High-pressure synthesis and crystal structure analysis of PbTeO, a UV transparent material.

Using the additional parameter pressure (Walker-type multianvil device), the lead(II) oxidotellurate(VI) PbTeO was synthesized at conditions of 8 GPa and 750 °C, and for the first time its crystal structure was determined using single-crystal X-ray diffraction data. PbTeO crystallizes with four formula units in the monoclinic space group 2/ with unit cell parameters = 5.4142(4), = 4.9471(4), = 12.0437(11) Å, = 99.603(3)°, and = 318.07(5) Å. UV-Vis measurements revealed UV transparency down to 200 nm. From the diffuse reflectance data experimental band gaps ( = 2.9 eV/ = 2.8 eV) were determined and compared with calculated values. Temperature-dependent X-ray powder diffraction and complementary thermal analysis measurements revealed a stability range of PbTeO up to 625 °C. Additionally, theoretical calculations at DFT level of theory were carried out to obtain the electronic band structure, X-ray powder diffraction patterns, IR/Raman vibrational spectra and Mulliken partial charges. The electron localization function (ELF) was visualized to emphasize the presence of the electron lone pair in the coordination sphere of the Pb atom.