= Solution
In a skeletal description, each of the four naked Sn atoms retains an outward lone pair and contributes two electrons to the framework. Each aryl-substituted Ge atom contributes three electrons after assigning one to its Ge–aryl bond; it is not assigned an additional spectator lone pair in this counting. Thus
$$
\boxed{N_{\rm skeletal}=4(2)+2(3)=14=2n+2\quad(n=6).}
$$
\b[The PSEP prediction is a six-vertex closo octahedron], with the two protected Ge vertices and four naked Sn vertices; distortion does not change the topological classification. The alternative gross delocalized count $6(4)-2=22$ is not a listed jellium shell closure. Subtracting a lone pair from every atom would incorrectly remove electrons from the substituted Ge framework and give the wrong classification.
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