Libreville is its capital (5)
I believe the answer is:
gabon
'libreville is its capital' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for gabon that I've seen before include "W. Afr. equatorial state" , "Republic on the west coast of Africa" , "French spoken here" , "W. African country" , "state of Africa" .)