Phosphorus hexafluoride

In addition to iodonium, sulfonium and selenonium compounds, onium salts of bromine, chlorine, arsenic, and phosphoras are also stable and can act as sources of cation radicals as well as Bronsted acids, when irradiated with light. Performance of diaryl chloronium and diaryl bromonium salts was studied by Nickers and Abu. Also, aryl ammonium and aryl phosphonium, and an alkyl aryl sulfonium salt were investigated. It appears that the general behavior of these materials is similar to diphenyl iodonium and triphenyl sulfonium salts. These are formations of singlet and triplet states followed by cleavages of the carbon-onium atom bonds and in-cage and out of cage-escape reactivity. The anions of choice appear to be boron tetrafluoride, phosphorus hexafluoride, arsenic hexafluoride, and antimony hexafluoride. 

Adhesion studies Rattana and co-workers [231] and Watts and co-workers [232] have studied the adhesion of aluminium and epoxy resins nsing amine and organosilane primers. Leadly and co-workers [261] give details of coating delamination in a hot, humid environment for a cationic radiation-cured coating of cycloaliphatic epoxy resin. XPS and ToF mass spectroscopy of the delaminated snrface showed that the phosphorus hexafluoride anion of the photoinitiator segregates to the interface. The durability of the coating was improved by reformulation with a rednced concentration of photoinitiator. 

The largest class of molecules to violate the octet rule consists of species in which the central atom is surrounded by more than four pairs of valence electrons. Typical molecules of this type are phosphorus pentachloride, PC15, and sulfur hexafluoride, SF6. The Lewis structures of these molecules are... 

C03-0075. Calculate the number of molecules present in 5.86 mg of each of the following compounds (a) methane (CH4) (b) phosphorus trichloride (c) dimethyl ether (C2 Hg O) and (d) uranium hexafluoride. 

In plastic crystals all or a part of the molecules rotate about their centers of gravity. Typically, plastic crystals are formed by nearly spherical molecules, for example hexafluorides like SF6 or MoF6 or white phosphorus in a temperature range immediately below the melting point. Such crystals often are soft and can be easily deformed. 

Ans. (a) Carbon monoxide, (b) sulfur dioxide, (c) sulfur trioxidc, (d) carbon tetrachloride, (e) phosphorus pentachloride, and (/) sulfur hexafluoride. 

Nonmetals, such as sulfur, phosphorus and carbon (amorphous) inflame in fluorine forming their corresponding fluoro compounds, such as sulfur hexafluoride (SFe), phosphorus pentafluoride (PF5), and carbon tetrafluoride (CF4). 

Sulfur hexafluoride may be passed through water, dried over phosphorus pentoxide, and further purified by repeated sublimation of the solid at low temperatures and pressures. Selenium and tellurium hexafluoride are best purified by repeated sublimation at the temperature of solid carbon dioxide, care being taken to cause the middle fraction to melt after each sublimation. The less volatile impurities consist principally of lower fluorides (tetrafluorides). 

Trimethylsiloxy tellurium pentafluoride reacted with sulfur tetrafluoride or phosphorus pentafluoride forming tellurium hexafluoride and fluorotrimethylsilane1. 

Examples of molecules in which the central atom contains an expanded octet are the phosphorus pentahalides and sulfur hexafluoride. 

The reaction between molybdenum hexacarbonyl and elemental fluorine at —65° results in the formation of Mo2F9, which upon thermal degradation produces molybdenum pentafluoride as one of the products.1 Other syntheses of molybdenum pentafluoride include the reduction of molybdenum hexafluoride with phosphorus trifluoride,2 tungsten hexacarbonyl, or molybdenum metal at high temperatures3 and the oxidation of powdered molybdenum metal with elemental fluorine at 900°.3 The present method consists in the reaction of molybdenum hexafluoride with powdered molybdenum metal at 60° and results in the formation of pure molybdenum pentafluoride in yields of 80% and greater. 

FIG. 15-5. Molecules of silicon tetrafluoride, phosphorus penta-fluoride, and sulfur hexafluoride, three very volatile substances. 

The pattern of graphite intercalation by hexafluorides of the third transition series [1] had indicated that the intercalation of such molecules, to form Cx MFs salts, requires a minimum electron affinity of approximately 120 kcal mor. Such a threshold electron affinity also accounts [2, 3] for the spontaneous intercalation of graphite by arsenic pentafluoride and for the failure of the physically similar pentafluoride of phosphorus to do likewise. For the half reaction... 

Trimethylsilylamino tellurium pentafluoride lost the trimethylsilyl group in reactions with hydrogen fluorideS cesium fluoride, chlorine fluoride, sulfur fluorides, selenium tetrafluo-ride, phosphorus pentafluoride, tungsten hexachloride, molybdenum hexafluoride, and tungsten hexafluoride. ... 

Example 5 Phosphorus Pentachioride (PCI3) and Sulfur Hexafluoride(SF )... 

SULFUR HEXAFLUORIDE (2551-62-4) Hydrolyzes in hot water, forming hydrofluoric acid. Violent reaction with chromyl chloride, diethylzinc, dimethyl sulfoxide, disilane, lead dioxide, nitric acid, red phosphorus, potassium, sodium peroxide. Incompatible with hexafluoroisopropylideneaminolithium. 

Fluorophosphites are also among the products from reactions between (a) trimethylphosphite and tungsten hexafluoride 251), (6) alcohols and dichlorofluorophosphine 55, 67, 205), (c) phosphorus pentafluoride or trifluorophosphine and trimethylphosphite 35), and d) epoxides and trifluorophosphine in the presence of a tertiary amine 150), but these are of less importance from a preparative viewpoint. The attempted... 

Phosphorus pentafluoride Polarine oil Selenium mustard Silicon tetrafluoride Strontium chlorate Strontium permanganate Sulfur chloropentafluoride Sulfur dichloride Sulfur hexafluoride Sulfur monochloride Titanium tetrachloride Thiocarhonyl dichloride Thionyl fluoride Thioptiosgene Triethyl aluminum Trifluoromethyl iodide Triisohutylaluminum Trimethylaluminum Vanadium tetrachloride Vincennite Vinyl bromide Vinylmagnesium bromide Xenon difluoride Zinc arsenide... 

Perchloric acid Phosphomolybdic acid Phosphorus oxychloride Phosphorus pentachloride Phosphorus trichloride y-Picoline Polyphosphoric acid Potassium silicate Rhodium Selenium Selenium dioxide Silica gel Silver oxide (ous) Sodium borohydride Sodium silicate Strontium carbonate Sulfur dioxide Tantalum Tellurium Tetraisopropyl di (dioctylphosphito) titanate Titanocene dichloride Trichloromethylphosphonic acid Tristriphenylphosphine rhodium carbonyl hydride Tungsten carbide Vermiculite Ytterbium oxide Zinc chloride Zinc dust Zinc 2-ethylhexanoate Zirconium potassium hexafluoride... 

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