def fixMono(SpGrp):
    """fixes b-unique monoclinics in e.g. P 1 2/1c 1 --> P 21/c """
    Flds = SpGrp.split()
    if len(Flds) == 4:
        if Flds[2] != '1':
            return '%s %s' % (Flds[0], Flds[2])
        else:
            return None
    else:
        return SpGrp
