The existence of the Mn₅Si₃ structure type for the rare earth M₅Pb₃ inter-metallic compounds has been found for all rare earths from La to Lu. Metallographic and X ray analyses confirmed this composition and this structure type. Eu and Yb metals do not form this phase but behave as bivalent elements. Lattice constants values decrease linearly with the rare earth trivalent ionic radius. Interatomic distances for the two series M₅Sn₃ and M₅Pb₃ are compared examining the case of Dy₅Sn₃ and Dy₅Pb₃. The behaviour of rare earths, including Sc and Y, with the IV A group elements over the M₅X₃ composition is briefly examined.