What liquid is safe to sit on top of a 50% aqueous solution of Hydrofluoric acid?

Explanation of question: I want to put a liquid, (lets say an oil of some type), on top of a 50% concentration of Hydrofluoric acid and water.

I'd like the 2 liquids to be immiscible, just like oil and water are immiscible, where the oil floats on top of the water, I'd like a liquid to 'float' on the Hydrofluoric acid. I'd like to put a liquid on top of the HF solution so that it floats on the HF solution.
The problem is that HF is very reactive, so any idea what a suitable immiscible liquid would be?
Thanks for your help.

Why not, as you suggest, oil and water?
(What are you going to keep it in?)