In the form of fluoroberyllate glass, it has the lowest refractive index for a solid at room temperature of 1.275.

Gaseous beryllium fluoride adopts a linear structure, with a Be-F distance of 143 pm.

The density of liquid BeF2 decreases near its freezing point, as Be2+ and F− ions begin to coordinate more strongly with one another, leading to the expansion of voids between formula units.

Heating purified (NH4)2BeF4 gives the desired product: In general the reactivity of BeF2 ions with fluoride are quite analogous to the reactions of SiO2 with oxides.

[citation needed] Beryllium fluoride is used in biochemistry, particularly protein crystallography as a mimic of phosphate.