Module Descriptors

The average molecular weight of the molecule

>>> '%.2f'%MolWt(Chem.MolFromSmiles('CC'))
'30.07'
>>> '%.2f'%MolWt(Chem.MolFromSmiles('CC'),1)
'24.02'
>>> '%.2f'%MolWt(Chem.MolFromSmiles('[NH4+].[Cl-]'))
'53.49'

The average molecular weight of the molecule ignoring hydrogens

>>> '%.2f'%HeavyAtomMolWt(Chem.MolFromSmiles('CC'))
'24.02'
>>> '%.2f'%HeavyAtomMolWt(Chem.MolFromSmiles('[NH4+].[Cl-]'))
'49.46'

The number of valence electrons the molecule has

>>> NumValenceElectrons(Chem.MolFromSmiles('CC'))
14.0
>>> NumValenceElectrons(Chem.MolFromSmiles('C(=O)O'))
18.0
>>> NumValenceElectrons(Chem.MolFromSmiles('C(=O)[O-]'))
18.0
>>> NumValenceElectrons(Chem.MolFromSmiles('C(=O)'))
12.0