The icosahedral h shell

What are the consequences of filling the / = 5 (h) shell on the geometry of Ceo The complete filling of the 1=5 state would lead to an accumulation of 72 JT electrons, assuming that all the 1=5 states are filled, before any 7=6 level is being occupied. In icosahedral symmetry, the 1=5 states split into the hu + flu + tzu irreducible representations (Table... 

The structure of the capsid (protein shell) for an icosahedral virus such as tomato bushy stunt virus. Pentons (P) are located at the 12 vertices of the icosahedron. Hexons (H), of which there are 20, form the edges and faces of the icosahedron. Each penton is composed of five protein subunits and each hexon is composed of six protein subunits. In all, the structure contains 180 protein subunits. 

Kroto, H. W. McKay, K. 1988 The formation of quasi-icosahedral spiral shell carbon particles. Nature, Lond. 331, 328. 

H. C. Longuet-Higgins and M. de V. Roberts, who predicted thereby that the icosahedron of 12 boron atoms familiar from elemental boron, boron carbide, and some borides should be stabilized in molecular hydride form, not as the neutral entity B Hu (which if icosahedral would be a diradical) but as the dianion [B12H12] , which contained the 25 valence shell electron pairs needed for the 12 exo B-H bonds and 13 skeletal bonding MOs. Subsequent MO treatments of the closo deltahedral anions B I 1 and carboranes (AB, 2H, in Figure 3.1 have shown that these are the shapes that make best bonding use of their (n + 1) pairs of electrons available for skeletal bonding. ... 

Zink, M., ScGrubmuller, H. (2009). Mechanical properties of the icosahedral shell of Southern bean mosaic virus A molecular dynamics study. Biophysical Journal, 96,1350. 

Cheng, R. H. et al. Fungal virus capsids, cytoplasmic compartments for the replication of double-stranded RNA, formed as icosahedral shells of assymetric Gag dimers. Journal of Molecular Biology 244, 255-258 (1994). 

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