Borax $\left[\mathrm{Na}_{2}\left(\mathrm{B}_{4} \mathrm{O}_{5}(\mathrm{OH})_{4} \cdot 8 \mathrm{H}_{2} \mathrm{O}\right]\right.$

$\mathrm{Sp}^{2} \rightarrow$ trigonal planar

$\mathrm{Sp}^{3} \rightarrow$ tetrahedral

In borax $2\left(\mathrm{Sp}^{2}\right)$ trigonal planar and $2\left(\mathrm{Sp}^{3}\right)$ tetrahedral