Growth and Optical Properties of LixNa1–xBa12(BO3)7F4 Fluoride Borates with “Antizeolite” Structure
datasetposted on 2017-04-10, 19:18 authored by Tatyana B. Bekker, Sergey V. Rashchenko, Vladimir P. Solntsev, Alexander P. Yelisseyev, Alexander A. Kragzhda, Vladimir V. Bakakin, Yuriy V. Seryotkin, Alexander E. Kokh, Konstantin A. Kokh, Artem B. Kuznetsov
Studied LixNa1–xBa12(BO3)7F4 (P42bc) solid solution belongs to the new class of “antizeolite” borates with [Ba12(BO3)6]6+ cation pattern, which contains channels filled by anionic clusters. Optical-quality crystals were grown from the compositions with different sodium–lithium ratio. The results of Rietveld refinement based on powder data demonstrate linear increase of parameter a and unit cell volume with Na/(Na + Li) ratio in cation site. Parameter c is less sensitive to the changes in stoichiometry, which is consistent with channel topology of LixNa1–xBa12(BO3)7F4 structure. Distinctive feature of LixNa1–xBa12(BO3)7F4 crystals is their deep purple color, which is due to both hole-type and electron-type centers. Crystals are characterized by linear dichroism effect.