A fluoroberyllate is a compound of fluorine and beryllium with other elements. The main kinds are the tetrafluoroberyllates (BeF4)2−, the trifluoroberyllates (equivalent to BeF3)−, polymeric fluoroberyllates (which can crystallise in the same form as silica containing minerals) and fluoroberyllate glass.
References
Fluoroberyllate Wikipedia(Text) CC BY-SA