Die Kristallstruktur von Bariumamid,Ba(NH2)2

The Crystal Structure of Barium Amide, Ba(NH₂)₂ Single crystals of barium amide can be obtained by the reaction of barium metal with ammonia during long times. At ? 70° C Ba reacts with the solvent very slowly. The resulting amide then is well crystallized. Crystals can also be grown at 125° C in a temperature grakient. In both cases 3 to 4 months are necessary to get crystals of about 0.1 mm in diameter. Barium amide is monoclinic a = 8.951 Å, b = 12.67 Å, c = 7.037 Å, und β = 123.5° with 8 formula units. The space group is Cc. All atoms occupy the general position. The structure of Ba(NH₂)₂ shows two different Ba atoms with respect to their surrounding. One of them is coordinated irregularly by 8 amide ions, the other by 7 amide ions. The nitrogen atoms have 11 neighbours to each other. This means, that they are relatively close packed. Barium amide has a coorkination type structure, whereas the low symmetry of the arrangement of the different ions may be explained by the dipole chracter of the anion, and by packing effects.