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The 'zeolitic' MXO4-based framework (M = Zn, Be, X = P, As) structure field has recently been shown to be a very extensive one by ourselves and others. A seemingly general feature of these new zeolitic (Zn/Be,P/As,O)- framework phases is a preference for a 1:1 M to X ratio and strict alternation of MO4 and XO4 tetrahedra, akin to a 'Lowenstein's rule' Al-O-Al avoidance and consequent Si/Al Tetrahedral alternation for 1:1 Si to Al ratio aluminosilicate phases. This feature would appear to militate against Zn/Be,P/As,O molecular sieves with odd- as opposed to even-membered ring systems, and also against phases whose M:X ratio is non-unity. We describe the preparations, structures and properties of two new phases; a zincophosphate, Na2ZnPO4OH(dot)7H2O (NaZnPO) , and a berylloarsenate, Be2AsO4OH(dot)4H2O (BeAsO), which are non-zeolitic, but contain 1-dimensional chains, whose building blocks include tetrahedral 3-rings.

Two new titanium pyroarsenate phases, alpha-TiAS2O7 and beta-TiAS2O7, have been prepared by high temperature hydrothermal methods and characterized by single crystal x-ray diffraction techniques. Both structures are based on different three-dimensional networks of vertex-sharing TiO6 octahedra and AsO4 tetrahedra. The TiO6 groups show little distortion from regular octahedral geometry, and the arsenate anions are linked in pairs via As-0-As bonds to form pyroarsenate (AS207) groups. Alpha-TiAS2O7 is isostructural with a polymorph Of SiP2O7; beta-TiAS207 is a new structure., Prepared in cooperation with Houston Univ., and California Univ., Dept of Chemistry.

The synthesis and structure of Zn4O(BO3)2, a new, neutral-framework, microporous zincoborate are reported. The crystal structure of Zn4O(BO3)2 has been solved ab initio from laboratory X-ray powder diffraction data, and consists of a network of vertex-sharing tetrahedral ZnO4 and triangular B03 moieties enclosing interlinked, 'cigar'-shaped cages and a three-dimensional network of intersecting channels (minimum diameter approx. 3.5 A). The 'fused' 3-ring/5-ring connectivity of the Zn/B/O framework is novel. Crystal data: Zn4O(BO3)2, M sub r = 384.37, rhombohedral, space group R3c (No. 167), a = 9. 9115 (4) A, alpha = 48.602 (1) deg, V = 502.61 A sup 3, Z = 3, R sub p = 10.9%, R sub wp = 14.2% for 4198 powder data (Cu K alpha radiation, lambda = 1.54178 A) .

The high-temperature/high-pressure hydrothermal synthesis and X-ray single crystal structure of Be3(AsO4)2(dot)2H2O is described: the title compound contains a three-dimensional network of BeO4 and AsO4 tetrahedra. The structural motif includes infinite layers of 'bridged' tetrahedral 3- and 4-rings. 9Be MAS NMR data are consistent with the Be-atom environments in the crystal structure.

The synthesis, structure and some properties of a new, anhydrous, zinc ethyl phosphate are described. Zn(02P(OC2H5)2)2) (ZnPOEt) crystallizes in the monoclinic space group C2/(No. 15) with a = 22.176(6), b = 8.042(2), c = 9. 0883 (3) A, B = 96.553 (8)0 V = 1610 A3, Pcalc = 1.533 g/cm3, u = 17.8 cm-1 and Z = 4, with R(Fo) = 6.94% for 658 observed reflections (I > 3a(I)). The novel structure consists of infinite 1-dimensional chains of vertex-linked zinc-oxygen and phosphorous-oxygen tetrahedra forming 4-rings l two of the phosphate P-0 vertices are coordinated to ethyl (-C2H5) groups, and the herringbone crystal packing is determined by van der Waals' forces between these terminal organic groups. Physical (TGA, DSC) and spectroscopic data (IR, 1H and 31P NMR) are presented. The physical data show a melting, followed by a decomposition reaction, eventually resulting in Zn(PO3)2. ZnPOEt is soluble in and recrystallizable from several polar and non-polar solvents: the NMR data suggest that ZnPOEt maintains a polymeric state in solution. ZnPOEt is contrasted with its sulphur-containing analogue, Zn(S2P(OC2H5)2)2.

We report synthesis and single-crystal structure of Li8(HPO4)(BePO4)6-H2O (BePO-LOS) which is a topological equivalent of the synthetic low-sodium aluminosilicate zeolite losod, Na6(AlSiO4)6-9H2O (structure code: LOS). Crystal data for BePO-LOS: trigonal, space group P31c (No. 159), alpha + 11.504 (2) A, c = 9.273 (2) A V = 1062.8 cubic-A, Z = 2.R = 4.63%, R sub w = 4.88% for 1053 observed reflections with I . 3o(I). Refined framework-atom bond distances D SUB AVE(Be-O) = 1.624 (4) A, d sub ave(P-O) = 1.531 (2) A reflect the fully-ordered distribution of Be and P-atoms over the framework tetrahedral nodes. The extra-framework lithium cations are in typical tetrahedral geometry (3 framework oxygen atomis + 1 extra framework oxygen atom), while the included hydrogen phosphate anion, coordinated by lithium cations within the loso-cage, is novel. The structure of BePO-LOS is considered in relationship to other BePO sieves characterized recently., Prepared in cooperation with University of Houston, Department of Chemistry, Houston, TX.