Trioxide

Abstract: Hydrogen trioxide (HO3) has long been postulated as a key intermediate in important atmospheric processes but has proved difficult to detect. The molecule was unequivocally detected in experiments based on neutralization-reionization and neutralization-reionization/collisionally activated dissociation mass spectrometry, using protonated ozone (HO3+) as the charged precursor. Hydrogen trioxide is a relatively stable species and has a H-O-O-O connectivity and a lifetime exceeding 10–6 seconds at ambient temperature.

Abstract: The phase equilibrium diagram for the binary system niobium pentoxide-tungsten trioxide has been constructed from results of x-ray diffraction studies on both single crystals and powders and from fusion characteristics. Twelve stable compounds have been found in the system. The exact composition of eight of these compounds has been established by single crystal analyses at the Nb2O5:WO3 ratios of 6:1, 13:4, 7:3, 8:5, 9:8, 1:1, 4:9, and 2:7. The approximate compositions of the remaining four other phases are 30:1, 6:11, 1:11, and 1:15. The 6:1, "6:11", 4:9, and 2:7 phases melt eongruently at 1476, 1378, 1380, and 1357 °C, respectively. The "30:1", 7:3, 8:5, 9:8, "1:11", and "1:15" phases melt incongruently at 1470, 1440, 1385, 1375, 1356, and 1358 °C, respectively; and the 13:4 and 1:1 phases decompose before melting at 1435 and 1115 °C, respectively. The 8:5, 9:8, "6:11", 2:7, "1:11", and "1:15" compounds are shown on the phase diagram as having minimum temperatures of stability. One metastable phase having a narrow range of composition near the 3:8 ratio was also encountered. Although Nb2O5 apparently exhibits no solid solution, WO3 was found to accept a maximum of three mole percent niobia in solid solution enabling all the reported polymorphs of WO3 to be obtained at room temperature.

Abstract: The rates and extents of hydrogen sorption by platinised tungsten trioxide and molybdenum trioxide have been measured between 273 and 363 K and between 3 and 101 kN m–2. Maximum diffusion coefficients for hydrogen spilling-over from platinum to the trioxide supports have been estimated. X-Ray diffraction, differential thermal analysis and thermogravimetric analysis, e.s.r. and i.r. spectroscopy indicate that the products of this spillover are hydrogen bronzes of tungsten and molybdenum. These may be represented as HxWO3, where x has a maximum value of 0.46, and HxMoO3, where x has a maximum value of 1.63. The latter violates the ranges of composition previously accepted for bronzes. The chemical and thermal stability of these bronzes is discussed in terms of their structures.