M. Schlager et R. Hoppe, PREPARATION AND CRYSTAL-STRUCTURE OF K6[A L2O6] AND RB6[AL2O6], Zeitschrift fur anorganische und allgemeine Chemie, 620(5), 1994, pp. 882-887
Citations number
23
Categorie Soggetti
Chemistry Inorganic & Nuclear
Journal title
Zeitschrift fur anorganische und allgemeine Chemie
Colourless single crystals of K6[Al2O6] have been prepared from intima
te mixtures of KAlO2 and K2O (550-degrees-C, 90 d). The structure dete
rmination from four-circle diffractometer data (MoKalphaBAR, 742 I(o)(
hkl), R = 2.2%, R(w) = 2.1%) confirms the space group C2/m with Z = 2;
a = 698.25 pm, b = 1 103.54 pm, c = 646.49 pm, beta = 102.49-degrees.
Colourless single crystals of hitherto unknown Rb6[Al2O6] have been p
repared from intimate mixtures of RbAlO2 and Rb2O (520-degrees-C, 120
d). The structure determination from four-circle diffractometer data (
MoKalphaBAR, 1240 I(o)(hkl)) results in the residual values R = 7.2%,
R(w) = 4.9%; space group C2/m; a = 725.92 pm, b = 1143.33 pm, c = 678.
06 pm, beta = 104.05-degrees; Z = 2. K6[Al2O6] and Rb6[Al2O6] are isos
tructural with K6[Fe2O6]. A characteristic structure unit is the anion
[Al2O6]6- consisting of two edge-sharing [AlO4] tetrahedra. Effective
Coordination Numbers (ECoN), Mean Fictive Ionic Radii (MEFIR), the Ma
delung Part of Lattice Energy (MAPLE) and the Charge Distribution (CHA
RDI) are calculated and discussed.