Question

What are the criteria for a molecule to be considered an organic compound?

Answer 1

I'd say just contain any carbon-hydrogen bonds, but I don't think there is an explicit criteria.

Explanation:

It seems to me that all organic compounds have some sort of carbon-hydrogen bond. That's because anything like graphite or diamond, which are just carbon atoms themselves, are not considered organic. Gases like carbon dioxide `(CO_2)` only have `C=O` bonds, and they are also not considered organic.

In conclusion, I'd say that an organic compound must have some sort of carbon-hydrogen bond to be considered organic.

However, there are still some exceptions of course, such as urea, which has a chemical formula of `CO(NH_2)_2`. The structure of it is:

https://sciencing.com/physical-properties-urea-6369247.html

There are no `C-H` bonds here, but this compound is still considered organic. The reason for that being is that it is found in animals' bodies, especially in the urine. It is the main product that contains nitrogen during protein metabolism.