Silicon carbide, SiC, is a covalent network solid with a structur...

Question

Silicon carbide, SiC, is a covalent network solid with a structure
similar to that of diamond. Sketch a small portion of
the SiC structure.

Accepted Answer

Hello. In this problem, we are told that one form of silicon dioxide known as alpha court is a global network solid with a tribunal crystal system. Each silicon atom is bonded to four oxygen atoms and each oxygen is bonded to silicon atoms forming a corner sharing silicon tetroxide tetrahedron. Were asked to draw a partial structure of silicon dioxide. Recall that silicon is in group four A. It has four valence electrons. Trying to acquire eight. Then that means silicon typically forms four bonds to acquire an octet, oxygen is in group six A. It has six valence electrons and so it needs two more to get to eight. So it typically forms two bonds. We see that that's what's described in the problem statement. We have silicon bonded to four oxygen atoms and oxygen is bonded to two silicon atoms. So let's begin by looking at the answers that have been provided to see if they follow what was given in the problem statement. So in the first one, we see that the silicon is bonded to two oxygen's. It's not bonded to four. So that then means that A is not the correct answer. And then if we look at B, we have silicon forming for bonds with oxygen. But if we look at the oxygen, we see that oxygen's all do not form two bonds with silicon. So we have oxygen to form one bond of silicon and one bond with oxygen. So that then eliminates B. If we now look at sea, we have silicon bonded to for oxygen's and we have oxygen bonded to two silicones. In addition, we see that we have these corner sharing silicon tetroxide tetrahedron. And so answer C. Meets all the requirements set out for silicon dioxide, um Also known as alpha quartz for completeness. Let's go on and consider D. So indeed we have. Then silicon again does form Bond with four oxygen's. But again, we see that some of the oxygen's only form a single bond of silicon. They form one bond with silicon and one bond with oxygen. And so that eliminates D from consideration as well. So see then is the correct answer where we have each silicon atom bonded to four oxygen atoms and each oxygen bonded to silicon atoms. And they form a corner sharing silicon tetroxide tetrahedron. Thanks for watching. Hope. This helped.

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