A compound containing only boron, nitrogen, and hydrogen was found to be 40.3% B, 52.2% N, and 7.5% H by mass. If 3.

A compound containing only boron, nitrogen, and hydrogen was found to be 40.3% B, 52.2% N, and 7.5% H by mass. If 3.301g of this compound is dissolved in 50g of benzene , the solution produced freezes at 1.30°C. If Kf for benzene is 5.12°C/m, and the freezing point of pure benzene is 5.48°C, what is the molecular weight of this  compound?  Besides please clear the molecular formula.