Silicon binary phase

Since the first synthesis of silicon monoxide by Potter 1905, the chemical state and atomic structure of this amorphous solid have been discussed controversially. The known binary phase diagrams of silicon and oxygen that... 

Kub] Kubasehewski, O., Iron-Silicon in Iron-binary Phase Diagrams , Springer Verlag, Berlin, 136-139 (1982) (Phase Diagram, Review, 23)... 

Silicon, as the heavier homolog of carbon, is fourfold coordinated in its compounds in most cases. This is, for example, reflected by the chemistry of silicates [1]. In these naturally occurring compounds, the silicon atoms are almost exclusively found in Si04-coordination. The situation is similar for synthetic solids, such as extended binary phases like pure silica zeolite-type frameworks [2], SiS2, SiC or Si3N4, and related more complex ternary and multinary solids [3], This is also valid for molecular silicon halides, hydrides, and metal organic (e.g., silicon alkoxides) as well as organometaUic silicon compounds [3, 4],... 

The study of inverse adhesive emulsions has revealed the same features as direct emulsions [112,113]. Here again, it was shown that adhesion is favored when the surfactant becomes less soluble in the continuous phase [113]. This can be tested experimentally by using binary mixtures of oils, one in which the surfactant is soluble and another one in which the surfactant is insoluble. For example, water droplets can be stabilized in mineral oil by sorbitan monooleate (Span 80). This surfactant is soluble in dodecane whereas it is not in silicon oil. The affinity of the surfactant for the organic solvent can be tuned by mixing dodecane and silicon oil. As shown in Fig. 2.38, the energy of adhesion between water droplets strongly varies as the ratio of the mixture is changed. A sharp rise is noted as the surfactant... 

Like carbon and silicon, and to a lesser extent, germanium and tin. lead forms binary compounds with metals, such us NajPh and Nu Pb.i. These materials are essentially salt-like, ami contain polypluinbide anions. They are of theoretical interest, because they are intermediate m character between stoichiometric ctimpounds idaltonidc compounds) and intermediate phases. The two compounds cited dissolve in liquid ammonia, electrolyze in such solutions to give the metals, and apparently form ions such as [Fh-r 1J and (Ph.,)4- which readily form amine complexes. 

Fig. 3.8. Backscattered electron image of the transition zone between cobalt and silicon after annealing at 800°C for 230400 s (64 h) in vacuum.264 The microstructure reveals all the phases available on the equilibrium phase diagram of the Co-Si binary system. A continuous crack is seen between Co and C02SL Photograph kindly provided by Dr. A.A. Kodentsov. Reprinted with permission from Elsevier Science.

Cai4Sii9 is an overlooked phase in the binary system with nearly an even number of (3b)- and (2b)-Si atoms per formula unit [31, 48]. It contains a novel two dimensional polyanion of silicon which is displayed in Fig. 6a. The central unit is a 3,3,3-barrelane Sin which is linked via six Si3 bridges to six neighboring barrelanes. The whole polyanion contains seven layers of silicon atoms and has a width of ca. 900 pm. The barrelane part is shown in Fig. 6b with its trigonal planar (3b)-silicon atoms. The calcium atoms are distributed not only between but also inside the layers. 

The principles of the epitaxial growth can be described using the phase diagram of the binary system Si-Sn as an example (Fig. 9.1). The upper curve represents the so-called liquidus . At point A, the system is a liquid mixture of Sn solvent and Si, at temperature Ta with a composition A"a the solution is saturated with silicon. 

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