Styx formalism

Styx formalism can be applied to charged structures as well, by hydrogenating them to get the neutral borane and then treating each B-H-B (s) as protonated B-B(y). For example, could be treated as B5H7. The styx code could be... 

Figure 5.10 Possible bonding schemes of BjH, based on styx formalism.

The Styx formalism and the more successful Wade s rules for the electronic requirement helped provide a yes/no answer for the existence of polyhedral borane clusters. But one should not overemphasize the importance of electron-counting rales. Molecules satisfying the same rale need not have the same thermodynamic stability. Electron-counting rules can be used as a tool for predicting the existence of molecules, but not for assessing their relative stability. Criteria based on electronic structure theory are required for evaluating the stability of molecules. Qualitative ideas can help in this process as well. The ring-cap orbital overlap compatibility is one such idea that connects the deltahedral boranes to aromatic hydrocarbons. 

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