polarity_number

skfp.descriptors.polarity_number(mol: Mol, distance_matrix: ndarray | None = None, carbon_only: bool = False) → int

Polarity Number.

Calculates the Polarity Number [1] [2], defined as the total number of unordered pairs of vertices (atoms) in a molecular graph that are separated by a graph distance of exactly 3. It provides information about the structural connectivity of a molecule.

Parameters:

• mol (RDKit Mol object) – The molecule for which the Polarity Number is to be calculated.

• distance_matrix (np.ndarray, optional) – Precomputed distance matrix. If not provided, it will be calculated using RDKit.

• carbon_only (bool, default=False) – Whether to consider only carbon-carbon distances. If True, the distance matrix will be filtered to include only rows and columns corresponding to carbon atoms.

References

[1]

Wiener, Harry. “Structural Determination of Paraffin Boiling Points” Journal of the American Chemical Society 69.1 (1947): 17-20.

[2]

Liu, Muhuo, and Bolian Liu. “On the Wiener Polarity Index” MATCH Commun. Math. Comput. Chem 66.1 (2011): 293-304.

Examples

>>> from rdkit.Chem import MolFromSmiles
>>> from skfp.descriptors import polarity_number
>>> mol = MolFromSmiles("C1=CC=CC=C1")  # Benzene
>>> polarity_number(mol)
3