Models of Oxygen Occupancy in Lead Phosphate Apatite Pb₁₀(PO₄)₆O

High Resolution Image Download MS PowerPoint Slide Lead phosphate apatite, the parent compound of the proposed room-temperature superconductor LK-99, features a [Pb 10 (PO 4 ) 6 ] II scaffold with a charge-compensating oxide ion. This O –II occupies a 4 e site in the P 6 3 / m unit cell, with 25% probability on average. We model the occupancy of this site from substoichiometric ( x = 0) to superstoichiometric ( x = 4) regimes in Pb 10 (PO 4 ) 6 O x . Doping is predicted by adjusting the oxygen composition within the ⟨0001⟩ channel, with evidence for strong O–O correlation. This behavior introduces a sensitivity to the crystal growth and annealing conditions, with an opportunity for novel functionality to emerge.