Crystal structure solution of KMg(ND)(ND2): An ordered mixed amide/imide compound

An ordered mixed deuterated amide/imide potassium magnesium compound was synthesized with the intent of solving its structure using neutron diffraction technique with help of “ab-initio” methods. Obtained powder diffraction patterns were compatible with the orthorhombic P212121 space group, and lattice parameters a ¼ 9.8896(3) A; b ¼ 9.3496(3) A; c ¼ 3.6630(1) A, respectively. Assuming a density of 1.91 g/cm3 the investigation has allowed to locate the four constituting elements distributed in seven different sites into Wyckoff general positions 4(a), for a total of 28 atoms in the unit cell. This is the first example of crystal structure solution of a mixed imide/amide compound appearing during the dehydrogenation process of a potassium containing amide based hydrogen storage material.