def _get_atom_name(atom):
    """Gets atom name. If not set ElementSymbol + Id is used.

    Args:
        atom (rdkit.Chem.rdchem.Atom): rdkit atom.

    Returns:
        str: Name of the atom.
    """
    return atom.GetProp('name') if atom.HasProp('name') else atom.GetSymbol() + str(atom.GetIdx())