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Transition-group complexes, forbidden transitions symmetry

The value of this energy spacing between the groups of d-orbitals can be calculated (19B) from the spectra of the ions and the free atoms. In fact the visible spectra of the simple complexes of the transdtion metal ions is largely due to excitation of these d-electrons. The extinction coefficients are often very small since the transitions are forbidden by symmetry and electron pairing selection rules. [Pg.561]

In the point-group Td, p-orbitals transform in the same way as dxy, dyt, and dtx, owing to the absence of a center of symmetry. This has the important consequence that all six orbitals are mixed together and the electronic transitions have some d-p character they are therefore not forbidden and have higher intensities than the nearly pure d-d transitions of octahedral complexes. [Pg.151]

The d-d bands are usually relatively low in intensity compared to CT bands contrast the palish hues of familiar salts of Cr, Mn, Fe, Co, Ni, and Cu with the intense purple of Mn04. This can be explained within the CF model. The probability of a transition is governed by selection rules see Group Theory). In atomic spectra, transitions between states having the same / quantum number are forbidden if this rule were strictly obeyed, d-d transitions should not be observable. Moreover, if there is a center of symmetry, as in an octahedral or square coplanar complex, d-d transitions are forbidden although they can be observed, albeit relatively weakly. Molecular vibration can disturb the center of synunetry, and Vibronic Coupling lends intensity to d d absorption. A tetrahedral complex has no center of synunetry and the... [Pg.2386]


See other pages where Transition-group complexes, forbidden transitions symmetry is mentioned: [Pg.243]    [Pg.282]    [Pg.1106]    [Pg.295]    [Pg.225]    [Pg.78]    [Pg.45]    [Pg.2945]    [Pg.290]    [Pg.24]    [Pg.607]    [Pg.53]    [Pg.127]    [Pg.361]    [Pg.119]    [Pg.83]    [Pg.41]    [Pg.18]    [Pg.37]    [Pg.331]    [Pg.139]    [Pg.202]    [Pg.2385]    [Pg.47]    [Pg.143]    [Pg.218]    [Pg.88]    [Pg.294]    [Pg.374]    [Pg.206]    [Pg.231]   
See also in sourсe #XX -- [ Pg.36 , Pg.43 , Pg.45 , Pg.48 ]




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Complex symmetry

Forbidden

Forbidden transition

Group symmetry

Symmetry forbidden

Symmetry-forbidden transitions

Transition Group

Transition-group complexes, forbidden transitions

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