Ten new title compounds were synthesized and their crystal structures refined from X-ray powder diffraction data. For the light rare earth (R = La, Ce, Pr, Nd, Sm) compounds, one of the copper sites is only partially occupied while the occupancies of this position are almost ignorable for the rare earth metals heavier than Gd including Y. The unit cell parameters show normal lanthanide contraction. The bonding energy and density of states of the La compounds are calculated. The results show that the La compound with partial Cu occupancy is more stable than that without the extra Cu.