Containers sulfur hexafluoride

Sono Vue (BRl) is an ultrasound contrast medium that consists of microbubbles containing sulfur hexafluoride gas stabilized by phospholipids. The diameter of each microbubble is 2.5 pm and there are about 0.5 x 10 microbubbles/ml. It is isotonic with human plasma, has the same viscosity as blood, and has minimal antigenic potential, since it contains no protein material. 

Sulfur hexafluoride is packaged as a Hquefted gas in DOT 3AA 2015 steel cylinders containing 52 kg. Larger quantities are available in tube trailers containing ca 11,000 kg. 

Sulfur hexafluoride is a gas used as a long-term tamponade (plug) for a retinal hole to repair detached retinas in the eye. If 2.50 g of this compound is introduced into an evacuated 500.0-mL container at 83°C, what pressure in atmospheres is developed ... 

The flame ionization detector Is the most popular of the flame-based detectors. Apart from a reduction in sensitivity compared to expectations based on gas chromatographic response factors [138] and incompatibility with the high flow rates of conventional bore columns (4-5 mm I. 0.), the flame ionization detector is every bit as easy to use in SFC as it is in gas chromatography [148,149]. It shows virtually no response to carbon dioxide, nitrous oxide and sulfur hexafluoride mobile phases but is generally incompatible with other mobile phases and mixed mobile phases containing organic modifiers except for water and formic acid, other gas chromatographic detectors that have been used in SFC include the thermionic ionization detector (148,150], ... 

Routes of air-borne eontamination into BFS containers have been investigated during a study using sulfur hexafluoride (SFg) tracer gas [3]. During this experiment, the tracer gas was released into a elean room, housing an aseptic BFS machine, at a known concentration. Levels of the traeer gas were measured within subsequently filled BFS units. The study coneluded that the container was effeetively protected by the localized air shower. Although not necessarily representative of deposition of microbial contaminants, there was also eonclusive evidence of some room air within... 

At the time of the incident work site measurements qualitatively identified sulfur tetrafluoride in the air samples. It was suggested that intense heat caused sulfur hexafluoride to decompose to sulfur tetrafluoride, which escaped as a pipe was opened at the work site. Subsequent to this incident, it has been noted that because sulfur hexafluoride is an odorless gas, any odors present in areas containing heated sulfur hexafluoride must be considered to be coming from decomposition products, which are significant health hazards. 

A. Dinitrogen monoxide, sulfur hexafluoride, and dichlorine octoxide. Notice that none of these compounds contain any metals, which means that they re most certainly molecular compounds. The first compound contains two nitrogen atoms and one oxygen atom, so it s called dinitrogen monoxide. The second compound contains one sulfur and six fluorines. Because sulfur is the first named element, you don t need to include a mono- prefix. You simply name the compound sulfur hexafluoride (rather than monosulfur hexafluoride ). Using the same methods, the third compound is named dichlorine octoxide. 

For the analysis of sulfur hexafluoride an electron capture detector must be used. Analysis time for halothane, acetone, ether, cyclopropane, acetylenes, ethane, methane, and sulfur hexafluoride, under normal conditions, will average 8 min. Since the two detectors operate under different conditions samples containing both the hydrocarbons and sulfur hexafluoride are run through the gas chromatograph twice. By simultaneous use of separate ovens, the FID and ECD measurements can be made concurrently. Otherwise, the separate in jections must be made after switching the detectors. 

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

Sulfur, unlike oxygen, has the capacity to expand its valence shell beyond the normal octet of electrons to form hypervalent compounds such as sulfur tetrafluoride (SF4) with 10 electrons in the outermost shell and sulfur hexafluoride (SF6) containing 12 electrons in the valence shell.63,7 The chemistry of hypervalent sulfur started in 1873 with the discovery of the unstable compound sulfur tetrachloride (SCI4). The existence of hypervalent sulfur compounds is an important feature of the chemistry of sulfur and the precise nature of the bonding in these molecules has remained a puzzling problem. 

