Platinum 4 2+, structure

The platinum structure is FCC (see Figure 2.4) and the electronic arrangement of Pt is [Xe]5d96s1]. The band structure of platinum is also the cause of its catalytic properties. Platinum does not form very strong, nor weak bonds, and is, consequently, one of the most active among the transition metals in several reactions. In fact, platinum is a multipurpose, heterogeneous metallic catalyst,... 

Figure 6.41. Evolution of surface potential as a function of oxygen pressure (1 mbar = 100 Pa) beta-alumina - platinum structure...

It is desirable to show how new platinum structures may differ in signalling pathways from those of cisplatin and oxaliplatin. An important example is the role of pS3, the tumor suppresor g te, in modulation of cytotoxicity of platinum drugs. BBR 3464 di lays high activity in human tumor cell lines characterized by both wild type and mutant pS3 gene (21). In contrast, on average, cells with mutant pS3 are more resistant to the effea of cisplatin (25). It has been hypothesized that sensitivity or resistance of tumor cells to cisplatin might be also associated widi the processes involving pS3 (26,27). Transfer of functional pS3 into p53-null SAOS osteosarcoma cells actually reduced cellular sensitivity... 

Ethene can add on to certain metal salts it is believed that the extra electrons of the double bond can be donated to some extent an example is the compound PtCl2-C2H4 formed with platinum(II) chloride which has the structure... 

Hydrogenation of 3 carene is in pnnciple capable of yielding two stereoisomenc products Wnte their structures Only one of them was actually obtained on catalytic hydrogenation over platinum Which one do you think is formed" Explain your reasoning with the aid of a drawing or a molecular model... 

An unknown acetylenic ammo acid obtained from the seed of a tropical fruit has the molec ular formula C7H11NO2 On catalytic hydrogenation over platinum this ammo acid yielded homoleucme (an ammo acid of known structure shown here) as the only product What is the structure of the unknown ammo acid" ... 

A large number of organometallic compounds are based on transition metals Examples include organic derivatives of iron nickel chromium platinum and rhodium Many important industrial processes are catalyzed by transition metals or their complexes Before we look at these processes a few words about the structures of transition metal complexes are m order... 

Since detailed chemical structure information is not usually required from isotope ratio measurements, it is possible to vaporize samples by simply pyrolyzing them. For this purpose, the sample can be placed on a tungsten, rhenium, or platinum wire and heated strongly in vacuum by passing an electric current through the wire. This is thermal or surface ionization (TI). Alternatively, a small electric furnace can be used when removal of solvent from a dilute solution is desirable before vaporization of residual solute. Again, a wide variety of mass analyzers can be used to measure m/z values of atomic ions and their relative abundances. 

Usually they are employed as porous pellets in a packed bed. Some exceptions are platinum for the oxidation of ammonia, which is in the form of several layers of fine-mesh wire gauze, and catalysts deposited on membranes. Pore surfaces can be several hundred mVg and pore diameters of the order of 100 A. The entire structure may be or catalytic material (silica or alumina, for instance, sometimes exert catalytic properties) or an active ingredient may be deposited on a porous refractory carrier as a thin film. In such cases the mass of expensive catalytic material, such as Pt or Pd, may be only a fraction of 1 percent. 

Phosphoric Acid Fuel Cell This type of fuel cell was developed in response to the industiy s desire to expand the natural-gas market. The electrolyte is 93 to 98 percent phosphoric acid contained in a matrix of silicon carbide. The electrodes consist of finely divided platinum or platinum alloys supported on carbon black and bonded with PTFE latex. The latter provides enough hydrophobicity to the electrodes to prevent flooding of the structure by the electrolyte. The carbon support of the air elec trode is specially formulated for oxidation resistance at 473 K (392°F) in air and positive potentials. 

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