Neutron diffraction of liquid Sn-Se system

The time-of-flight neutron scattering measurements have been carried out for liquid Sn-Se system. A distinct change in structural properties has been observed between Sn₇₀Se₃₀ and Sn₆₀Se₄₀, composition of which corresponds to that of maximum of the miscibility gap. The atomic configuration of liquid SnSe have been compared to that of molten NaCl. It is found that the bonding nature between Sn and Se in liquid SnSe is ionic rather than covalent. A small but apparent pre-peak at Q = 1.2 Å^-1 in the structure factor for liquid SnSe₂ is found above the melting point. It suggests that the network structure remains after melting. The intensity of this pre-peak decreases with increasing temperature, indicating that the network structure is destroyed.