VALENCES

Default number of bonds to each element, used by Builder.add_hydrogens.

VALENCES={
    "H": 1,
    "B": 3,
    "C": 4,
    "N": 3,
    "O": 2,
    "F": 1,
    "Si": 4,
    "P": 3,
    "S": 2,
    "Cl": 1,
    "Br": 1,
    "I": 1,
}