To calculate its molar mass, we need the atomic masses of boron and silicon:

* Boron (B): 10.811 g/mol

* Silicon (Si): 28.085 g/mol

Now, we can calculate the molar mass of hexaboron silicide:

Molar mass of B₆Si = (6 * 10.811 g/mol) + (1 * 28.085 g/mol)

= 64.866 g/mol + 28.085 g/mol

= 92.951 g/mol

Therefore, the molar mass of hexaboron silicide is 92.951 g/mol.