New superconductors based on five-component transition metal oxypnictides

A review of layered five-component transition metal oxypnictides (Sr₃Sc₂Fe₂As₂O₅, Sr₄V₂Fe₂As₂O₆, Sr₄Sc₂Fe₂P₂O₆, etc.) discovered recently is presented. They constitute a new family of the so-called 32225 and 42226 phases, which are promising materials for the quest for high-temperature superconductors. The methods of synthesis, features of crystal structures, physicochemical properties as well as models of electronic structure and chemical bonding for these phases are discussed.