Hydrides sublattice ordering

The phase and structural relationships of the lanthanide- and actinide-hydride systems are outlined here with relevant corollary evidence to provide a suitable background and preparation for some of the more esoteric discussions to follow. Historically, the first realizations of latent structural complexities appeared with the advent of more precise neutron-diffraction measurements in conjunction with new low-temperature capabilities. X-ray studies have been of limited utility because only metal atom positions are defined and only the near-surface regions of opaque heavy-metal hydrides are sampled. However, the influence of the H sublattice ordering upon the metal lattice can be deduced. 

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