Density and surface tension of M₂O-TeO₂(M = Li, Na and K) melts

The density and the surface tension of the binary tellurite melts, (M ₂O-TeO₂ M = Li, Na and K) were measured. We investigated the thermal and compositional dependences of the properties. It was found that the density and the surface tension of the binary tellurite melts decreased with increasing temperature and M₂O content. The dependences of the density and the surface tension were attributed to the behavior of added cation and the structural change of melt. It was thought that the added cation intruded into the interspace of the complex tellurite anion, and molar volume decreased, when the radius of added cation was small. TeO₄ trigonal bipyramid changes to TeO₄" trigonal bipyramid and TeO₃ trigonal pyramid with increasing temperature and M₂O content. We explained that the dependences of the density and the surface tension on the behavior of added cation and the structural change of melt.