Thursday, November 29, 2012

Synthesis and Crystal Structure of Cubic Ca16Si17N34

Synthesis and Crystal Structure of Cubic Ca16Si17N34

Abstract Image
Paulina Levario

Since the late 1960s, the exact structure of cubic calcium silicon nitride has been a source of debate. This paper offers evidence that the cubic phase CaSiN2 described in the literature is actually Ca16Si17N34. Presented here is a method for synthesizing single crystals of cubic-calcium silicon nitride from calcium nitride and elemental silicon under flowing nitrogen at 1500 °C. The colorless millimeter-sized crystals of Ca16Si17N34 with a refractive index (n25) = 1.590 were found to be cubic (a = 14.8882 Å) and belong to the space groupF4̅3m (216). The synthesis of bulk, powdered cubic-Ca16Si17N34 from calcium cyanamide and silicon is also discussed. Ca16Si17N34 is a relatively air-stable refractory ceramic. In contrast to the orthorhombic phase of CaSiN2, in which Ca2+ sits in octahedral sites, this cubic phase has Ca2+ in cubic sites that makes it an interesting host for new phosphors and gives rise to unique crystal field splitting.

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Synthesis and Crystal Structure of Cubic Ca16Si17N34

Sandra M. Hick, Mattheu I. Miller, Richard B. Kaner, and Richard G. Blair
Inorganic Chemistry Article ASAP
DOI: 10.1021/ic300627q
Publication Date (Web): November 16, 2012
Copyright © 2012 American Chemical Society

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¿Cómo es la cuarta dimensión? Mientras se daba en clase el tema "simetría molecular", llegamos al tema de la cuarta dimensión....