Silicon, thermodynamic properties

For cubic crystals, which include silicon, properties described by other than a zero- or a second-rank tensor are anisotropic (17). Thus, in principle, whether or not a particular property is anisotropic can be predicted. There are some properties, however, for which the tensor rank is not known. In addition, in very thin crystal sections, the crystal may have two-dimensional characteristics and exhibit a different symmetry from the bulk, three-dimensional crystal (18). Table 4 is a listing of various isotropic and anisotropic silicon properties. Table 5 gives values for the more common physical properties and for some of the thermodynamic properties. Figure 5 shows some thermal properties. 

There have been numerous experimental as well as theoretical studies dealing with the structural and thermochemical properties of cationic silicon hydrides, Si Hm+ , and a detailed discussion of these species would certainly exceed the limited space available. We will therefore confine ourselves to the discussion of only a few exemplary cases. For further information on Si-ion thermochemistry the reader is referred to several reviews on the experimental2-4 as well as computational5 determination of thermodynamic properties of silicon-containing ions. 

No systematic experimental studies on thermodynamic properties of five-membered heterocycles with three or more heteroatoms and at least one tetracoordinated silicon atom were reported. The aromaticity of the fully conjugated germadisiloleanion 21, a heavy congener of the cyclopentadienyl anion, was deduced mainly from its NMR spectroscopic and structural parameters <2005JA13143>. 

L. V. Gurvich, I. V. Veyts, and C. B. Alcock, Thermodynamic Properties of Individual Substances, Vol. 2 Elements Carbon, Silicon, Germanium, Tin, Lead, and Their Compounds, Pt. 1 Methods and Computation, Hemisphere, New York, 1991. 

The physical properties of silicon tetrahalides are listed in Table 1 those of the halohydrides are listed in Table 2. A more complex review of the physical properties of these chemicals is available (2). Detailed lists of properties of the colorless fuming liquids, silicon tetrachloride and trichlorosilane, are given in Table 3. A review of the physical and thermodynamic properties of silicon tetrachloride is given in Reference 3. 

Yaws, C. L. and Others, "Physical and Thermodynamic Properties of Silicon Tetrachloride , Solid State Techn., 22 (No.2), 65 (February, 1979). 

Desai, P.D., Thermodynamic Properties of Iron and Silicon. Journal of Physical and Chemical Reference Data, 1986.15(3) p. 967-983. 

The experiments were done under the following conditions 7 g of Sn (purity 5N), 2h of growth, 0.5°C min-1 cooling rate. Since the amount of silicon incorporated in the melt increases with the temperature, it is possible to grow thick epitaxial layers. However, for low-temperatures (700-800°C), incorporation of silicon is low and limits the kinetics of growth. At this temperature range, thermodynamic properties of metallic alloys can increase the kinetics (see Sect. 9.6). 

The assessed kinetic database covers the same system as in the thermochemical database and is schematically shown in Figs. 13.11 and 13.12, respectively. Diffusivities of Al, As, B, C, Fe, N, O, P, and Sb in both solid and liquid silicon have been extensively investigated. The assessment of the impurity diffusivity is basically the same as for the thermodynamic properties. Experimental data were first collected from the literature. Then, each piece of selected experimental information was given a certain weight factor by the assessor. The weight factor could be changed until a satisfactory description of the majority of the selected experimental data was reproduced. 

The assessed thermodynamic properties of liquid and solid Si-based solution can be directly applied to evaluate the influence of third element on the solubility of the main impurity in silicon melt. For example, the effect of the impurity element on the solubility of C in pure Si melt can be evaluated by the following equation ... 

In the papers [41,42] the thermodynamic properties of polyethylene glycol PEG 4000 and silicone oil DC 550 of different quantities deposited on the heterogeneous surface of carbosils were investigated. The surfaces of tested adsorbents were similar to those described by the patch-wise model including local energetic heterogenities. 

Tomaszkiewicz, Susman, Volin, and O Hare in [94TOM/SUS] measured the enthalpy of formation of SiSe2(cr) and thoroughly reviewed the thermodynamic properties of silicon selenides. No new experimental information is available and in general the values reported in [94TOM/SUS] are accepted by the review. Thermodynamic information is available for SiSc2(cr) and SiSe(g). 

PolydialkyMoxanes represent a group of flexible macionK>te iiles that have not only interesting low and high temperature materials p-operties (silicones), but they may also show special electronic properties. The simplest member of the hcanologous series is polydimethylsiloxane. It exhibits no condis pha% ami s ms to have normal thermodynamic properties On samples of crystallinity varying... 

Chr] Chraska, R, McLellan, R.B., Thermodynamic Properties of Carbon in BCC and FCC Iron-Silicon-Carbon Solid Solutions , Acta Metall, 19, 1219-1225 (1971) (Experimental, Phase Diagram, Phase Relations, Calculation, Thermodyn., 31)... 

Sharma RA, Seefurth RN (1976) Thermodynamic properties of the lithium-silicon system. J Electrochem Soc 123 1763-1768... 

In a later paper Pollard et al discuss the use of the flame ionization detector in the gas chromatography of tetramethyltin, trimethylethyltin, dimethyldiethyltin, methyltriethyltin and tetra-ethyltin. They discuss the unusual sensitivity characteristic of the chromatography of these compounds and present and correlate specific dynamic properties obtained and various thermodynamic properties obtained on columns comprising 15% Silicone oil E301 (mol.wt, 700,000) on Celite (James and Martin ) (treated by dry sieving to mesh 36-60, washing with concentrated hydrochloric acid, methanol and distilled water, followed by drying at 300°C). 

Models for the Calculation of Thermodynamic Properties of Crystalline Silicon under Strain. 

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