16th Group

Oxygen (O)

  • Default: H2O

  • Molecules:

    • Neutral atom:

      • Implicit Hydrogens are added to have 2 bonds (if Oxygen has at least 1 bond).

      • More than 2 bonds are forbidden

    • Charged atom:

      • Positive charge:

        • 1+: 3 bonds are necessary (including implicit Hydrogens).

        • 2+: 4 bonds are necessary (including implicit Hydrogens).

        • 3+: 3 bonds are necessary (including implicit Hydrogens).

        • 4+: 2 bonds are necessary (including implicit Hydrogens).

        • 5+: 1 bonds are necessary (including implicit Hydrogens).

        • 6+: 0 bonds are necessary (including implicit Hydrogens).

      • Negative charge: One or two the negative charges are accepted, with one or zero ligands, respectively.

    • Radical: Every added radical on these atoms decreases by one the number of bonds. Maximum two added radical is allowed.

    • Aromatic compounds: Oxygen may form aromatic bonds as well.

Sulfur (S), Selenium (Se), Tellurium (Te), Polonium (Po)

  • Default: H2S, H2Se, H2Te, H2Po

  • Molecules:

    • Neutral atom:

      • 1 bond: 1 implicit Hydrogen is added

      • 2 bond: 0 implicit Hydrogen is added

      • 3 bond: valence error on S/Se/Te/Po atom

      • 4 bond: 0 implicit Hydrogen is added

      • 5 bond: 1 implicit Hydrogen is added

      • 6 bond: 0 implicit Hydrogen is added

      • More than 6 bonds are forbidden

    • Charged atom:

      • Positive charge:

        • Sulfur (S):

          • 1+: 3 or 5 bonds are necessary (including implicit Hydrogens).

          • 2+: 4 bonds are necessary (including implicit Hydrogens).

          • 3+: 3 bonds are necessary (including implicit Hydrogens).

          • 4+: 2 bonds are necessary (including implicit Hydrogens).

          • 5+: 1 bond is necessary (including implicit Hydrogens).

          • 6+: 0 bond is allowed.

          • 7+ or more: not allowed.

        • Selenium (Se), Tellurium (Te), Polonium (Po):

          • 1+: 1, 3 or 5 bonds are necessary (including implicit Hydrogens).

          • 2+: 0 or 4 bonds are necessary (including implicit Hydrogens).

          • 3+: 1 or 3 bonds are necessary (including implicit Hydrogens).

          • 4+: 0 or 2 bonds are necessary (including implicit Hydrogens).

          • 5+: 1 bond is necessary (including implicit Hydrogens).

          • 6+: 0 bond is allowed.

          • 7+ or more: not allowed.

      • Negative charge:

        • 1-: 1 bond accepted. (Exception: 2 double bonded oxygens and 1 more ligand connected by a single bond)

        • 2-: Zero ligand is accepted

    • Radical: Every added radical on these atoms decreases by one the number of bonds. Maximum 2 added radical is allowed.

    • Aromatic compounds: Sulfur may form aromatic bonds as well.