We have studied the effect on NH3 rotation of changing the M(I) metal
in the Hofmann clathrates M(I)(NH3)(2) Ni(CN)(4)2C(6)D(6) where M(I) =
Cu, Fe, Mn, Ni, Zn. Only slight changes in the energy of the NH3 roto
r peak are observed. In contrast, the empty host compound Ni(NH3)(2) N
i(CN)(4) shows a marked increase in the rotational barrier.