def bond_to_json(bond):
    """
    Return a JSON representation of `bond`.

    Parameters
    ----------
    bond : :class:`.Bond`
        The bond to serialize.

    Returns
    -------
    :class:`dict`
        A JSON representation of `bond`.

    """
    return bond.get_atom1().get_id(), bond.get_atom2().get_id(
        ), bond.get_order(), bond.get_periodicity()
