Raman spectroscopy evidence of 1:1:1 complex formation during dissolution of WO3 in a melt of K2S2O7:K2SO4

Abstract

Highly inert yellow solid WO 3 was found to be soluble in considerable amounts in molten K 2 S 2 O 7 at elevated temperatures ($650 8C), if only similar molar amounts of sulfates were also present. The dissolution reaction of WO 3 into a melt consisting of a 1:1 molar mixture of K 2 S 2 O 7 and K 2 SO 4 was studied in detail, and Raman spectroscopy was used to characterize the products. In combination with single crystal X-ray crystal structure determination, it was shown that a new dimeric compound, K 8 [{W VI O 2 (SO 4 ) 2 } 2 (m-SO 4 ) 2 ], was formed and its assigned Raman spectrum at room temperature is given. The WO 2 2+ cores of the dimeric complex have their symmetrical and antisymmetrical stretching modes n 1 (WO 2 2+ ) and n 3 (WO 2 2+ ) at around 1054 (strong) and 1042 (weak), and the bending mode n 2 (WO 2 2+ ) at around 292 (medium intensity), respectively (positions given in cm À1 ). #

Water vapor pressure over molten KH2PO4 and demonstration of water electrolysis at ∼300 °C

“…In order to obtain reliability the measurements were repeated, averaged, scaled and shifted with the Labspec software but not further corrected. Other experimental details have been described elsewhere [13,14].…”

Vapor pressure and specific electrical conductivity in the solid and molten H2O-CsH2PO4-CsPO3 system—a novel electrolyte for water electrolysis at ~ 225–400 °C

“…Measurements. Raman spectra were measured by use of a DILOR-XY 800 mm focal-length Czerny-Turner type spectrometer with 90° macro entrance and a 10 x 10 cm 2 1800 lines/mm plane holographic grating [84]. Excitation was done with laser light from a doubled Nd-YPO 4 Laser (wavelength 532 nm CW vertically polarized at a power setting of up to ~1.5 W).…”

Raman detection of hydrohalite formation: Avoiding accidents on icy roads by deicing where salt will not work

“…The frozen solids were used directly for obtaining Raman spectra. Stationary Raman setups were used consisting of DILOR-XY or Renishaw-inVia Spectrometers with standard or UVenhanced Suprasil™ quartz optics, microscopes, highly sensitive cooled CCD detectors and other necessary accessories described in [41]- [43]. Excitation was done with light from doubled Nd 3+ solid state and Ar + gas lasers operating at 532, 514.5 and 488.0 nm.…”