Tetrafluoroberyllate or orthofluoroberyllate is an anion with the chemical formula [BeF4]2−. It contains beryllium and fluorine. This fluoroanion has a tetrahedral shape, with the four fluorine atoms surrounding a central beryllium atom. It has the same size, charge, and outer electron structure as sulfate SO2−4. Therefore, many compounds that contain sulfate have equivalents with tetrafluoroberyllate. Examples of these are the langbeinites, and Tutton's salts.