NONASODIUM BIS(HEXAHYDROXOALUMINATE) TRIH YDROXIDE HEXAHYDRATE (NA-9[AL(OH)(6)](2)(OH)(3)CENTER-DOT-6H(2)O) - CRYSTAL-STRUCTURE, NMR-SPECTROSCOPY AND THERMAL-BEHAVIOR

The crystal structure of the nonasodium bis(hexahydroxoaluminate) trih ydroxide hexahydrate Na-9[Al(OH)(6)](2)(OH)(3) . 6H(2)O (4.5 Na2O . Al 2O3 . 13.5 H2O) (up to now described as 3Na(2)O . Al2O3 . 6H(2)O, 4Na( 2)O . Al2O3 . 13H(2)O and [3Na(2)O . Al2O3 . 6H(2)O][xNaOH . yH(2)O], respectively) was solved. The X-ray single crystal diffraction analysi s (triclinic, space group <P(1)over bar>, a = 8.694(1) Angstrom, b = 1 1.344(2) Angstrom, c = 11.636(3) Angstrom, alpha = 74.29(2)degrees, be ta = 87.43(2)degrees, gamma = 70.66(2)degrees, Z = 2) results in a str ucture, consisting of monomeric [Al(OH)(6)](3-) aluminate anions, whic h are connected by NaO6 octahedra groups. Furthermore the structure co ntains both, two hydroxide anions only surrounded by water of crystall ization and OH groups of [Al(OH)(6)](3-) aluminate anions and a hydrox ide anion involved in three NaO6 coordination octahedra directly and m oreover connected with a water molecule by hydrogen bonding. The resul ts of Al-27 and Na-23-MAS-NMR investigations, the thermal behaviour of the compound and possible relations between the crystal structure and the conditions of coordination in the corresponding sodium aluminate solution are discussed as well.