17th Group

    • Default: HF, HCl, HBr, HI, HAt

    • Molecules:

      • Neutral atoms: 1 bond is allowed.

        Exceptions:

        • 3 valence:

          • Two of the ligands should be F, Cl or oxygen; and one more atom from the 14th, 15th, 16th columns.

          • Double bonded oxygen and one any other atom from 14th, 15th, 16th columns are also accepted.

        • 5 valence:

          • Four of the ligands should be F, Cl or oxygen; and one more atom from the 14th, 15th, 16th columns. Double bonded oxygens are accepted.

        • 7 valence:

          • IF7 is accepted.

        • Halogen oxoacids:

          • HXOy, where X = Cl, Br, I or At; and y = 2, 3 or 4.

    • Ions:

      • F-, Cl-, Br-, I-, At- are accepted.

      • 1+ charged ions: 2 filled valences are necessary (bonds or radicals). If absent, implicit Hydrogen atoms added.

    • Radicals:

      • 1 Radical with 0 bond around the halogen atom is accepted.