Publication Date:
2020-07-13
Description:
${ext{Pb}}_{5}{ext{O}}_{2}left[{ext{WO}}_{6}
ight]$ was discovered as a frequently observed side phase during our investigation on lead tungstates. Its crystal structure was solved by single-crystal X-ray diffraction ($P{2}_{1}/n$, $a=7.4379left(2
ight)$ Å, $b=12.1115left(4
ight)$ Å, $c=10.6171left(3
ight)$ Å, $ eta =90.6847left(8
ight)$°, $Z=4$, ${R}_{ext{int}}=0.038$, ${R}_{1}=0.020$, $omega {R}_{2}=0.029$, 4188 data, 128 param.) and is isotypic with ${ext{Pb}}_{5}{ext{O}}_{2}left[{ext{Te}}_{6}
ight]$. ${ext{Pb}}_{5}{ext{O}}_{2}left[{ext{WO}}_{6}
ight]$ comprises a layered structure built up by non-condensed [WO6]${}^{6-}$ octahedra and ${left[{ext{O}}_{4}{ext{Pb}}_{10}
ight]}^{12+}$ oligomers. The compound was characterised by spectroscopic measurements (Infrared (IR), Raman and Ultraviolet–visible (UV/Vis) spectra) as well as quantum chemical and electrostatic calculations (density functional theory (DFT), MAPLE) yielding a band gap of 2.9 eV fitting well with the optical one of 2.8 eV. An estimation of the refractive index based on the Gladstone-Dale relationship yielded $napprox 2.31$. Furthermore first results of the thermal analysis are presented.
Print ISSN:
2194-4946
Electronic ISSN:
2196-7105
Topics:
Geosciences
,
Physics
Permalink