The lattice-dynamical properties of the intermediate oxide of tin (IO)
have been investigated over the temperature range 80-295 K. The logar
ithm of the recoil-free fraction varied linearly with temperature. How
ever, a Debye model does not give a good account of this dependence. B
y comparison with the other oxides of the Sn-O system, the recoil-free
fraction for tin atoms with 2+ and 4+ oxidation states of the IO were
estimated. At room temperature, they are 0.46(3) and 0.32(3) for 4+ a
nd 2+ states respectively.