Together with the MI ions, the tetrahedral ribbons of the title compounds form double helices, the central channels of which are filled with water helices (see picture). Coordination octahedra MIIO4(H2O)2 link the spiral ribbons, which run parallel to one another. Partial dehydration of the title compounds leads to microporous phases with channeled structure and is reversible in the sense of a topochemical reaction.
Crystals of NaZn(H2O)2[BP2O8].H2O were grown under mild hydrothermal conditions at 170 degrees C. The crystal structure (solved by X-ray single-crystal methods: hexagonal, P6(1)22 (no. 178), a = 946.2(2), c= 1583.5(1) pm, V= 1227.8(4).10(6) pm3, Z = 6) exhibits a chiral octahedral-tetrahedral framework related to the CZP topology and contains helical ribbons of corner-linked borate and phosphate tetrahedra. Investigation of the thermal behavior up to 180 degrees C shows a (reversible) dehydration process; this leads to the microporous compound Na[ZnBP2O8].H2O, which has the CZP topology. The crystal structure of Na[ZnBP2O8].H2O was determined by X-ray powder diffraction by using a combination of simulated annealing, lattice-energy minimization, and Rietveld refinement procedures (hexagonal, P6(1)22 (no. 178), a = 954.04(2), c = 1477.80(3) pm, V= 164.88(5).10(6) pm3, Z = 6). The essential structural difference caused by the dehydration concerns the coordination of Zn2- changing from octahedral to tetrahedral arrangement.
Tetrahedral framework structures with topologies that show close relationships to the feldspar group or to gismondine are formed by the zincoborophosphates A[ZnBP(2)O(8)] (see picture). The compounds are readily accessible under mild hydrothermal conditions (T(max)=170 degrees C) and are thermally remarkably stable (for example, 940 degrees C for A=Cs). Metalloborophosphates are a new class of compounds, which are expected to provide access to zeolite-like microporous systems.
Tetrahedral framework structures with topologies that show close relationships to the feldspar group or to gismondine are formed by the zincoborophosphates A[ZnBP(2)O(8)] (see picture). The compounds are readily accessible under mild hydrothermal conditions (T(max)=170 degrees C) and are thermally remarkably stable (for example, 940 degrees C for A=Cs). Metalloborophosphates are a new class of compounds, which are expected to provide access to zeolite-like microporous systems.
ZUSCHRIFTEN[13] Kristallstrukturdaten von 1 [14b]: Triklin, Pi, u =12.48110(10), h = 13.9567(2), c = 21.8689(2) A, 2 = 97.3211(10), p = 98.4310(2), 7 = 114.1520(1), Z = 2, T = 20'C, pber, = 2 . [**I Diese Arbeit wurde von der Pinguin-Stiftung (Dusseldorf) gefordert
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.