Dump content of :attr:`Molecule.properties` to a JSON dictionary.

        Parameters
        ----------
        filepath : :class:`str`
           The filepath for the dumped file. If :class:`None`, the file is
           dumped localy with :attr:`molecule_id` as filename.
           (defualt=None)

        molecular : :class:`bool`
            If False, dump only the content of :attr:`Molecule.properties`,
            if True, dump all the information about :class:`Molecule`.

        Returns
        -------
        None : :class:`NoneType`

def dump_properties_json(self, filepath=None, molecular=False, **kwargs):
        """
        Dump content of :attr:`Molecule.properties` to a JSON dictionary.

        Parameters
        ----------
        filepath : :class:`str`
           The filepath for the dumped file. If :class:`None`, the file is
           dumped localy with :attr:`molecule_id` as filename.
           (defualt=None)

        molecular : :class:`bool`
            If False, dump only the content of :attr:`Molecule.properties`,
            if True, dump all the information about :class:`Molecule`.

        Returns
        -------
        None : :class:`NoneType`

        """
        # We pass a copy of the properties dictionary.
        dict_obj = deepcopy(self.properties)
        # If molecular data is also required we update the dictionary.
        if molecular is True:
            dict_obj.update(self.mol)
        # If no filepath is provided we create one.
        if filepath is None:
            filepath = "_".join(
                (str(self.parent_system), str(self.molecule_id))
            )
            filepath = '/'.join((os.getcwd(), filepath))
        # Dump the dictionary to json file.
        self._Output.dump2json(dict_obj, filepath, default=to_list, **kwargs)