Here's how the name is derived:

* NH4+ is the ammonium ion.

* RhF6 is the hexafluororhodate(III) anion.

* Rh is the symbol for rhodium.

* F is the symbol for fluorine.

* 6 indicates six fluorine atoms.

* (III) indicates the +3 oxidation state of rhodium.

Therefore, the complete name is Ammonium Hexafluororhodate(III).