This article is cited in 1 paper

Dielectrics

Tolerance factor for huntite-family compounds

M. S. Molokeev^ab, S. O. Kuznetsov<sup>a

a</sup> Siberian Federal University, Krasnoyarsk
^b L. V. Kirensky Institute of Physics, Siberian Branch of the Russian Academy of Sciences, Krasnoyarsk

Abstract: 85$RM_{3}$(BO$_{3}$)$_{4}$ ($R$ is the rare-earth element (Y, La–Lu) and $M$ = Al, Sc, Cr, Fe, or Ga) compounds with the huntite structure have been analyzed. The analysis of the structures has made it possible to determine critical atomic displacements during the phase transition $R$32 $\leftrightarrow$ $P$3$_{1}$21 and establish how these critical displacements can be controlled by varying the ionic radii. A tolerance factor has been derived and its threshold value below which the structure is stable in the $R$32 phase and above it, in the distorted $P$3$_1$21 phase, has been found. The formula has been tested on more than 30 huntite-family compounds and good agreement has been obtained. Therefore, it can be used with confidence to predict new compounds. At the moment, the tolerance factor has allowed us to establish previously unknown regularities in huntites.

Keywords: huntite, tolerance factor, phase transition, crystal structure stability, crystal structure.

Received: 03.06.2020
Revised: 03.06.2020
Accepted: 26.06.2020

DOI: 10.21883/FTT.2020.11.50108.120

 English version: Physics of the Solid State, 2020, 62:12, 2058–2062

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