A systematic experimental and theoretical study of the electronic structure of stoichiometric silicides with Nb, Mo, Ta and W is presented. We have employed x-ray photoemission and bremsstrahlung isochromat spectroscopy as experimental techniques and interpreted the measured data by calculation of the density of states and matrix elements for the compounds in their real crystal structures. Use is also made of x-ray emission spectra given in the literature. The electronic structure is analysed mainly in terms of the Si s, p and metal d states in relation to the various interactions, such as the metal-metal, metal-Si and Si-Si interaction. In discussing the trends of chemical bonding, we focus on the effect of the orbital overlap, the d-band occupancy and the composition.