Revised crystal structure model of Li2NH by neutron powder diffraction

We performed neutron powder diffraction experiments on lithium imide Li2NH, and have proposed a revised crystal structure model. Li2NH has a face-centered cubic structure with a partially occupied hydrogen site. Of the possible crystal structure models that represent the obtained data, the model with F-43m symmetry having hydrogen atoms at the 16e site, in which only one hydrogen atom randomly occupies one of the four hydrogen positions around a nitrogen atom, is most probable. For this model, the distance between the nearest nitrogen and hydrogen atoms is 0.82(6)A, and the angle between H-N-H is 109.5deg., which are close to those of the lithium amide LiNH2, indicating that the structural circumstances around nitrogen and hydrogen are similar in Li2NH and LiNH2.

K. Ohoyama, Y. Nakamori, S. Orimo, K. Yamada · 2004