The effect of divalent metal-dopants, Mg, Ca, and Zn, on the stability of LiBH(4) is studied by using the first-principles calculations and CALPHAD (CALculation of PHAse Diagram) modeling. The ground states of Mg(1/2)BH(4), Ca(1/2)BH(4), and Zn(1/2)BH(4) are shown to be I (4) over bar m2, F2dd, and I (4) over bar m2, respectively, through first-principles calculations. Positive enthalpy of mixing between Li and the alloying element is predicted, indicating unfavorable solubility of alloying elements in LiBH(4) and thus offering possibility to decrease the stability of LiBH(4). The ionic sublattice model of (Li(+), M(2+), Va)(1)(BH((4) over bar))(1) is adopted for the metal substituted LiBH(4) phase. It is observed that the addition of Mg or Zn has limited effect as the decomposition temperature is between those of LiBH(4) and M(1/2)BH(4) for Mg and Zn substitutions. LiBH(4) is destabilized with magnesium borides or LiZn(4) formation but its decomposition temperature is higher than that of M(1/2)BH(4). On the other hand, the addition of Ca significantly reduces the H(2) releasing temperature due to the formation of highly stable CaB(6). (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.