Electronic structure ofMS(M=Ca,Mg,

Experimental x-ray absorption spectra were measured near the sulfur K and ${L}_{2,3}$ edges of MgS, CaS, MnS, and FeS. An agreement between full multiple scattering theoretical simulations and experiment is reached for comparatively large clusters (consisting of 9--13 shells) of sulfides with the NaCl-type structure (MgS,CaS,MnS), while a small cluster of four shells appears sufficient for the NiAs-type structure of FeS. It was shown that in the ${\mathrm{Mg}}_{1\ensuremath{-}x}{\mathrm{Fe}}_{x}\mathrm{S}$ solid solution, iron sulfide changes its structure from NiAs-type $(B8)$ to NaCl-type $(B1)$ under the influence of the MgS matrix. The partial electronic densities of unoccupied states have been calculated for MgS and CaS. It is found that the bottom of the conduction band of MgS is formed by Mg s and S s states and of CaS by Ca d states and S d, s, and p states. A special kind of hybridization has been found: it is shown that the sulfur p states are ``squeezed out'' of the energy region of the iron d states.