Synchrotron X-ray diffraction study of ErMn2D2

ErMn2D2 deuteride has been studied by high-resolution synchrotron X-ray powder diffraction at temperatures between 150 and 298 K. Below 210 K a transformation from the hexagonal C14 Laves phase type structure (space group P63/mmc; a = 5.55357(3) Å; c = 9.05368(7) Å; T = 298 K) into the monoclinic one crystallising in the space group C2/m (a = 9.61247(9) Å; b = 5.57558(4) Å; c = 9.07102(8) Å; β = 90.5451(5)°; T = 150 K) takes place. A rather large two-phase region of coexistence of both structural modifications was observed between 185 and 205 K.