Platinum electron configuration

Despite the fact that PtL3X2 and PtXs- species have an 18-electron configuration, 5-coordinate palladium(II) and platinum(II) compounds are rare. One of the first examples to be established was Pt(SnCl3)5-... 

Like palladium(II) and platinum(II), gold(III) has the d8 electronic configuration and is, therefore, expected to form square planar complexes. The d-orbital sequence for complexes like AuC14 is dx2 yi dxy > dvz, dxz > dzi in practice in a complex, most of these will have some ligand character. 

Fig. 10. Half wave potentials (at a rotating platinum electrode) vs. d-electron configuration for Et2dtc complexes. The E1/2 values depend upon solvent and reference electrode used (see text), but this is a minor effect as compared with the influence of the d-electron configuration.

The electronic configuration of tin after loosing two p electrons to form Sn2 + is 5s2. The <7-donor tendency of tin is relatively small but can be enhanced in the presence of a powerful acceptor, especially if the empty 5d orbitals of tin can act as n-acceptors [104]. This could be the situation for adsorbed Sn(II). Platinum may act as an acceptor of the tin a electrons while 5d orbitals of the latter accept 7t-electrons from H20 to build an adsorbed Sn(OH)+ complex ... 

The kinetically-stabilized complexes of the cage ligands normally yield redox reagents free of the exchange problems often associated with simple complexes. Indeed, the redox chemistry of the complexes shows a number of unusual features for example, saturated cages of the type mentioned in Chapter 3 are able to stabilize rare (monomeric) octahedral Rh(n) species (d7 electronic configuration) (Harrowfield etal., 1983). In a further study, radiolytical or electrochemical reduction of the Pt(iv) complexes of particular cages has been demonstrated to yield transient complexes of platinum in the unusual 3+ oxidation state (Boucher et al., 1983). 

Similar open structures containing platinum atoms with a 16 electron configuration have been found in Pt4(CO)5(PPhMe2)4 239 and in Pt2Co2(CO)8(PPh3)2 95 as shown in Fig. 19. 

Duncanson (i) of the molecular orbital bonding concepts of Dewar (2), which he developed to explain the structure of Ag+-olefin complexes, led to the suggestion that ethylene is symmetrically coordinated to the metal. Platinum, atomic number 78, has the electronic configuration of the xenon core (Is 2s 2p 35 3p 3d Z = 54), then... 

The most common oxidation state of palladium is H-2 which corresponds toa electronic configuration. Compounds have square planar geometry. Other important oxidation states and electronic configurations include 0 ( °), which can have coordination numbers ranging from two to four and is important in catalytic chemistry, and +4 (eft), which is octahedral and much more strongly oxidizing than platinum (IV). The chemistry of palladium is similar to that of platinum, but palladium is between 103 to 5 x 10s more labile (192). A primary industrial application is palladium-catalyzed oxidation of ethylene (see Olefin polymers) to acetaldehyde (qv). Palladium-catalyzed carbon—carbon bond formation is an important organic reaction. 

The most common oxidation states and corresponding electronic configurations of platinum are +2 (d8), which is square planar, and +4 (< ), which is octahedral. Compounds in oxidation states between 0 ( °) and +6 (ct) exist. Platinum hydro station catalysts are used in the manufacture of silicone polymers. Several platinum coordination compounds are important chemotherapeutic agents used for the treatment of cancer. 

Electronic configuration 1. v22522/763 23/7 3 l04 24/764 /5.s 1. Ionic rad ius Ru4+ 0,60 A. Metallic radius 1,3251 A. First ionization potential 7.5 eV. Other physical properties of ruthenium will be found under Platinum and Platinum Group. See also Chemical Elements,... 

Ferrocene is only one of a large number of compounds of transition metals with the cyclopentadienyl anion. Other metals that form sandwich-type structures similar to ferrocene include nickel, titanium, cobalt, ruthenium, zirconium, and osmium. The stability of metallocenes varies greatly with the metal and its oxidation state ferrocene, ruthenocene, and osmocene are particularly stable because in each the metal achieves the electronic configuration of an inert gas. Almost the ultimate in resistance to oxidative attack is reached in (C5H5)2Co , cobalticinium ion, which can be recovered from boiling aqua regia (a mixture of concentrated nitric and hydrochloric acids named for its ability to dissolve platinum and gold). In cobalticinium ion, the metal has the 18 outer-shell electrons characteristic of krypton. 

The number of ligand donor atoms that surround a central metal ion in a complex is called the coordination number of the metal. Thus, platinum(II) has a coordination number of 4 in Pt(NH3)2Cl2, and iron(III) has a coordination number of 6 in [Fe(CN)6]3-. The most common coordination numbers are 4 and 6, but others are well known (Table 20.4). The coordination number of a metal ion in a particular complex depends on the metal ion s size, charge, and electron configuration, and on the size and shape of the ligands. 

Polynuclear platinum and palladium carbonyl clusters containing the bulky tri-ferf-butylphosphine ligand are inherently electron-deficient at the metal centers. The trigonal bipyramidal cluster [Pt3Re2(CO)6(P Bu3)3], as shown in Fig. 11.4.4(a), is electronically unsaturated with a deficit of 10 valence electrons, as it needs 72 valence electrons to satisfy an 18-electron configuration at... 

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