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Percentage d character

Fig. 1. Catalytic activities of metals for ethane hydrogenolysis in relation to the percentage d character of the metallic bond. The closed points represent activities compared at a temperature of 205°C and ethane and hydrogen pressures of 0.030 and 0.20 atm, respectively, and the open points represent percentage d character. Three separate fields are shown in the figure to distinguish the metals in the different long periods of the periodic table. Fig. 1. Catalytic activities of metals for ethane hydrogenolysis in relation to the percentage d character of the metallic bond. The closed points represent activities compared at a temperature of 205°C and ethane and hydrogen pressures of 0.030 and 0.20 atm, respectively, and the open points represent percentage d character. Three separate fields are shown in the figure to distinguish the metals in the different long periods of the periodic table.
Fig. 7. Percentage d character of the metallic bond in copper-nickel alloys as a function of composition (74, 84). Fig. 7. Percentage d character of the metallic bond in copper-nickel alloys as a function of composition (74, 84).
Fig. 4. Hydrogen isotope exchange between C6H and C6D6. Correlation of randomisation rate constant kF, with percentage d-character of the metallic bonds (4). [Pg.146]

The articles by J. R. Anderson, J. H. Sinfelt, and R. B. Moyes and P. B. Wells, on the other hand, deal with a classical field, namely hydrocarbons on metals. The pattern of modem wTork here still very much reflects the important role in the academic studies of deuterium exchange reactions and the mechanisms advanced by pioneers like Horiuti and Polanyi, the Farkas brothers, Rideal, Tw igg, H. S. Taylor, and Turkevich. Using this method, Anderson takes ultrathin metal films with their separated crystallites as idealized models for supported metal catalysts. Sinfelt is concerned with hydrogcnolysis on supported metals and relates the activity to the percentage d character of the metallic bond. Moyes and Wells deal with the modes of chemisorption of benzene, drawing on the results of physical techniques and the ideas of the organometallic chemists in their discussions. [Pg.362]

Table 4.3. Natural bond angles (aacute and a0htUseA percentage d character, and hybrid concentration ( h max) of equivalent sd/l hybrids... Table 4.3. Natural bond angles (aacute and a0htUseA percentage d character, and hybrid concentration ( h max) of equivalent sd/l hybrids...
Table 4.3 summarizes the natural bond angles (aacute and obtuse), percentage d character, and concentration (Ihlmax) for various cases of equivalent sd/2 hybrids (including the sd1 case to be discussed below). [Pg.377]

According to these fractional weightings, the percentage d character of each Os—H bond hybrid is therefore expected to vary between 75 % (for sd3 hybrids, the covalent limit) and 66.7% (for sd2 hybrids, the ionic limit) with changing electronegativity of X ... [Pg.423]

Solution From (4.60a) and (4.60b), the estimated and actual percentage d characters of the Os—H and Os—X hybrids in each OsH3X compound are found to be... [Pg.425]

Figure 8.18 Correlation between catalytic activity of transition metals towards ethane hydrogenolysis and percentage d-character. The closed points represent activities and open points percentage d-character. (Following Sinfelt, 1977.)... Figure 8.18 Correlation between catalytic activity of transition metals towards ethane hydrogenolysis and percentage d-character. The closed points represent activities and open points percentage d-character. (Following Sinfelt, 1977.)...
Percentage d-character Considering the electronic structure of metals thus derived, Pauling then calculates the percentage d-character of the metallic bonds, the percentage d-character being an indication of bond strength. As examples, we have chosen cobalt, nickel and copper (Table I). [Pg.11]

Percentage d-Character of Cobalt, Nickel, and Copper (Pauling Theory (Brackets Indicate Bonding Orbitals ... [Pg.11]

Metal Outer electrons Reso- nance ratio Percentage d-character... [Pg.11]

A list of the percentage d-characters of the elements in the first, second and third long period is given in Table II. [Pg.12]

Percentage d-Character and Valency of the Transition Metals, According to Pauling Proc. Roy. Soc. A196, 343 (1949))... [Pg.12]

Similar work on acetylene hydrogenation (Sheridan and Reid (46)) has shown no clear relationship between percentage d-character and... [Pg.22]

Fig. 13. Relation between activation energy (NHs -f- D2) exchange reaction (Kemball) and percentage d character (Pauling). Fig. 13. Relation between activation energy (NHs -f- D2) exchange reaction (Kemball) and percentage d character (Pauling).
The percentage d character S can be calculated by using Equation 5-35. number of bonding d electrons x 100... [Pg.147]

Relationships have indeed been found between the percentage d character and the catal5dic activity, as we shall see for the hydrogenation of ethylene [T20]. However,... [Pg.147]

Activities sometimes correlate with the percentage d character of the metallic bonding, but there are many exceptions. [Pg.150]

The theory that the chemisorption bond is a covalence involving partially filled d-orbitals is not subject to quantitative test by calculation. Experimental correlations of heats of adsorption with the percentage d-character of the metal, particularly for adsorption of hydrogen on the transition metals, have led to taking the percentage d-character as a measure of unavailability of electrons in atomic d-orbitals and thus the expected strength of the chemisorption bond. For the alternative view in which the surface bond is... [Pg.164]

See other pages where Percentage d character is mentioned: [Pg.101]    [Pg.112]    [Pg.116]    [Pg.146]    [Pg.397]    [Pg.422]    [Pg.519]    [Pg.16]    [Pg.17]    [Pg.22]    [Pg.22]    [Pg.206]    [Pg.107]    [Pg.190]    [Pg.260]    [Pg.261]    [Pg.270]    [Pg.296]    [Pg.174]    [Pg.164]    [Pg.165]    [Pg.166]    [Pg.1557]    [Pg.122]   
See also in sourсe #XX -- [ Pg.147 , Pg.150 ]



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