Para depositar en Docta Complutense, identifícate con tu correo @ucm.es en el SSO institucional: Haz clic en el desplegable de INICIO DE SESIÓN situado en la parte superior derecha de la pantalla. Introduce tu correo electrónico y tu contraseña de la UCM y haz clic en el botón MI CUENTA UCM, no autenticación con contraseña.
 

Caracterización de la solución sólida Na2(C03,S04) A 550°C

Loading...
Thumbnail Image

Official URL

Full text at PDC

Publication date

1996

Advisors (or tutors)

Editors

Journal Title

Journal ISSN

Volume Title

Publisher

Univ. Oviedo, Vicerrectorado de Extensión Universitaria
Citations
Google Scholar

Citation

Abstract

Although it is known that unlimited solid solution exists for the high temperature polymorphs Na2S04 (1)and α-Na2C03 , the phase relationships and the variation of crystallographic parameters for different compositions are not studied. Na2S04 has four well established modifications, but only the high temperature modification Na2S04 (1) (Pб3/mmc), stable above 237°C, forms extended solid solution series with Na2C03. At the other extreme, Na2C03 shows three polymorphs and a rather complicated transition behaviour, being the hexagonal phase α-Na2C03 (Pб3/mmc)stable at T > 489°C. In this paper, the crystallographic parameters were determined at 550°C for different solid solution compositions. The study was carried out by X ray diffraction in a high temperature powder camera. The diffraction patterns show a continuous evolution through the entire compositional range. Crystalline spacings and cell parameters decrease as the sulphate content decreases. This fact and the unusual unlimited S04=-C03= substitution can be explained by the orientational disorder of tetrahedral and triangular groups. Theoretical powder diffraction diagrams, calculated assuming this orientational and substitutional disorder, show a good fit with the experimentalresults.

Research Projects

Organizational Units

Journal Issue

Description

Unesco subjects

Keywords