A new member of the aluminum hydride family, CaAlH5, is formed during the decomposition of Ca(AlH4)(2). The crystal structure of this new compound was calculated by density functional theory band-structure calculations and confirmed by X-ray powder diffraction analysis. The structure crystallizes in space group P2(1)/n (No. 14), with a = 8.3797(9) angstrom, b = 6.9293(8) angstrom, c = 9.8138(11) angstrom, beta = 93.78(1)degrees, and Z = 8.