15^th 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.

* 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

* *Negative charge:*  Every added negative charge decreases by one the number of possible bonds. Maximum charge accepted is -3.

* *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.

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

  • 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
    • Negative charge: Every added negative charge decreases by one the number of possible bonds. Maximum charge accepted is -3.
  • *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.