Praseodymium(III) fluoride

Praseodymium(III) fluoride is an inorganic compound with the formula PrF3, being the most stable fluoride of praseodymium.

Preparation
The reaction between praseodymium(III) nitrate and sodium fluoride will obtain praseodymium(III) fluoride as a green crystalline solid:
 * Pr(NO3)3 + 3 NaF → 3 NaNO3 + PrF3

There are also literature reports on the reaction between chlorine trifluoride and various oxides of praseodymium (Pr2O3, Pr6O11 and PrO2), where praseodymium(III) fluoride is the only product. The reaction between bromine trifluoride and praseodymium oxide left in the air for a period of time also produces praseodymium(III) fluoride, but the reaction is incomplete; the reaction between praseodymium(III) oxalate hydrate and bromine trifluoride can obtain praseodymium(III) fluoride, and carbon is also produced from this reaction. Praseodymium(III) fluoride can also be obtained by reacting praseodymium oxide and sulfur hexafluoride at 584 °C.

Physical
Praseodymium(III) fluoride forms pale green crystals of trigonal system (or hexagonal system ), space group P 3c1, (or P 6/mcm ), cell parameters a = 0.7078 nm, c = 0.7239 nm, Z = 6, structure like cerium(III) fluoride (CeF3).

Chemical
Praseodymium(III) fluoride is a green, odourless, hygroscopic solid that is insoluble in water.

Uses
Praseodymium(III) fluoride is used as a doping material for laser crystals.