Describe the intermolecular forces that are present in each of the following compounds. Which kind of force would have the greatest influence on the properties of each compound (a) ethyl alcohol, C2HgO (contains one C—O single bond) (b) phosphine, PH3 (c) sulfur hexafluoride, SFg. 

To write the formula of a molecular compormd for which you are given the name, first write the symbols of each element in the order given in the name. Then add the appropriate subscript after each element that has two or more atoms present. Remember that the prefixes in the name teU how many atoms of each element are present. For example, the compound sulfur hexafluoride contains the elements sulfur and fluorine. Because the word sulfur has no prefix, it is understood that there is only one sulfur atom thus, the symbol S does not require a subscript. The prefix hexa tells you that six fluorine atoms are in the compound, so the subscript 6 must be added to the F. The formula for sulfur hexafluoride is SFg. Follow the rules for writing a formula for a molecular compound as you examine the formula shown in Figure 5.17. 

The product yields from the radiolysis of cyclohexane containing benzene, nitrous oxide, and sulfur hexafluoride, with electron pulses at a dose rate of 6 X 1027 e.v./gram sec. and a dose of 7 Mrads, are shown in Figures 4, 5, 6, and 7. Also included in these figures are data of other workers (12, 17) at ca. 1016 e.v./gram sec. with 60Co y-rays. Comparison between the results at the two dose rates shows that the effect of the additives is qualitatively the same. However, there are some differences in the amounts by which the yields change. 

Sulfur Hexafluoride, F6S mol wt 146.07. F 78.05%. S 2].95%. SFt. Prepd by direct fluorination of sulfur or sulfnr dioxide Moissan, Lebeau, Compt. Rend. 130, 865, 984 (1900) eidem, Ann. Chim. Phys. [7) 26, 147 (1902) Schumb, Inorg. Syn. 3, 119 (1950) Kwasnik in Handbook of Preparative lr.organic Chemistry, Vol, 1, G. Brauer. Ed. (Academic Press. New York, 2nd ed., 1963) pp 169-170. Reviews Cady, "Fluorine-Containing Compounds of Sulfur" in Advan. Inorg, Chem. Radiochem. 2, 105-157 (i960) Kemmitt, Sharp, Advan. Fluorine Chem. 4, 218-219 (1965). 

Sulfur hexafluoride is sold in cylinders containing 100 lb of the material at about 3 per lb (1959 price). It is used as the electrical insulator in coaxial cables, high voltage X-ray transformers, and high voltage generators (35, 211). Its availability is a stimulus to research dealing with the substance. Many studies use the substance because it is inert or because it is made up of nearly spherical molecules. There is also much theoretical interest in its structure and in the nature of the chemical bond involved. Many studies are related to its usefulness as an electrical insulator. 

Sulfur hexafluoride accelerates the pyrolysis of paraffin hydrocarbons (164), lowers the octane number of gasoline containing lead tetraethyl (189), removes silicon from a platinum catalyst when heated to 800 to 1000° (206) and catalyzes the reaction of ammonia with a ketone and aldehyde to give a substituted pyridine (196). It may be used at high pressure to fill a fuse. When the fuse blows an arc is prevented (210). 

Figure 7. Weight average molecular weight of polystyrene ( x 10 ) from free-radical polymerization of styrene in carbon dioxide + sulfur hexafluoride mixtures. Left. Influence of SF6 content at 56 MPa and 51 °C, 5 hr polymerization time. Right Influence of pressure in the solvent mixture containing 30 % by mass SFe at 51 °C. Pressure dependence of the density (in g/cm ) of the solvent mixture is shown on the right coordinate. [1 MPa = 10 bar],...

With water, nitrogen trifluoride forms a clathrate hydrate when ice at -25 to -40°C is exposed to pressurized NF3 (9 to 23 atm). Hydrate formation was found complete within 24 h by the fall of gas pressure. X-ray analysis indicated the clathrate hydrate to be of structure 1, space group Pm3n. The dielectric behavior and the F NMR spectrum of that hydrate as well of others containing tetrahydrofuran, p-dioxane, or sulfur hexafluoride as additional hosts, were analyzed to study the site distribution and motional dynamics of NF3 [1 ]. A crystalline clathrate... 

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