Formation region and hydrogen storage abilities of perovskite-type hydrides

Formation region and hydrogen desorption and absorption properties of the perovskite-type structure in LixNa1−xMgH3 with x = 0, 0.17, 0.33, 0.50 and 1.00 were studied in the present work. The experimental results are reasonably explained from the viewpoint of the geometric restrictions of ions that are described by so-called Goldschmidt tolerance factors. In NaMgH3 (x = 0), two plateau pressures of about 0.040 and 0.15 MPa were clearly detected by hydrogen pressure–composition (p–c) isotherm measurement at 673 K. Moreover, NaMgH3 can be reversibly formed in 1.0 MPa of hydrogen at 673 K, from the decomposed phase of elemental Na and Mg.