Heavy Atom Group Elements

Abboud et al. focused on the P4... Li+ ion in the gas phase, which they colourfully described as a planetary system. Protonation of gaseous tetraphos-phorus P4(g) lead to a new chemical bond, the essentially covalent 2e-3c bond P... H... P. From AIM they learnt about the fimdamental differences between the nature of the interactions of P4with H+ and Li+. In the former the P-H bonds formed are covalent, while the interactions with Li+ are essentially electrostatic. 

Partially triggered by the atmospheric interest of metal carbides Barrientos et 

Zanehini performed a computational study on the kinetic behaviour of the cyano-isocyano isomerization and the nature of the transition states of relevant Si and C containing compounds. In the silylcyanides a type of AIM bond order was computed to be half of the bond order values of the cyanides. This unexpected result could contribute to rationalization of the calculated values of the isomerization energy, indicating a larger ionic character in the Si compounds. 

In view of their interest in the stabilization in neutral bicyclic sulfoxide compounds El-Bergmi et al. performed B3LYP/6-3H-G calculations on 5-thiabicyclo[2.1.1]hex-2-ene 5-oxide derivatives. The GIAO method and AIM revealed a stabilization of the S atom with the double bond for the exo configuration, in agreement with the experimental results. 

Allen et al. joined a lively debate on the bond order of certain recently synthesized GaGa and GeGe bonds. They argued that while any analysis of the calculated electron density is arbitrary, one of the most self-defining was AIM. The calculation of an AIM bond order for Zra/w-MeGeGeMe yielded a GeGe covalent bond order of 2.097, which is reasonably close to 2. They computed bond orders for other model systems and compared results with MO interpretations. 

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The importance of scalar relativistic effects for compounds of transition metals and/or heavy main group elements is well established by now [44], Somewhat surprisingly (at first sight), they may have nontrivial contributions to the TAE of first-row and second-row systems as well, in particular if several polar bonds to a group VI or VII element are involved. For instance, in BF3, S03) and SiF4, scalar relativistic effects reduce TAE by 0.7, 1.2, and 1.9kcal/mol, respectively - quantities which clearly matter even if only chemical accuracy is sought. Likewise, in a benchmark study on the electron affinities of the first-and second-row atoms [45] - where we were able to reproduce the experimental values to... 

Mathematical cluster chemistry/Metal-metal interactions in transition metal clusters with donor ligands/Electron count versus structural arrangement in clusters based on a cubic transition metal core with bridging Main Group elements/Metalloboranes/ Clusters with interstitial atoms from the p-block How do Wade s rules handle them /Diverse naked clusters of the heavy Main Group elements Electronic regularities and analogies... 

The resulting count of 40 electrons per Teg units (i.e., 4x6 electrons for the Te° squares and 2x8 electrons for the two terminal Te atoms of the Teg" chains) corresponds to the observed [Te "] formulation for the component polytelluride sheets of Cs4Te2g. An alternative way of deriving the preferred electron count for networks of heavy main group elements consisting of finite-length linear chains is to employ an electron-rich multicentre bonding... 

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