Abstract: | The Crystal Structure of the Sodium Oxohydroxoaluminate Hydrate Na2Al2O3(OH)2] · 1.5 H2O The crystal structure of the sodium oxohydroxoaluminate hydrate Na2Al2O3(OH)2] ·s 1.5 H2O (up to now described as Na2O · Al2O3 · 2.5 H2O and Na2O · Al2O3 · 3 H2O, respectively) was solved. The X-ray single crystal diffraction analysis (tetragonal, space group P-421m, a = 10.522(1) Å, c = 5.330(1) Å, Z = 4) results in a polymeric layered structure, consisting of AlO3/2(OH) tetrahedral groups. Between these layers the Na+ ions are situated, which form tetrameric groups of face-linked NaO6 octahedra. The involved O2? ions are due to Al? O? Al bridges, Al? OH groups and water of crystallization. 27Al and 23Na MAS NMR investigations confirm the crystal structure analysis. The relations between the crystallization behaviour of the compound and the constitution of the aluminate anions in the corresponding sodium aluminate solution and in the solid, respectively, are discussed. |