Structure of disordered forms of selenium close to the melting point

Large structural models of liquid and amorphous selenium have been constructed that are consistent with the most up to date diffraction results obtained for these materials. It is found that close to the melting point liquid Se may already form only very short (up to Nₘₐₓ=8) chains, whereas for the amorphous form diffraction data are consistent with the presence of essentially infinite chains. Some aspects of the interpretation of liquid and amorphous solid diffraction data in general are also discussed.