  In this paper we propose that phonons, free diffusive electrons, and
diffusion in two-and three--dimensional disordered lattice problems belong to a
different class of localization than bonded electrons. This is manifested by
three effects that can be observed numerically. First, there are extended
states even at two dimensions, whereas there are no extended states in the
usual electronic models. Second, the correlation length does not diverge at the
mobility edges in three dimensions, and finally, the participation ratio of the
extended states, decays to zero at this edge. This indicates zero electronic
conductivity, in the extended region near the mobility edge. We show that low
energy modes for these models can either have diverging localization lengths or
are extended.
