title: Novel sodium aluminium borohydride containing the complex anion [Al(BH4,Cl)4]-.
abstract: The synthesis of a novel alkali-metal aluminium borohydride NaAl(BH4)xCl4-x from NaBH4 and AlCl3 using a solid state metathesis reaction is described. Structure determination was carried out using synchrotron powder diffraction data and vibrational spectroscopy. An orthorhombic structure (space group Pmn2(1)) is formed which contains Na+ cations and complex [Al(BH4,Cl)4]- anions. Due to the high chlorine content (1 < or = x < or = 1.43) the hydrogen density of the borohydride is only between 2.3 and 3.5 wt.% H2 in contrast to the expected 14.6 wt.% for chlorine free NaAl(BH4)4. The decomposition of NaAl(BH4)xCl4-x is observed in the target range for desorption at about 90 degrees C by differential scanning calorimetry (DSC), in situ Raman spectroscopy and synchrotron powder X-ray diffraction. Thermogravimetric analysis (TG) shows extensive mass loss indicating the loss of H2 and B2H6 at about 90 degrees C followed by extensive weight loss in the form of chloride evaporation.
authors.affiliation: Functional Materials and Hydrides Group (Dept. 21), IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden, Germany.
authors.forename: Inge
authors.initials: I
authors.lastname: Lindemann
authors.forename: Roger Domènech
authors.initials: RD
authors.lastname: Ferrer
authors.forename: Lothar
authors.initials: L
authors.lastname: Dunsch
authors.forename: Radovan
authors.initials: R
authors.lastname: Cerný
authors.forename: Hans
authors.initials: H
authors.lastname: Hagemann
authors.forename: Vincenza
authors.initials: V
authors.lastname: D'Anna
authors.forename: Yaroslav
authors.initials: Y
authors.lastname: Filinchuk
authors.forename: Ludwig
authors.initials: L
authors.lastname: Schultz
authors.forename: Oliver
authors.initials: O
authors.lastname: Gutfleisch