Symmetrical cleayage in diborane is given by :

Both symmetric and asymmetric cleavages can occur with diborane.

is symmetrically cleaved into two ${\mathrm{B}}_2{\mathrm{H}}_6$ fragments when large reagents are used.

${\mathrm{NH}}_3,{\mathrm{CH}}_3{\mathrm{NH}}_2$, and ${\left({\mathrm{CH}}_3\right)}_2\mathrm{NH}$cause symmetrical cleavage, but hydrolysis with small amines causes unsymmetrical cleavage, which is a cleavage leading to an ionic product.