The ³⁵Cl, ¹²¹Sb and ¹²³Sb resonance frequencies for seventeen tetrachloro(carboxylato)antimony V compounds, RCO₂SbCl₄, are reported. The results confirm the difference in the effects of the substituent on the equatorial chlorine atoms and the axial chlorine atoms of the SbCl₄ group, previously remarked in parts I and II of this series, and this effect has been put on a more quantitative basis by correlating the observed frequencies with the pK’s of the corresponding acids.

The compounds with R = isopropyl and R = cyclopropyl both show a phase change in the region of 140 K which may correspond to reorientation of the substituent about the R-CO₂ axis.