 Attributes defined for atoms include "I=" for isotope mass number, "charge=" for formal charge, "fcharge" for partial charge, "s=" for stereochemistry, and "spin=" for radicals (singlet, doublet, triplet).A formal charge of codice_7 can be abbreviated as codice_8, and vice versa for negative charges; codice_9 and codice_10 is additionally recognized as -1 or +1 charges.codice_11 is a shorthand for codice_12.