The superexchange interaction energy for an Fe3+-O2--Fe3+ linkage is considered for seven oxides in which Fe3+ is the only magnetic ion present, and for magnetite. The superexchange energy may be estimated from the value of TCn, where TC is the Curie temperature and n is the number of Fe3+-O2--Fe3+ inter-actions per Fe3+ ion per formula unit. The average value of TCn is 115° (range 106 to 132°). The only compounds considered are antiferromagnetic oxides in which Fe3+ ions are present in one set of crystallo-graphically equivalent positions and ferrimagnetic oxides in which Fe3+ ions are present in two different sets of crystallographically equivalent positions. No distinct correlation of superexchange energy with Fe3+-O2- distances or with the included angle in the linkages is evident. Superexchange coupling is considered only for contact distances and for included angles substantially greater than 90°.