ChemInform Abstract: Enclathration of NaB(OH)4 in the β‐Cages of Sodalite: Crystallization Kinetics and Crystal Structure.

Abstract

Enclathration of NaB(OH)4 in the β-Cages of Sodalite: Crystallization Kinetics and Crystal Structure.-White polycrystalline powder or single crystals of Na7.5(AlSiO4)6(B(OH) 4)1.5·2 H2O (I), depending on the reaction temp. and pressure, are obtained by hydrothermal synthesis from a homogeneous mixture of mullite, cristobalite, and corundum. Crystallization kinetics and the crystal structure of (I) are investigated by powder and single crystal XRD, thermal analysis, Ir spectroscopy and 29Si-and 27Al MAS NMR. The latter spectra are best suited for phase analysis and quantitative determination of the reaction progress. The formation of polycrystalline (I) starts after total dissolution of mullite and cristobalite. In the structure (cubic, P43n), the B atom is shifted out of the center of the β-cage and one of the four O atoms of the B(OH)-4 guest anion is located near the center whereas the remaining O are in the middle of its edges. -(BUHL, J.-CH.; MUNDUS, C.; LOENS, J.; HOFFMANN, W.