Structural features have been identified for microcrystalline silicon carbide (µc-SiC), and also for the amorphous analog (a-SiC) within the framework of molecular dynamics by the use of the empirical Tersoff potential. Detailed analyses have been performed for µc-SiC on the crystallite, grain boundaries, and amorphous matrix. The amorphous matrix in µc-SiC is more ordered than the amorphous structure in a-SiC. Careful studies have been made of the state densities in the two materials on the basis of an sp3s* tight-binding scheme. A possible mechanism has been proposed for the effects of homopolar bonds and other coordination defects on the electronic states and cohesion. The results are compared with those obtained by other researchers.