DETERMINATION OF DEFECT MOLECULAR UNITS IN K2SnCl6 AND AMMONIUM HALIDES VIA DIPOLAR RELAXATION AT PHASE TRANSITIONS J. WINTER and K. RÖSSLER J. Phys. Colloques, 37 C7 (1976) C7-265-C7-270 DOI: 10.1051/jphyscol:1976763