The transformation mechanism of the sodalite- to the melilite-topology: Thermal expansion and decomposition of bicchulite-type to melilite-type compounds
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Lars Peters
Abstract
The mineral bicchulite, |Ca8(OH)8|[Al8Si4O24]-SOD, has the sodalite-(SOD-)type structure. At elevated temperatures it decomposes into gehlenite, Ca2Al2SiO7 (melilite-type structure), and water (vapour). We report on the thermal expansion of two bicchulite-type compounds, the mineral bicchulite up to T = 740 K and |Ca6Eu2(OH)8|[Al10Si2O24]-SOD up to T = 1025 K. The expansion mechanism is described. Insitu X-ray powder diffraction experiments were performed to evaluate the thermal decomposition of |Ca6Eu2(OH)8|[Al10Si2O24]-SOD into 4 (Ca1.5Eu0.5)T1[T22O7] and 4 H2O, with Ti = Al or Si in a ratio of 5 : 1. A structural mechanism for the transformation from the sodalite to the melilite topology is proposed, based on geometrical considerations.
© by Oldenbourg Wissenschaftsverlag, München
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- Effect of hydrostatic pressure on the crystal structure of sodium oxalate: X-ray diffraction study and ab initio simulations
- The transformation mechanism of the sodalite- to the melilite-topology: Thermal expansion and decomposition of bicchulite-type to melilite-type compounds
- Ab initio crystal structure determination of Bi6Rh12O29 from powder diffraction data
- The crystal structure of natural 33R moissanite from Tibet
- Structure, phase transitions and dielectric properties of a new inclusion compound of bis-thiourea pyridinium nitrate salt
- Self-association and stereochemistry study of (5R)-4-methyl-5-phenyl-1,3,4-oxadiazinan-2-one
- The crystal and molecular structures of sodium and barium complexes of dibenzo-24-crown-8 ether
- Books Received
Articles in the same Issue
- Crystal structure of new lanthanide diphosphates KLnP2O7 · 2 H2O (Ln = Gd, Tb, Yb)
- Annealing effects, anomalous dielectric properties and conductivity of As-diluted lead phosphate Pb3(P1–xAsxO4)2
- Effect of hydrostatic pressure on the crystal structure of sodium oxalate: X-ray diffraction study and ab initio simulations
- The transformation mechanism of the sodalite- to the melilite-topology: Thermal expansion and decomposition of bicchulite-type to melilite-type compounds
- Ab initio crystal structure determination of Bi6Rh12O29 from powder diffraction data
- The crystal structure of natural 33R moissanite from Tibet
- Structure, phase transitions and dielectric properties of a new inclusion compound of bis-thiourea pyridinium nitrate salt
- Self-association and stereochemistry study of (5R)-4-methyl-5-phenyl-1,3,4-oxadiazinan-2-one
- The crystal and molecular structures of sodium and barium complexes of dibenzo-24-crown-8 ether
- Books Received
