Vanadium trimers randomly aligned along the c-axis direction in layered LiVO2

Herein, we discuss the identification of vanadium trimers in layered LiVO2 and its sulfide analog of LiVS2 with two-dimensional triangular lattices. Our comprehensive structural studies using synchrotron X-ray diffraction experiments clarified that vanadium trimers are randomly aligned along the c-axis direction in LiVO2, while the long-range ordering of vanadium trimers along the c-axis direction appears in LiVS2. Our results solve the longstanding issue of cluster patterns in LiVO2 and provide an experimental basis for identifying the mechanism of trimer formation.