When looking at the "shiny ball" models of a caffeine molecule, I notice that it terminates in 3 places with a carbon atom bonded to 3 hydrogens. But diagrams from different sources list two of them as CH3 and one of them as H3C. What's the difference? Also, what are the spacings in H3C / CH3? It looks like each bond is 120 degrees from the other bonds. But somewhere I recall hearing 105 degrees. I'm probably mixing this up with something else. Thanks in advance!