Formation ability of the perovskite-type structure in LixNa1 - xMgH3 (x = 0, 0.5 and 1.0)

Formation ability of the perovskite-type structure in LixNa1 - xMgH3 with x = 0, 0.5 and 1.0 was investigated experimentally in this study. NaMgH3 (x = 0) with the perovskite-type structure was successfully synthesised for the first time by mechanical milling alone. The diffraction peaks corresponding to the structure shift to higher angles due to the partial substitution of Na by Li in the intermediate composition (x = 0.5), while there is no evidence of the perovskite structure in LiMgH3 (x = 1.0). The experimental results can be reasonably explained from the viewpoint of the geometric restrictions on ions that are described by the Goldschmidt tolerance factors.