Structural and magnetic properties of the binary compound ScFe 2 - y (MgZn 2 -type structure) and ternary compounds Sc(Fe 0 . 9 4 Si 0 . 0 6 ) 1 . 8 6 (MgCu 2 -type structure), Sc(Fe 0 . 7 5 Si 0 . 2 5 ) 2 , Sc(Co 0 . 7 5 Si 0 . 2 5 ) 2 and Sc(Ni 0 . 7 5 Si 0 . 2 5 ) 2 (MgZn 2 -type structure), were studied. Only in the Fe based compounds does long range ferromagnetic order exist. In the pseudobinary system, Sc(Fe 1 - x Si x ) 2 - y , both the Fe moment and the Curie temperature decrease with increasing Si-concentration. This is accounted for by changes of the electronic structure. The substitution by Si has no significant influence upon the lattice parameters. In this case, however, when Sc(Fe 0 . 7 5 Si 0 . 2 5 ) 2 and Sc(Co 0 . 7 5 Si 0 . 2 5 ) 2 are compared to ScFe 2 , an anomalous increase of the electrical resistivity in the whole temperature range is observed, for the Fe compound even yielding a negative slope. Both the large resistivity values and the enhancement of the electronic specific heat (compared to ScFe 2 by a factor of three) due to the substitution are attributed to an increase of the density of states at the Fermi energy N(E F ). When comparing ScFe 2 with Sc(Fe 0 . 7 5 Si 0 . 2 5 ) 2 by Mossbauer spectroscopy, a modest reduction of the electron density at the 5 7 Fe site of ~0.1 s-electrons is observed. Thus, from the specific heat results, a significant increase of the d-density of states at E F has to be concluded.