Abstract

Similarities in properties among pairs of metallic elements and their compounds in the lower-right quadrant of the Periodic Table have been named the ‘Knight’s Move’ relationship. Here, we have undertaken a systematic study of the only two ‘double-pairs’ of ‘Knight’s Move’ elements within this region: copper-indium/indium-bismuth and zinc-tin/tin-polonium, focussing on: metal melting points; formulas and properties of compounds; and melting points of halides and chalcogenides. On the basis of these comparisons, we conclude that the systematic evidence for ‘Knight’s Move’ relationships derives from similarities in formulas and properties of matching pairs of compounds in the same oxidation state. Physical properties, such as melting points, do not provide consistent patterns and trends and hence should not be considered as a common characteristic of this relationship.