Determination of orientational ordering of hydroxy groups in kulanite between 120-353 K using single-crystal X-ray diffraction

Abstract

We conducted single-crystal X-ray diffraction experiments on kulanite [Ba(Fe²⁺, Mn²⁺, Mg)₂(Al, Fe³⁺)₂(PO₄)₃(OH)₃] to investigate the potential orientational ordering of its hydroxy groups. Structural refinements showed no sign of a phase transition between 120 and 353 K. Additionally, the orientation of the hydroxy group was determined uniquely along the c-axis for the measured temperature range of 120-353 K.