Exploration of the lithium–aluminum–silver system. Crystal and electronic structure analysis of new phases Li6.98Al4.15Ag0.87 and LiAlAg2

The lithium–aluminum–silver ternary system has been investigated and two new phases Li_6.98Al_4.15Ag_0.87 and LiAlAg₂ were characterized using both powder and single crystal X-ray diffraction techniques. These phases crystallize in the cubic system, space group (a=6.344(1), 6.3124(5) Å), they, respectively, display the Pearson's cF12- and cF16-type structural arrangements. Compared to Li₂AlAg, the only phase in the system reported so far, the structure of Li_6.98Al_4.15Ag_0.87 is disordered owing to atomic substitutions and contains a full site vacancy. Band structures and densities of states of Li_6.98Al_4.15Ag_0.87, LiAlAg₂ and Li₂AlAg have been calculated by a first principle pseudopotential method using the plane-wave basis CASTEP package.