Bonding nature of liquid Te over a wide temperature range

Liquid Te just above the melting point is a poor metal. Its structure is assumed to consist of short chains of covalently bound atoms, with strong chain-chain interaction causing metallic like properties. To study the temperature dependence of this structural arrangement, energy dispersive X-ray diffraction 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 that the position of the first peak in the structure factor is located around 2.1 Angstrom (-1) at 500 degreesC and shifts to 2.25 Angstrom (-1) for temperatures above 1300 degreesC. Additionally, an increase in the scattering intensity is observed around 1.4 Angstrom (-1) with rising temperature. The structural variations also influence the corresponding pair distribution functions, With increasing temperature. the first co-ordination shell shifts to larger distances but remains at a constant position above 1100 degreesC, suggesting a structural transition in this temperature range. This view is supported by temperature induced changes which are observed in the second coordination shell. (C) 2001 Elsevier Science B.V. All rights reserved.