# Handling Explicit Hs

When Hs are removed from a molecule, all Hs are removed except:

1. Hs where an isotope has been set
2. Hs that have a wedged or dashed bond to them
3. Hs bonded to atoms with tetrahedral stereochemistry set ("Chiral Hs")
4. Hs bonded to atoms with three (or more) ring bonds that are not simply protonated
5. Hs bonded to atoms in a non-default valence state that are not simply protonated 

For the above, the definition of "simply protonated" is an atom with charge = +1 and
a valence that is one higher than the default.

Here are some examples

| Original | Standardized | Notes |
|----------|-------------|-------|
| [[/images/other/Hs1.png]] | [[/images/other/Hs2.png]] |  | 
| [[/images/other/Hs3.png]] | [[/images/other/Hs4.png]] |  | 
| [[/images/other/Hs5.png]] | [[/images/other/Hs6.png]] |  | 
| [[/images/other/Hs7.png]] | [[/images/other/Hs8.png]] | Only noncyclic bond is to a chiral center |