Radical anions and radical trianions derived from 5-methylene-5-dibenzo [,] cycloheptene, 10-deuterio-5-methylene-5-dibenzo [,] cycloheptene and 5-dideuteriomethylene-5--dibenzo [,] cycloheptene by reduction with lithium, sodium, potassium and caesium in ethereal solvents have been studied by EPR, ENDOR and TRIPLE r