Electronic Structures from X-Ray Spectra. II. Mostly ClO3 − and ClO4−

New measurements of the chlorine $\mathrm{K\alpha }$ and $\mathrm{K\beta }$ x‐ray emission spectra from ClO₃ − and ClO₄ − ions are reported. The $\mathrm{K\alpha }$ energy shifts give chlorine net $\text{3s}$ , $\text{3p}$ occupations of 5.5 and 4.9 in ClO₃ − and ClO₄ − respectively. Three lines are observed in the $K$ spectrum of ClO₃ −, two in the spectrum of ClO₄ −. These emission features are interpreted as transitions from MO's and particular assignments are made. Chlorine $\text{3p}$ contributions to these orbitals are deduced and the ionization‐potential differences are estimated. The widths of x‐ray spectral features are considered. Evidence is presented which suggests that the argon compound isoelectronic with ClO₄ − is unstable; that with ClO₃ − is stable. A relationship between heats of formation and x‐ray ionization thresholds is discussed.