15th Group
Nitrogen (N)
-     Default: NH3 
-     Molecules: -     Neutral atoms -     Implicit hydrogens are added to have 3 bonds (if nitrogen has at least 1 bond). 
 More than 3 bonds are forbidden.
 If nitrogen has 4 ligands, charge is not set, hence not accepted
 Pentavalent N is accepted in traditional form by default, but keep in mind that these forms are not correct. Use the "ylide" from of the N atom which satisfies the correct valence electron count:traditional form "ylide" form                 
-     It's possible to accept only the "ylide" form using the MoleculeGraph.setValenceCheckOptions() function. 
 
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-     Charged atoms in a molecule: -     Positive charge: -     1+: 4 bonds needed (incluing implicit hydrogens) 
-     2+: 3 bonds needed (incluing implicit hydrogens) 
-     3+: 2 bonds needed (incluing implicit hydrogens) 
-     4+: 1 bonds needed (incluing implicit hydrogens) 
-     5+: 0 bonds needed (incluing implicit hydrogens) 
-     6+ or more: not allowed 
 
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-     Negative charge: Every added negative charge decreases by one the number of possible bonds. Maximum charge accepted is -3. 
 
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-     Radical: Every added radical on these atoms decreases by one the number of bonds. Maximum three added radical is allowed. 
-     Aromatic compounds: Nitrogen may form aromatic bonds as well. 
 
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Phosphorus (P), Arsenic (As), Antimony (Sb), Bismuth (Bi)
-     Default: PH3, AsH3, SbH3, Bi 
-     Molecules: -     Neutral atoms: -     1 bond: 2 implicit Hydrogens are added. 
-     2 bond: 1 implicit Hydrogen is added. 
-     3 bond: 0 implicit Hydrogen is added. 
-     4 bond: 1 implicit Hydrogen is added. 
-     5 bond: 0 implicit Hydrogen is added. 
-     More than 5 bonds are forbidden 
 
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-     Charged atoms in a molecule: -     Positive charge: -     1+: 4 bonds are necessary (including implicit Hydrogens). 
-     2+: 3 bond is necessary (including implicit Hydrogens). 
-     3+: 2 bond is allowed. 
-     4+: 1 bond is necessary (including implicit Hydrogens). 
-     5+: 0 bond is allowed. 
-     6+ or more: not allowed 
 
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-     Negative charge: Every added negative charge decreases by one the number of possible bonds. Maximum charge accepted is -3. 
 
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-     Radical: Every added radical on these atoms decreases by one the number of bonds. Maximum three added radicals are allowed. 
-     Aromatic compounds: Phosphorus may form aromatic bonds as well. 
 
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