Extended X-ray absorption fine structure (EXAFS) studies of the amorphous chromium sulfide, CrS₃, the amorphous chromium selenide, CrSe₃, and the crystalline vanadium sulfide model compound, VS₄, have been carried out at both the metal and chalcogen K edges. Structural models based on the distances and coordination numbers obtained from the analysis of these data are presented for CrS₃ and CrSe₃. In CrS₃, chromium is surrounded by an average of six sulfurs at 2.35 Å. The sulfur-edge data can be fitted by two shells containing two chromium neighbours at 2.34 Å and one sulfur neighbour at 2.03 Å. The results of sulfur K-edge absorption spectroscopy of CrS₃, Cr₂S₃, VS₄ and α-S suggest that all sulfur is found in one oxidation state, S^–1, and we formulate CrS₃ as Cr^III(S^–1₂)_1.5. The edge shift, ΔE, of the chromium K edge of CrS₃(ΔE= 6.37 eV) relative to chromium metal, is close to that of Cr₂S₃(ΔE= 6.88 eV), supporting the assignment of the oxidation state of chromium as III. In CrSe₃, chromium is surrounded by an average of six seleniums at a distance of 2.50 Å. Each selenium has an average of two chromium neighbours at 2.45 Å, and 0.67 of a selenium neighbour at 2.34 Å. We formulate CrSe₃ as Cr^IV(Se^–1₂)Se^–II. The chromium K-edge shift of CrSe₃(ΔE= 5.79 eV) is large for a chromium selenide and provides further evidence for the assignment of the oxidation state of chromium in CrSe₃ as IV. The magnetic moments per chromium measured at room temperature were 1.74(3)µ_B for CrS₃ and 2.62(3)µ_B for CrSe₃, supporting the assignment of different oxidation states to chromium in the two materials.