Molecular Complexes of Emerging Tetravalent Rare‐Earth Metals

Abstract

Exploring new oxidation state of elements is an important and challenging issue. Rare‐earth elements all exhibit the stable +3 oxidation state, while the +2 oxidation state is accessible except radioactive Pm. However, until 2019, only cerium has the +4 oxidation state in molecular complexes. Since 2019, four Tb(IV) and Pr(IV) molecular complexes have been successful prepared and will open a new avenue for the development of tetravalent rare‐earth chemistry. This emerging topic briefly describes the recent advances and prospects of the tetravalent rare‐earth chemistry.