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Expansión térmica cero en un marco flexible y estable: tetrametilamonio cobre (I) zinc (II) cianuro
Anthony E Phillips1, Gregory J Halder, Karena W Chapman
1School of Chemistry, The University of Sydney, NSW 2006, Australia.
Journal of the American Chemical Society
|December 18, 2009
Resumen
El cobre de tetrametilamonio ((I) zinc ((II) cianuro exhibe una expansión térmica cercana a cero entre 200-400 K. Este comportamiento está relacionado con modos de vibración específicos que afectan su estructura cristalina, particularmente la coordinación de Zn y Cu.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química del estado sólido.
- La cristalografía es una técnica de cristalografía.
Sus antecedentes:
- Los materiales de expansión térmica cero son cruciales para los instrumentos de precisión.
- Las estructuras de cianuro metálico ofrecen propiedades sintonizables.
- Comprender los mecanismos de expansión térmica es clave para el diseño de materiales.
Objetivo del estudio:
- Para investigar las propiedades de expansión térmica del cobre tetrametilamonio (I) zinc (II) cianuro.
- Para dilucidar los mecanismos estructurales y vibratorios detrás de su expansión térmica cercana a cero.
- Para comparar su rendimiento con los materiales de expansión térmica cero existentes.
Principales métodos:
- Difracción de rayos X de polvo de temperatura variable.
- Difracción de rayos X de un solo cristal.
- Análisis de parámetros de desplazamiento atómico y longitudes de enlace.
Principales resultados:
- El cobre de tetrametilamonio (I) zinc (II) cianuro muestra un coeficiente de expansión térmica cercano a cero de 200 a 400 K.
- El rendimiento del material es comparable al de los principales materiales comerciales de expansión térmica cero.
- Los modos vibratorios de baja energía preservan la coordinación tetraédrica de Zn mientras distorsionan la coordinación de Cu.
Conclusiones:
- El marco de cianuro metálico estudiado es un candidato prometedor para aplicaciones de expansión térmica cero.
- Vibraciones de celosía específicas dictan la estabilidad del material a través de un rango de temperatura.
- El comportamiento distinto de las esferas de coordinación Zn y Cu es crítico para el fenómeno observado.
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