Trigonal prismatic cluster

Electronic Structure of Polynuclear Technetium Clusters 5.3.1 Trigonal-Prismatic Clusters... 

The electronic structure of trigonal-prismatic technetium clusters was discussed in [142]. The main results obtained in this work are considered below. 

Fig. 11. Results of EHT calculations of technetium trigonal-prismatic clusters...

The long-wavelength IR spectra of trigonal prismatic technetium clusters and a number of unusual physico-chemical properties of the clusters with ferrieinium cations [108] support the latter assumption. The discovered properties of the clusters with ferrieinium cations may be accounted for by the formation of the conductivity bands and, probably, hard-fermion bands in these compounds by the 5s(5p)-AO s of technetium atoms and 4s(4p)-AO s of the iron atoms. The formation of these bands may be supported by the following facts the ESR spectra of these compounds with geft close to that of a free electron temperature independent conductivity and an unusual temperature dependence of the Mossbauer and X-ray photoelectron spectra [108]. 

HOMO-LUMO. This may be supported by low Zeff of technetium atoms in tetragonal-prismatic clusters [103,127] and formation of compounds with fer-ricinium cations with some unusual physico-chemical properties, as is the case of trigonal-prismatic clusters [108,128]. 

To conclude this section, we consider one more probable way for the stabilization of octahedral clusters, which, as was shown in the previous section, is characteristic of binuclear, trigonal-prismatic and, obviously, all types of technetium acido-clusters [10]. According to [12,77], all technetium clusters with an odd number of metallic electrons have shorter multiple M-M bonds than those in analogous structures, but with an even number of metallic electrons. In our opinion [10, 15], this effect of an odd number of metallic electrons is essentially analogous to the effect of the increase in M-M bond... 

Heptanuclear Trigonal Prismatic Clusters Stabilized by Monodentate Imidazole Ligand... 

The versatile binding modes of the Cu2+ ion with coordination number from four to six due to Jahn-Teller distortion is one of the important reasons for the diverse structures of the Cu-Ln amino acid complexes. In contrast, other transition metal ions prefer the octahedral mode. For the divalent ions Co2+, Ni2+, and Zn2+, only two distinct structures were observed one is a heptanuclear octahedral [LnM6] cluster compound, and the other is also heptanuclear but with a trigonal-prismatic structure. 

Scheme 4 Formation of the heptanuclear trigonal prismatic clusters 17-22...

Fig. 18 Heptanuclear trigonal prismatic clusters with amino acids as ligands...

Fig. 19 Possible structure of the mother species I,nNifi(gly)fi(p3 0n)3(n20)fi( j.2 OH2 )3 ]61 an

The 90 electron trigonal prismatic cluster, [Rh C(CO) ], is electron rich and seems to behave as though there is a pair of electrons pointing out of each triangular face. Each metal atom is surrounded by five groups (1 terminal CO, 3 bridging CO s and the interstitial carbide) in an essentially square pyramidal... 

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