  Sc$_3$CoC$_4$ is the only superconductor in the group of the isotypic
carbides Sc$_3M$C$_4$ ($M$ = Mn, Fe, Ru, Os, Co, Rh, Ir, Ni), rendering it into
an ideal benchmark system to systematically study the prerequisites and
mechanism of superconductivity in such quasi one-dimensional structures. To
investigate the isotope effect, the substitution series
Sc$_3$Co($^{12}$C$_{1-x}$$^{13}$C$_x$)$_4$ with $x$ = 0, 0.5 and 1 was
synthesized by arc melting. The sample homogeneity was confirmed by powder
X-ray diffraction and NMR spectroscopy. The resulting isotope coefficient based
on magnetization studies on polycrystalline samples and electrical resistivity
measurements on single crystals of $\alpha$ = 0.58 lies close to the value of
0.5 predicted by BCS theory.
