Why are the 3 d - 5 d compounds CuAu and NiPt stable , whereas the 3 d - 4 d compounds CuAg and NiPd are not
نویسندگان
چکیده
We show that the existence of stable, ordered 3d-5d intermetallics CuAu and NiPt, as opposed to the unstable 3d-4d isovalent analogs CuAg and NiPd, results from relativity. First, in shrinking the equilibrium volume of the 5d element, relativity reduces the atomic size mismatch with respect to the 3d element, thus lowering the elastic packing strain. Second, in lowering the energy of the bonding 6s ,p bands and raising the energy of the 5d band, relativity enhances ~diminishes! the occupation of the bonding ~antibonding! bands. The raising of the energy of the 5d band also brings it closer to the energy of the 3d band, improving the 3d-5d bonding.
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Investigating the Effect of Changes of Halogenated Compounds on the Aromaticity Flow (NICS) of Composite Rings 5-fluorophenyl-1, 3, 7, 9-tetra methylpyrido [2,3-: d [d-5,6 dipyrimidine -2, 4, 6 and 8 tetron
In the combination of 5-fluorophenyl-1, 3, 7, 9-tetra methylpyrido [2, 3, d, d, 5, 6 dipyrimidine -2, 4, 6, and 8 tetron, there are 4 rings, respectively, ring that is attached to the halogen ring A and, respectively, a ring The lower and the right to the left of the ring A are called C, B, and D. Calculations and studies show that the amount of aromatics in halogen-ring A in all cases has the ...
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