The Missing Tb₂O₂NCN Compound: Synthesis, Characterization, and Luminescent Properties

Advances in the synthetic methods often lead to the discovery of new materials, and nitridocarbonates based on the NCN 2− anion are no exception. Recent momentum in preparation processes and improved understanding of the chemistry of these compounds has resulted in many “missing compounds” now being accessible. Accordingly, the synthesis of the terbium oxide carbodiimide Tb 2 O 2 NCN is reported herein, one of the missing members in the family of rare‐earth compounds with the general formula Ln 2 O 2 NCN. It is prepared via a solid‐state metathesis reaction at 600 °C between TbOCl and Li 2 NCN, and its structure is determined from powder X‐ray diffraction data to crystallize isotypically to the Ln 2 O 2 NCN family with Ln = Ce–Yb (except for promethium) in the trigonal space group. The crystal structure is best described as alternating layers of NCN 2− anions and Tb 2 O 2 2+ layers along the c ‐axis. Photoluminescence measurements reveal a green emission at room temperature.