Tetragonal-cubic phase transition in KGaSi2O6 synthetic leucite analogue and its probable mechanism

BELL, Anthony and HENDERSON, CMB (2019). Tetragonal-cubic phase transition in KGaSi2O6 synthetic leucite analogue and its probable mechanism. Journal of Solid State Chemistry, 284, p. 121142.

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Link to published version:: https://doi.org/10.1016/j.jssc.2019.121142


Synthetic leucite KGaSi2O6 at 298K is I41/a tetragonal and is isostructural with natural leucite (KAlSi2O6); with unit cell parameters of a ​= ​13.1099 (4), c ​= ​13.8100 (4) Å, V ​= ​2373.50 (12) Å3. With increasing temperature it undergoes a reversible, displacive phase transition from I41/a to cubic Ia3‾d; this well-studied phase transition in KAlSi2O6 occurs at ~930K. However for KGaSi2O6 it is smeared out from 673 to ~970K where it consists of a mixture of the low- and high-temperature polymorphs. The proportion of the cubic phase increases with temperature; the cubic phase volume is ~1% larger than the coexisting tetragonal polymorph. At a fixed temperature within this ‘region of coexistence’ phase proportions do not change. Such features are characteristic of 1st order, diffusionless, strain-meditated, martensitic-type phase transitions. It seems that the phase transition for synthetic KGaSi2O6 is close to being purely ferroelastic in character.

Item Type: Article
Uncontrolled Keywords: Inorganic & Nuclear Chemistry; 0302 Inorganic Chemistry; 0303 Macromolecular and Materials Chemistry; 0306 Physical Chemistry (incl. Structural)
Identification Number: https://doi.org/10.1016/j.jssc.2019.121142
Page Range: p. 121142
SWORD Depositor: Symplectic Elements
Depositing User: Symplectic Elements
Date Deposited: 29 Jan 2020 12:28
Last Modified: 17 Mar 2021 17:45
URI: https://shura.shu.ac.uk/id/eprint/25738

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