1), b = 970.7(2), c = 982.8(2) pm, Z = 4. The structure consists of dimeric units of AlO6 octahedra and A lO5 trigonal bipyramids, bridged by an OH and two bidentate phosphate groups. The dimers are linked by phosphate to form corrugated layers w hich are topologically related to the layers in KAl2(PO4)(2)(OH). 4H(2 )O and minyulite. The layers are connected by Al-O-P and hydrogen bond s to a three dimensional framework structure with K ions in channel-li ke cavities. A neutron powder scattering experiment with KAl2(PO4)(2)( OD). 2D(2)O showed that the bridging OD group and only one D of each w ater molecule are involved in hydrogen bonding. P-31 MAS NMR spectra s how two isotropic lines at delta(iso) = -6.9 and -18,7 ppm of the inte nsity ratio 1:1 and confirm the presence of two crystallographically i ndependent P atoms in the unit cell. In the H-1 MAS NMR spectra the wa ter molecules and the bridging OH group show signals at 5.9 and 1.1 pp m, respectively.