The pressure effects on LiSbO3 have been investigated
via first-principles simulation. Multiple pressure-induced reconstructive
phase transitions between nonperovskite and perovskite states are
revealed, i.e., undergoing Pncn-to-R3c-to-P6322-to-Sb:A Pnma-to-P63/m phase transitions with increasing pressure. New nonperovskite P6322 and P63/m states, not present on experiment, can form a reversible
transformation (belonging to displacive-/quasi-reconstructive transition
in nature) with the increase and decrease of pressure, involving indirect
softening of two unstable phonon modes via symmetry analysis. The
anomalous formation of a novel Sb:A Pnma state, instead
of the Sb:B Pnma state as we commonly expected, is
also revealed and explicated by the change of Li–O and Sb–O
bonds as well as the limit of the typical tolerance factors. The dielectric
response and anomalous larger band gap under a high pressure are also
accompanied by the change of direct-to-indirect band gap. All of these
findings stimulate interest in the exploration and experimental confirmation
of such novel and diverse nonperovskite and perovskite structures
as well as their optical applications.