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Fulleruros alcalinos amoniacados (ND(3)) ((x) NaA(2) C(60): efectos específicos del amoníaco y superconductividad
Serena Margadonna1, Efstathios Aslanis, Kosmas Prassides
1Department of Chemistry, University of Cambridge, UK.
Journal of the American Chemical Society
|August 22, 2002
Resumen
Se determinó la estructura cristalina de los fuleruros de sodio que contienen amoníaco deuterado (ND ((3)). Los débiles enlaces de hidrógeno N-D...π influyen en el empaque y pueden explicar las propiedades superconductoras únicas.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Física del estado sólido Física del estado sólido
- Química Química es la química.
Sus antecedentes:
- Los fuleruros superconductores son una clase de materiales que exhiben propiedades electrónicas únicas.
- Comprender la estructura cristalina es crucial para elucidar los mecanismos de superconductividad.
- Estudios previos han explorado varias composiciones de fuleruro y sus estructuras.
Objetivo del estudio:
- Para determinar la estructura cristalina detallada de los fulleruros de sodio superconductores con amoníaco deuterado.
- Para investigar la disposición y la unión de los pares Na(+) -ND(3) dentro de la red de fulerido.
- Para correlacionar las características estructurales con las propiedades superconductoras observadas.
Principales métodos:
- La difracción de polvo de rayos X del sincrotrón.
- La difracción del polvo de neutrones.
- Análisis de la estructura cristalina y las posiciones atómicas.
Principales resultados:
- Los fuleruros superconductores (ND3) NaA2) C60) (A=K, Rb) exhiben una estructura cúbica centrada en la cara a bajas temperaturas.
- Los pares Na(+) -ND(3) ocupan intersticios octaédricos, mostrando desorden en dos sitios cúbicos que se interpenetran.
- Se identificaron interacciones débiles de enlace de hidrógeno N-D...π entre las unidades ND(3) y C(60).
Conclusiones:
- La estructura cristalina se caracteriza por pares desordenados de Na(+) -ND(3) en sitios octaédricos.
- El empaque intermolecular está controlado por débiles enlaces de hidrógeno N-D...π.
- Estos enlaces de hidrógeno pueden desempeñar un papel en el inusual comportamiento superconductor de estas fuleridas.
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