Question

what is the correct name for MgF2?

Answer 1

Go to Wikipedia. Type "MgF2" into the search bar. You are taken to the following page which has the name of the compound:
http://en.wikipedia.org/wiki/MgF2

Alternatively, you could read up on naming conventions if you are working out of a textbook. It was in one of the first few chapters of my book.

Answer 2

magnesium floride

Answer 3

Magnesium fluoride

Answer 4

Most ionic compounds (metal - anything) are named for the metal anything-ide. Exceptions occur all the time, mostly with polyatomic ions. The answer is magnesium fluoride.