Searching for novel materials via 4f chemistry

4f chemistry studies the chemical bonding characteristics of fifteen lanthanide (Ln) elements in the periodic table and their wide applications in materials sciences and engineering, which forms the scientific fundamentals of VI periodic elements in the periodic table of elements. Orbital hybridization modes of Ln elements clarify their chemical bonding nature in all reaction systems. Wide coordination number (CN) option, ranging from 2 to 16, is the reason why Ln elements are the treasure of new materials, therefore, searching for novel materials may be well carried out via the rational design of coordination environment of central Ln cations to stabilize their variable energy states. Balance utilization of Ln elements is dependent on their coordination architecture in the crystallographic frame, Ln elements can be replaced by non-Ln elements when CN < 10, and when CN >= 10 expensive Ln elements can be replaced by those cheaper ones. (c) 2019 Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.