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High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems
Published on: January 24, 2014
Estructura cristalina de la fase de alta presión del CO2 sólido
Science (New York, N.Y.)
|January 21, 1994
Resumen
La fase de alta presión del dióxido de carbono sólido (CO2) adopta una estructura ortorrómbica Cmca, pasando de la fase cúbica Pa3 alrededor de 10 gigapascals. Este cambio estructural es crucial para comprender las fuerzas intermoleculares en la condensación de CO2.
Área de la Ciencia:
- Física del estado sólido física del estado sólido.
- Ciencia de los materiales ciencia de los materiales.
- La cristalografía es una técnica de cristalografía.
Sus antecedentes:
- El dióxido de carbono (CO2) exhibe un comportamiento de fase complejo bajo presión.
- Comprender las fases de CO2 sólido es clave para comprender las interacciones intermoleculares.
Objetivo del estudio:
- Para determinar la estructura cristalina de la fase de alta presión del CO2 sólido2.
- Investigar la transición estructural de la fase de baja presión a la de alta presión.
Principales métodos:
- Se empleó la difracción de rayos X para estudiar el CO2 sólido a temperatura ambiente.
- Se analizaron los patrones de difracción del polvo para determinar la estructura cristalina.
Principales resultados:
- La fase de alta presión del CO2 fue identificada como Cmca ortorrómbico, reemplazando a la fase cúbica Pa3 a aproximadamente 10 gigapascales.
- Las dimensiones y el volumen de las células ortorrómbicas se determinaron con precisión a 11,8 gigapascals.
- Se observó un cambio de volumen cercano a cero durante la transición Pa3-Cmca.
Conclusiones:
- Las dimensiones estructurales determinadas del CO2 cristalino de alta presión son vitales para los modelos teóricos de las interacciones intermoleculares.
- Las interacciones cuádrupolo-cuádrupolo son significativas en la condensación molecular del CO2.
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