Correlations of the X‐Ray K‐Absorption Edge Shift (Chemical Shift) in Some Cu(II) Systems with Effective Charge and Bond Length

X‐ray absorption Cu K‐edge spectra are recorded in some Cu(II) compounds. La2CuO4, CuSO4 · 5 H2O, CuCO3 · Cu(OH)2, CuWO4, (NH4)2SO4 · CuSO4 · 6 H2O, and Cu(OH)2 and also there of pure Cu metal using a Cauchois‐type bent‐crystal X‐ray spectrograph. The X‐ray absorption chemical‐shift, ΔE, in each of the above Cu(II) compounds is measured. The chemical‐shift, ΔE, is correlated separately with each of its two governing factors, the effective charge, q, and the bond length, R, in the systems under study on the basis of the least‐squares regression analysis. Also the extent is determined to which the chemical‐shift, ΔE, is explained by each of the two factors, the effective charge, q, and the bond length, R, separately. It is also shown that the chemical‐shift, ΔE, prominently depends on the effective charge, q, and the bond length, R, i.e. q and R explain almost the total variation in chemical‐shift, ΔE, in the systems under study.