Bonding nature of liquid Te over a wide temperature range

Liquid Te just above the melting point is a poor metal. Its structure is as sumed to consist of short chains of covalently bound atoms, with strong cha in-chain interaction causing metallic like properties. To study the tempera ture dependence of this structural arrangement, energy dispersive X-ray dif fraction measurements were carried out on liquid Te in a temperature range between 500 and 1700 degreesC and applied pressure of 50 bar. It is found t hat the position of the first peak in the structure factor is located aroun d 2.1 Angstrom (-1) at 500 degreesC and shifts to 2.25 Angstrom (-1) for te mperatures above 1300 degreesC. Additionally, an increase in the scattering intensity is observed around 1.4 Angstrom (-1) with rising temperature. Th e structural variations also influence the corresponding pair distribution functions, With increasing temperature. the first co-ordination shell shift s to larger distances but remains at a constant position above 1100 degrees C, suggesting a structural transition in this temperature range. This view is supported by temperature induced changes which are observed in the secon d coordination shell. (C) 2001 Elsevier Science B.V. All rights reserved.