Structural and magnetic properties of the new ternary silicide Gd3Co2.48Si1.52

► The existence of the new intermetallic Gd3Co2.48Si1.52 is reported. ► Its structure derives from the W3CoB3-type structure. ► Mixed occupancy between Co- and Si-atoms is observed for two crystallographic sites. ► A ferromagnetic transition occurs at 180 K.