Novel Magnesium-Manganese Hydrides Prepared by the Gigapascal High Pressure Technique

Abstract

The synthesis of new ternary hydrides in the MgxMnyHz-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 Mg3MnH5∼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.