In this study, we have expanded our previous work on the Gd2(Co3-xSix) system to form the family of R2(T3-xSix) compounds with a wide range of the rare earth metals (Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er) by variation of the composition and, where necessary, the transition element (Co and Ni). We report the crystallographic and the magnetic properties of this La2Ni3-type series. The R2Co3-xSix compounds with R= Pr, Nd, Sm and Gd, undergo ferro-or ferrimagnetic transitions at TC ranging from 64 K (Nd) to 338 K (Gd) and the R2Ni3-xSix phases with R = Gd-Er display ferromagnetic order below TC from 96 K (Gd) to 7 K (Er).