Инд. авторы:	Likhacheva A.Y., Rashchenko S.V., Seryotkin Y.V.
Заглавие:	The deformation mechanism of a pressure-induced phase transition in dehydrated analcime
Библ. ссылка:	Likhacheva A.Y., Rashchenko S.V., Seryotkin Y.V. The deformation mechanism of a pressure-induced phase transition in dehydrated analcime // Mineralogical Magazine. - 2012. - Vol.76. - Iss. 1. - P.129-142. - ISSN 0026-461X. - EISSN 1471-8022.
Внешние системы:	DOI: 10.1180/minmag.2012.076.1.129; SCOPUS: 2-s2.0-84857858186;
Реферат:	eng: The elastic and structural behaviour of dehydrated analcime in compression in a non-penetrating medium up to 3 GPa was studied in a diamond anvil cell using in situ synchrotron powder diffraction. A first-order phase transition at 0.4-0.7 GPa is accompanied by a symmetry change from monoclinic (I2/a) to pseudo-rhombohedral (R3) due to trigonalization of the aluminosilicate framework. This is due to the migration of cations to new positions close to the 6-membered rings forming the channels. The reduction of the mean aperture of the structure-forming 6- and 8-membered rings, as a result of tetrahedral tilting, leads to a 7.5% reduction in volume at the phase transition. The bulk modulus values are 38(2) GPa for the low pressure (LP) phase [fitted with a Murnaghan equation of state, K' = 4 (fixed)] and 11(4) GPa for the high pressure (HP) phase [fitted with a third-order Birch-Murnaghan equation of state, K' = 9(1)]. The elastic behaviour of the LP phase is anisotropic, with compressibilities β a :β b :β c in the ratio 1:4:2; the most compressible direction b coinciding with the orientation of empty 8-membered rings. The compressibility of the HP phase is isotropic. Trigonalization appears to be the most effective (and probably unique) mechanism of radical volume contraction for the ANA structure type. © 2012 Mineralogical Society.
Ключевые слова:	6-membered rings; phase transition; high pressure; dehydrated analcime; crystal structure; compressibility; dehydration; phase transition; elastic property; diamond anvil cell; deformation; crystal structure; compressibility; anisotropy; analcime; aluminosilicate; Crystal structure; Phase transitions; Zeolites; Phase transitions; High pressure engineering; Equations of state; Compressibility; Zeolites; High pressure engineering; Equations of state of solids; Crystal structure; Compressibility; Aluminosilicates; Structural behaviour; Pressure-induced phase transition; Murnaghan equation of state; In-situ synchrotrons; High pressure; First-order phase transitions; dehydrated analcime; Deformation mechanism; Volume contraction; Third-order; Symmetry changes; Structure type; Structural behaviour; Pressure-induced phase transition; New position; Murnaghan equation of state; Low pressures; In-situ synchrotrons; High pressure; First-order phase transitions; Elastic behaviour; Diamond-anvil cell; dehydrated analcime; Deformation mechanism; 8-membered ring; Birch-Murnaghan equation of state;
Издано:	2012
Физ. характеристика:	с.129-142