High‐pressure behavior and phase transition of jadarite, a promising B and Li mineral commodity

• Published in: Journal of the American Ceramic Society 2022-11, Vol.105 (11), p.7011-7021
• Main Authors: Comboni, Davide, Battiston, Tommaso, Rumsey, Michael S., Pagliaro, Francesco, Lotti, Paolo, Hanfland, Michael, Gatta, G. Diego
• Format: Article
• Language: English
• Subjects: Anisotropy; Atomic properties; borates; Bulk modulus; Crystallography; Deformation mechanisms; Diamond anvil cells; high pressure; Hydrostatic pressure; jadarite; lithium and boron commodity; phase transition; Phase transitions; Synchrotrons; X‐ray diffraction
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/jace.18659

The high‐pressure behavior of a natural jadarite (ideally LiNaSiB3O7(OH), a ∼ 6.76 Å, b ∼ 13.80 Å, c ∼ 7.69 Å, β = 124.09°, space group P21/c) has been studied by in situ single‐crystal and powder synchrotron X‐ray diffraction up to 20 GPa, with a diamond anvil cell and using He as a hydrostatic pressure‐transmitting fluid. Between 16.57(5) and 17.04(5) GPa, jadarite undergoes a first‐order iso‐symmetric phase transition, which is reconstructive in character, with a ΔV of approximately ‐3%. The structure of the high‐pressure polymorph was solved and refined (to R1 ∼ 4%). The isothermal bulk modulus of the low‐P polymorph of jadarite is KV0 = 55.0(5) GPa (βV0 = 0.0182(2) GPa–1), and its P‐derivative is 3.84(9). The compressional anisotropy, derived along the three main crystallographic directions, is modest, with βa0:βb0:βc0 = 1.23:1:1.23. The P‐induced deformation mechanisms at the atomic scale, which lead to phase transition, are described.