In other words, some C atoms form C�CC�CC SRO during solidification. The bond length of C�CSi remains 1.85? throughout solidification, which is very Perifosine mw close to the results of Kaloyeros et al. [19] and Pascarelli et al. [20] as measured by extended X-ray absorption fine structure. The bond length of the Si�CSi bond gradually decreases from 2.5? to 2.35? with temperature decrease. At 100K, the bond length of Si�CSi is close to that of the crystal Si at 2.36?, which indicates that some Si atoms form Si�CSi�CSi SRO.Figure 1The evolution of the RDF with decreased temperature. ((a) gTol(r); (b) gC�CC(r); (c) gC�CSi(r); (d) gSi�CSi(r)).3.2. Coordination Number (CN)The CN is the average number of nearest-neighboring atoms used to describe the degree of tightness of atomic arrangement.

For a multicomponent system, such a number must be separately defined for each type of atom pair. Thus, the partial coordination is indicated by the areas under the first peak (up to the minimum) in the partial RDF (PRDF) g����(r). Figure 2 shows the average CN of C and Si atoms versus the temperature.Figure 2The average CN of Si and C with decreased temperature.Figure 2 shows that the average CN of carbon or silicon atoms is <4 at 4500K. The CN of Si and C increases with decreased temperature. At <1500K, the CNs of Si and C are stable at 4.01 and 3.72, respectively. The change in the CN of silicon and carbon atoms during solidification is small, and the average CN ofSiC is 3.87 at the end of solidification, which is close to the experiment results 3.99 [20] and 3.94 [21].

In liquid SiC, neither the high-density phase of silicon (the CNs are 5.8�C6.0 for pure liquid silicon [19] and 6.0 [18] for silicon in liquid SiGe) nor the liquid-liquid phase transformation occurs during liquid silicon solidification [21]. The CN of pure liquid carbon is 2.8-2.9 [19], which is lower than that of SiC.Table 1 shows the positions of the first three peaks of the RDF and the average of corresponding partial CNs at 100K.Table 1Position of the first three peaks of RDF and the average of corresponding partial CN z at 100K.In Table 1, 1.68 silicon and 2.33 carbon atoms on average are bonded to each silicon atom, that is, zSi�CSi = 1.68 and zSi�CC = 2.33, whereas 1.39 carbon and 2.33 silicon atoms are bonded to each carbon atom, that is, zC�CC = 1.39 and zC�CSi = 2.33. In total, silicon has 4.

01 nearest neighbors (zSi = 4.01) and carbon has 3.72 nearest neighbors (zC = 3.72). The final structure of quenched SiC cannot be described AV-951 as a tetrahedral network because most carbon atoms are threefold coordinated.3.3. Angular Distribution Function (ADF)The ADF can be used to describe the statistical average of angles formed with neighboring atoms. Figure 3 shows the relationship between the ADF and temperature. Figure 3 shows that the maximum peak of the ADF is located at 120��, which indicates that many threefold coordinated atoms exist in the system.