Default: CH₄, SiH₄, GeH₄ respectively.

Molecules:

• Neutral atoms Implicit Hydrogens are added to have 4 bonds. 5 or more bonds are forbidden.

• Charged atoms: Every added charge on these atoms (no matter it is positive or negative) decreases by one the number of possible bonds. Maximum charge accepted is ±4.

• Radical: Every added radical on these atoms decreases by one the number accepted of bonds.

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

Default: Sn

Molecules:

• Neutral atoms: Implicit Hydrogens are added to have 4 bonds (if Tin has at least 1 bond). 5 or 6 bonds are also accepted.

• Charged atoms:

  • Positive charge: Every added charge (no matter it is positive or negative) decreases by one the number of possible bonds. Maximum charge accepted is +4.

  • Negative charge: Not allowed.

• Radical: Every added radical on these atoms decreases by one the number accepted of bonds.

Ions:

• Sn²⁺ and Sn⁴⁺ are accepted.

Other:

• Sn with 2 electrons in bonds and with at least to coordinate bonds are accepted.

Default: Pb

Molecules:

• Neutral atom:

  • 1 or 2 bonds: 1 or 0 implicit hydrogen is added, respectively.

  • 3 or 4 bonds: 1 or 0 implicit hydrogen is added, respectively.

  • 5 or 6 bonds are accepted.

  • More than 6 bonds are forbidden.

• Charged atom:

  • Positive charge: Every added charge (no matter it is positive or negative) decreases by one the number of possible bonds. Maximum charge accepted is +4.

  • Negative charge: Not allowed.

• Radical: Every added radical on these atoms decreases by one the number accepted of bonds.

Ions:

• Pb²⁺ and Pb⁴⁺ are accepted.