[en] The tungsten-carbon multilayer system has been studied using x-ray scattering techniques as a function of multilayer period and annealing. Grazing incidence x-ray scattering shows that interatomic arrangements in the W-rich layers depend strongly on their proximity to the interface with the C-rich layers. Amorphous interface layers are stabilized by intermixing of W and C during deposition into local structures similar to those in the tungsten carbides. Further intermixing and structural relaxation in the amorphous state occurs on annealing these structures. This interatomic structural interpretation is consistent with trends in the observed x-ray optical properties