Hexafluoride ion

Fig. 11. Variation in i F shielding down the group of the central atom in hexafluoride ions and molecules and in halogen pentafluorides. Explanation of symbols ...

Fluoride ion is more effective than the other halide ions in forming complexes. Important examples are the tetrafluoroborate ion, Bp4, the hexafliiorosilicate ion, SiFg, the hexafluoroalumimite ion, AlFg, and the ferric hexafluoride ion, FeFe. ... 

The silicon hexafluoride ion, SiFg, is octahedral. What orbitals of the silicon atom are occupied by unshared electron pairs By bonding electron pairs What is the electric charge on the silicon atom and each fluorine atom, as calculated from electronegativity values ... 

Fluoride ions reacting with a silicon tetrafluoride molecule to form the silicon hexafluoride ion ... 

Fluorides can be detected with high sensitivity through their reaction with zirconium alizarinate . This test (page 221) is based on the facts that, in mineral acid solution, zirconium salts yield a red-violet color with alizarin and that this color changes to yellow (the color of acid alizarin solution) on the addition of excess fluoride because of the production of complex zirconium hexafluoride ions. The reactions can be represented by ... 

Electrica.1 Properties. The electrical properties of SF stem primarily from its effectiveness as an electron scavenger. To accomplish electrical breakdown in a dielectric gas, primary electrons must gain sufficient energy to generate appreciable numbers of secondary electrons on molecular impact. Sulfur hexafluoride interferes with this process by capturing the primary electrons, resulting in the formation of SF or SF ions and F atoms (29) ... 

In TBP extraction, the yeUowcake is dissolved ia nitric acid and extracted with tributyl phosphate ia a kerosene or hexane diluent. The uranyl ion forms the mixed complex U02(N02)2(TBP)2 which is extracted iato the diluent. The purified uranium is then back-extracted iato nitric acid or water, and concentrated. The uranyl nitrate solution is evaporated to uranyl nitrate hexahydrate [13520-83-7], U02(N02)2 6H20. The uranyl nitrate hexahydrate is dehydrated and denitrated duting a pyrolysis step to form uranium trioxide [1344-58-7], UO, as shown ia equation 10. The pyrolysis is most often carried out ia either a batch reactor (Fig. 2) or a fluidized-bed denitrator (Fig. 3). The UO is reduced with hydrogen to uranium dioxide [1344-57-6], UO2 (eq. 11), and converted to uranium tetrafluoride [10049-14-6], UF, with HF at elevated temperatures (eq. 12). The UF can be either reduced to uranium metal or fluotinated to uranium hexafluoride [7783-81-5], UF, for isotope enrichment. The chemistry and operating conditions of the TBP refining process, and conversion to UO, UO2, and ultimately UF have been discussed ia detail (40). 

No evidence for PUO3 has been reported in mass spectrometric studies (31). However, the existence of the Pu + ion has been established by the observation of the hexafluoride (32). We have not included any Pu + in our calculations. 

From a knowledge of the free-ion B values the ft parameters are readily derived. For most di configurations these represent /J35 quantities, but as explained before (7) for d3 and d8 systems respectively 55 and fizz parameters may also in principle be deduced. In the present work the (S values listed are always /S35 parameters unless otherwise stated, but for the 5d systems OsFe- and IrFij and the 5d2 system OsF6 the ft values are essentially 55 quantities since they are obtained predominantly from bands arising from the t t manifold. The and Dq parameters derived for the 4 d and 5 d hexafluorides are now given in Table 22. 

Plutonium compounds, 19 687-691 protection against, 19 702 Plutonium dioxide, 19 688—689 Plutonium fuel fabrication facilities, 17 547 Plutonium-gallium alloys, 19 683-684 Plutonium halides, 19 689-690 Plutonium hexafluoride, 19 689 Plutonium hydrides, 19 690 Plutonium ions... 

Sulfur hexafluoride production, 11 846 Sulfur hexafluoride reactive ion etching, in lotus effect surfaces, 22 120 Sulfuric acid, 24 260, 12 190, 23 563, 669, 754-801... 

Xenon fluorides, 77 323-325 binary, 77 335-336 Xenon-gold cations, 77 332 Xenon halides, 77 323-325 Xenon hexafluoride, 7 7 325, 329 uses for, 7 7 336 Xenon ion lasers, 74 685 Xenon isotopes, in fission reactors, 77 375 Xenon oxide difiuoride, 77 326 Xenon oxide fluorides, 7 7 326 Xenon oxides, 77 325-326 Xenon oxide tetrafluoride, 77 326 Xenon testing, in plastics weathering, 79 584-585... 

De Wall, R. Neuert, H. The Formation of Negative Ions From Electron Impact Widi Tungsten Hexafluoride. Z Naturforsch., A 1977,32A, 968-971. 

Elemental composition Se 40.92%, F59.08%. The gas may be dissolved in nitric acid and dilute hydrofluoric acid and the solution appropriately diluted and analyzed for selenium (see Selenium). The hexafluoride may be decomposed with ammonia at 200°C and product selenium analyzed by AA, and gaseous products nitrogen and hydrogen fluoride diluted with helium and analyzed by GC-TCD or GC/MS. Alternatively, selenium hexafluoride diluted with helium is introduced onto the GC injector port and analyzed by GC/MS. Molecular ions have masses 194, 192, 196, and 190. 

There have been some unsuccessful attempts to prepare a volatile hexafluoride from fluorine and polonium-210 26, 104), but recently such a fluoride has been prepared in this way from polonium-208 plated on platinum 132). The product appears to be stable while in the vapor phase, but on cooling a nonvolatile compound is formed, probably polonium tetrafluoride resulting from radiation decomposition of the hexafluoride. Analytical data are not recorded for any polonium fluoride, largely owing to the difficulty of determining fluoride ion accurately at the microgram level. 

Extensive work has been done on the hyperfine interaction of the hexafluoride complexes of several transition ions (29, 39-45). To illustrate the approach used in interpreting the superhyperfine interaction, we shall consider the case of the ds configuration of Mn2+ and Fe3+. For this case we have an 6S-state ion with each d orbital singly occupied. The equations for the five antibonding MO s are... 

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