# Why elemental carbon is solid?

Carbon with 6 protons, the first of its group, is a solid, while the very next elements, nitrogen and oxygen, are gaseous in their elemental form.

Why carbon is a solid? If it's not the molar mass that defines carbon phase (carbon's molar mass is lesser)

In pnictogen and chalcogen group only the second element, phosphorus and sulfur, is solid.

• Yet lithium, beryllium, and boron are also solids at room temperature - why not worry about them? – Jon Custer Sep 25 '15 at 0:36
• Li, Be, and B are also solids at STP, so the better question is why the transition from C to N is a major matter state change (solid to gas). – user467 Sep 25 '15 at 0:36
• related chemistry.stackexchange.com/questions/18798/… - why nitrogen is gas is better question – Mithoron Sep 25 '15 at 16:21

• The obvious follow-on question is why carbon forms large covalently-bonded complexes and not diatomic molecules. (That is, why are $\ce{C2}$ molecules not stable?) Or alternatively, why do N and O form diatomic molecules and not large covalently-bonded complexes? – R.M. Sep 25 '15 at 22:13