ИСТИНА

https://doi.org/10.3390/IOCC2024-18275 (registering DOI) Abstract: Materials based on α-NiSO4·6H2O (NSH) (sp. gr. P41212, Z = 4) are used for lithium-ion batteries and UV filters for the solar-blind range. Their performance characteristics can be varied by introducing activator ions М. The behaviour of M in NSH depends on differences in crystallochemical characteristics of Mn+ and Ni2+ ions, the way of introducing M ions into the solution, and the growth sectors of the crystals. The goal of this work is to establish the distribution of Y3+ ions over the growth sectors of NSH:Y crystals when they are introduced into a solution in extremely small quantities (c = 10 mM). Two crystals were grown on NSH (001) plates: NSH:Y-1—perpendicular to <001> (32 g; growth duration 144 h); NSH:Y-2—parallel to <001> (269 g; growth duration 336 h). The habit (mmm) was found for NSH:Y-1, faceted by {001}, {101}, {011}, {012}, and {110} with face areas (Sface{hkl}) {101}>{011}>{012}>{001}>{110}. In the habit (mm2) of NSH:Y-2 crystals, new faces ((102), (12), and (1 )) with Sface(hkl) (101)>(012)>(102)>(011)>(001)>(1 2)>(1 )>(110) also appeared. The NSH:Y-2 crystal, by its (00) face, was at the bottom of the crystallizer during growth (uneven supply of the solution). The c, Å tetragonal crystal parameter (X-ray diffraction of powdered crystals) decreased with the decrease in Y3+ content (см, ppm—mass spectrometry), c{101}>c{102}>c{001}, consistent with crystal morphology. Defect formation can be described by the quasi-chemical reaction 0VNin’+Yim· and the composition (Ni2+1-x[])(Y3+i(x))SO4]. In the {101}-{102}-{001} series, a decrease in Y3+ content is accompanied by a decrease in the Y3+ interstitials (Yim·) and vacancies in the Ni2+ site (VNin’). The compositions of the NSH:Y growth sectors, on which the functional properties depend, are important for the application of the material in the form of plates. Funding: Ministry of Science and Higher Education of the Russian Federation, grant No. FSFZ-2024-0026. Keywords: optical materials; crystal growth; structure; composition; X-ray diffraction