Magnetic Susceptibility of Potassium Hexachlororhenate (IV) and Potassium Hexabromorhenate (IV) from 5° to 300°K

Abstract

The Curie points of K₂ReCl₆ and K₂ReBr₆ obtained from magnetic susceptibility measurements are 12.4±0.5° and 15.3±0.5°K, respectively, which confirm that cooperative‐type transitions observed in the heat capacities of these compounds with maxima at 11.9±0.1° and 15.2±0.1°K, respectively, represent transitions to the antiferromagnetic state. Evidence is presented that the ratios of the next nearest‐neighbor to nearest‐neighbor superexchange interactions in the two compounds are approximately equal. An estimate of the spin‐orbit coupling constants in the crystals is given and compared with other estimates.