ZrMn2H3 is a Laves Phase intermetallic hydride with interesting materials properties - unlike most Laves Phases, the parent alloy ZrMn2 is not a line phase but has a wide range of inhomogeneity. ZrMnx maintains the C14 (P63/mmc) structure with only small variations in lattice parameters from 1.8<x<3.8; other materials properties, such as hydriding thermodynamics and magnetism are, however, highly sensitive to Mn content. It has been shown that below 230 K, stoichiometric ZrMn2D3 undergoes an unidentified order-disorder transition; it is probable that ZrMn2+xD3 will also undergo a low T transition which may differ from that of the stoichiometric compound, and may even vary with the manganese content. We propose to investigate the low T structures of ZrMn2D3 and a series of ZrMn2+xD3 compounds to investigate temperature-induced phase transitions and unambiguously identify D atom positions.