Aromaticity/antiaromaticity Group 13 metal atoms

Finally, the concept of aromaticity and antiaromaticity in compounds that feature rings of metal atoms is discussed by Tsipis, who focuses on rings of main group metal atoms, and by Boldyrev et al., who focus on transition metal compounds. 

In this chapter, we focus on aromaticity and antiaromaticity in inorganic compounds only. It means that the chemical species, which will be discussed, do not contain carbon atoms in their cyclic structures. There are a few review articles [17-25], which discuss different aspects of aromaticity and antiaromaticity in inorganic chemistry. Before we go further, we would like to outline the structure of this chapter. First, we describe criteria that are commonly used for probing aromaticity. Second, we consider inorganic aromatic molecules, which we loosely call conventional aromatic molecules. These molecules are simply isoelectronic species to one of the organic aromatic molecule. Third, we focus on what we loosely call unconventional aromatic molecules composed of main group atoms and transition-metal atoms. Finally, we conclude the chapter with a summary and short outlook. 

Aromatic/Antiaromatic Three-Membered Rings of Group 1 Metal Atoms. 226... 

Another family of aromatic/antiaromatic three-membered rings of metal atoms concerns the 13 group elements (Al, Ga, In, and Tl). Kuznetsov and Boldyrev [88] reported theoretical evidence of double (a -i- jt) aromaticity in [c-Xs]" (X = B, Al, Ga) species. The [c-Xj]" clusters should be considered as earlier electron-deficient double aromatic systems, because their k-MOs are occupied earlier than in... 

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