Step 1: Understanding the icosahedral closo-borane.
An icosahedral closo-borane has a polyhedral structure consisting of 12 vertices, corresponding to the number of boron atoms in the cluster. The icosahedron is a symmetrical polyhedron with 12 vertices, 30 edges, and 20 faces.
Step 2: Conclusion.
The number of vertices in an icosahedral closo-borane is 12.