Study of Hardness of Superhard Crystals by Topological Indices

Figure 1

Crystal structures of (a) , (b) , (c) , (d) , (e) , (f) , (g) , (h) , (i) , (j) , (k) , and (l) . Boron atoms are shown in orange.

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)

(j)

(k)

(l)