from chempy import Substance
ferricyanide = Substance.from_formula('Fe(CN)6-3')
ferricyanide.composition == {0: -3, 26: 1, 6: 6, 7: 6}
True
print(ferricyanide.unicode_name)
Fe(CN)₆³⁻
print(ferricyanide.latex_name + ", " + ferricyanide.html_name)
Fe(CN)_{6}^{3-}, Fe(CN)<sub>6</sub><sup>3-</sup>
print('%.3f' % ferricyanide.mass)
211.955
In composition, the atomic numbers (and 0 for charge) is used as keys and the count of each kind became respective value.