Tetrafluoride physical properties

Physical Properties. Sulfur tetrafluoride has the stmcture of a distorted trigonal bipyramid, the sulfur having hybrid sp d orbitals and an unshared electron pair (93). The FSF bond angles have been found to be 101° and 187°, and the bond distances 0.1646 and 0.1545 nm (94). 

Uses. The chemical inertness, thermal stability, low toxicity, and nonflammability of PFCs coupled with their unusual physical properties suggest many useflil applications. However, the high cost of raw materials and manufacture has limited commercial production to a few, small-volume products. Carbon tetrafluoride and hexafluoroethane are used for plasma, ion-beam, or sputter etching of semiconductor devices (17) (see loN implantation). Hexafluoroethane and octafluoropropane have some applications as dielectric gases, and perfluorocyclobutane is used in minor amounts as a dielectric fluid. Perfluoro-1,3-dimethyl cyclohexane is used as an inert, immersion coolant for electronic equipment, and perfluoro-2-methyldecatin is used for... 

The physical properties of zirconium tetrafluoride ate Hsted in Table 7. 

Physical Properties and Molecular Parameters of Group VI Tetrafluorides"... 

Basic physical properties of sulfur tetrafluoride are given in Table l.2-3... 

Physical properties of the Xe-PtFt adduct.—The adduct is yellow when deposited in thin films but in bulk is deep red. The solid becomes glassy in appearance when heated to 115°, but does not melt below 165°, when it decomposes to produce xenon tetrafluoride. X-ray powder photographs of the adduct of composition XePtFe show no diffraction pattern. Complex patterns are observed with samples of material richer in platinum. The plasticity of the material made the preparation of good powder samples difficult. Even well-cooled samples did not grind well. 

The oxide pentafluoride has been prepared and a preliminary report has been given. Its crystal and molecular structure is presented in the following paper and its preparation and some physical properties are given below. No evidence for the dioxide tetrafluoride has been obtained. 

The 1 1 chlorine trifluoride-platinum pentafluoride adduct, m. p. I7l , and the 1 1 iodine pentafluoride adduct, m. p. 140° resemble, in their physical properties, the selenium tetrafluoride adducts of osmium pentafluoride (SeF4,OsFg, m. p. 158°) and iridium pentafluoride (SeF. IrFg, m. p. 133°). They are probably bifluorine-bridged monomers ... 

Although a number of complex fluorides of quinquevalent iridium, (e.g. KIrF,) are known, previous attempts to establish the simple fluoride have failed. The absence of a pentafluoride of iridium has become increasingly anomalous as the pentafluorides of the neighbouring elements, rhenium, osmium, and platinum have been prepared. Previous work - indicated that reactions which might have yielded the pentafluoride gave the tetrafluoride instead. The physical properties of this tetrafluoride. (m.p. 106—107 b.p. > 300 ), however, resembled those of a pentafluoride or oxide tetrafluoride. This indicated that iridium tetrafluoride differed structurally from its neighbouring tetrafluorides. 

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