  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.
