Platinum products

In addition to the presence of these elements in ores, they are also available from recycled feeds, such as catalyst wastes, and as an intermediate bulk palladium platinum product from some refineries. The processes that have been devised to separate these elements rely on two general routes selective extraction with different reagents or coextraction of the elements followed by selective stripping. To understand these alternatives, it is necessary to consider the basic solution chemistry of these elements. The two common oxidation states and stereochemistries are square planar palladium(II) and octahedral platinum(IV). Of these, palladium(II) has the faster substitution kinetics, with platinum(IV) virtually inert. However even for palladium, substitution is much slower than for the base metals so long as contact times are required to achieve extraction equilibrium. 

Insoluble impurities fall to the floor of the cell as anode slime. Despite the derogatory name, this material contains precious metals such as gold, silver, and platinum. Anode slime from the electrorefining of nickel11 at Sudbury, Ontario, is a significant source of platinum and palladium as byproducts ( 0.34 g Pt and 0.36 g Pd per metric ton of ore), whereas deposits in the Bushveld complex (Transvaal, South Africa) are so rich in platinum-group metals (Ru, Os, Rh, Ir, Pd, Pt) that the associated Co, Ni, and Cu recovered are considered to be by-products of the lucrative platinum production (4.78 g Pt and 2.03 g Pd per metric ton of ore).7... 

The reaction of xenon with platinum hexafluoride yields at least two distinct quinquevalent platinum products, XePtF, and Xe(PtFj)j. A third compound XePtjFij which is diamagnetic, is produced by heating the former. During continuing investigations of the reaction between xenon, fluorine, and platinum pentafluoride, at least two different compounds have been detected. The better characterized compound is produced when 1 1 molar ratios of xenon and platinum pentafluoride are employed in admixture with 80 p.s.i. 

Fraval HNA, Rawlings CJ, Roberts JJ. Increased sensitivity of UV repair deficient human cells to DNA bound platinum products which unlike thymine dimers are not recognized by an endonuclease extracted from Micrococcus leuteus. Mutat Res 1978 51 121-32. 

Oxidation of organic substrates at a graphite anode often results in products other than oxidation at a platinum electrode the tendency to further oxidation of a primarily produced radical to a carbocation seems higher at carbon than at platinum. Products obtained at graphite, glassy carbon, or other forms of carbon may differ considerably [148-151]. Glassy carbon is difficult to work mechanically. 

South America. He noticed that it formed compounds with bright colors. A rare element, it is part of the platinum group and is used primarily in platinum products. It is resistance to all acids, so it is also used for laboratory equipment. 

The name comes from Ruthenia, Latin for Russia. In 1840, Karl Karlovich Klaus (1796-1864) started an investigation to settle a dispute between Gottfried Wilhelm Osann (1797-1866) and Jons Jakob Berzelius (1779-1848) over the existence of new elements in residue from platinum ore found in the Ural Mountains. In 1844, Klaus identified and named the new element. Small quantities of ruthenium are found in platinum and nickel ores. It is used primarily as a catalyst and a hardening alloy for platinum products. 

The rednction-adsorption capacity for Pt (IV) on activated carbon fibers obtained from viscose rayon, sisal, and pitch was stndied by Fu et al. by chemical analysis of the reaction solutions and XPS studies of the deposited platinum. The reduction-adsorption capacity increased with the time of activation of the carbon fiber and was the highest in the case of viscose-based carbon fibers. Viscose-based carbon fibers were capable of reducing appreciable amonnts of Pt (IV), even withont activation. The state of the platinum product depended on the reaction conditions. Under acidic reaction conditions, the deposited platinnm was mainly in the elemental state. However, under the alkaline conditions, the liquid-phase hydrolysis of Pt (IV) becomes significant, and most of the platinum deposited on the activated carbon fiber surface was present as PtO, which was not further reduced to the metallic... 

Rhodium is present at about 0.001 ppm in the earth s crust. Its production is estimated to be as low as 2% and as high as 10% of the platinum production. Russia is thought to have about half of the world s supply. 

Other primary silanes react as well but the platinum products... 

While there is some formal similarity between the first part of reactions (25) and (16), the platinum product formed in equation (26) is not that expected in a conventional oxidative addition process. 

The synthesis and X-ray crystal structures of some (p,i 2 T 5)-di5ofapentafulvalene derivatives of the [Mfri -COD)] (M = Ni, Pt) fragment, such as (20), have been reported263. The reaction of [M(ti -COD)21 (M = Ni, Pt) with the stable nucleophilic carbene 1,3-dimesitylimidazol-2-ylidene was reported M to form two-coordinate homoleptic bis(carbene) adducts. The X-ray structures of both nickel and platinum products were determined. 

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