Comment on Structural Stability and Electronic Structure for   Li$_3$AlH$_6$
  Density functional calculations of the electronic structure are used to elucidate the bonding of Li$_3$AlH$_6$. It is found that this material is best described as ionic, and in particular that the [AlH$_6$]$^{3-}$ units are not reasonably viewed as substantially covalent. 
D.J. Singh