Novel magnesium-manganese hydrides prepared by the gigapascal high pressure technique

摘要

The synthesis of new ternary hydrides in the Mg{sub}xMn{sub}yH{sub}z-system (x:y 1, 2, 3, or 4:1) was investigated by applying high pressures. Powder mixtures of magnesium hydride and manganese were pressed into a pellet and compressed at a pressure of 6 gigapascal by using a machine with 6-8 multi-anvils during heating up to 873 K. The resultant samples were studied by means of X-ray powder diffraction, thermogravimetry and differential thermal analysis. A new hydride of Mg{sub}3MnH{sub}(5～6) containing at least 2.4 mass% hydrogen was found, which can be indexed as a monoclinic structure with cell parameters of a = 0.8827(2)nm, b = 0.4657(2)nm, c= 0.4676(2)nm and β= 105.72(2)°. The desorption temperature of hydrogen was determined as 603 K.