@patg7950 Well, I had to get to class, so I couldn’t follow up my answer. :P
As you said, it can make up to 4 covalent bonds. Carbon structures come in several varieties as you probably know [graphite, diamond, and fullerene (which of course, is a sub category with more differentiation)]
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Graphite is made of weakly bonded layers of strongly bonded “sheets” of carbon in a hexagonal cell structure. My understanding is that each atom is double bonded once, and single bonded twice to achieve this formation.
Diamond is made of a rigid, structure in which one “cell” looks like a tetrahedral carbon structure, where the central carbon is bonded to four others, and all carbon atoms are evenly spaced.
Fullerene covers carbon formations, such as carbon nanotubes (basically a sheet of graphite connected to itself, or spherical fullerenes (buckyballs) (Yes, from Buckminster Fuller) whose structures contain a mix of hexagonal and pentagonal rings.
Lastly, amorphous carbon (like charcoal or soot) has no regular structure.
I think there might be at least one other structure, but I’m forgetting.