BrF - what is this

Hypophosphite - how is this represented with letter symbols

Fluorate - " "

BrF[math] is bromine fluoride. Fluorine is more electronegative than bromine, so it is the "anion" fluoride. It's just Fluorine, [math]F_2 or bromine, Br_2 that have had one atom replaced with the other.

Hypophosphite: H_2PO_2^-

Fluorate? Well, Chlorate is ClO_3^-, so I guess this would be analogous to that, FO_3^-. However, I don't believe I've ever heard of it. It's probably too unstable to exist.