Actinium(III) fluoride (AcF₃) is an

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...

, a salt of

actinium Actinium is a chemical element with the symbol Ac and atomic number 89. It was first isolated by Friedrich Oskar Giesel in 1902, who gave it the name ''emanium''; the element got its name by being wrongly identified with a substance And ...

and

fluorine Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reacti ...

Synthesis

Actinium fluoride can be prepared in solution or by a solid-state reaction. In the first method,

actinium hydroxide Actinium is a chemical element with the symbol Ac and atomic number 89. It was first isolated by Friedrich Oskar Giesel in 1902, who gave it the name ''emanium''; the element got its name by being wrongly identified with a substance And ...

is treated with

hydrofluoric acid Hydrofluoric acid is a Solution (chemistry), solution of hydrogen fluoride (HF) in water. Solutions of HF are colourless, acidic and highly Corrosive substance, corrosive. It is used to make most fluorine-containing compounds; examples include th ...

and the product precipitates: :Ac(OH)3 + 3HF -> AcF_3(v) + 3H2O In the solid-state reaction, actinium metal is treated with

hydrogen fluoride Hydrogen fluoride (fluorane) is an inorganic compound with the chemical formula . This colorless gas or liquid is the principal industrial source of fluorine, often as an aqueous solution called hydrofluoric acid. It is an important feedstock i ...

gas at 700 °C in a platinum crucible.Meyer, Gerd and Morss, Lester R. (1991) ''Synthesis of lanthanide and actinide compounds.'' Springer. . pp. 87–88

Properties

Actinium fluoride is a white solid that reacts with ammonia at 900–1000 °C to yield an actinium oxyfluoride: :AcF3 + 2NH3 + H2O -> AcOF + 2NH4F While lanthanum oxyfluoride is easily formed by heating

lanthanum fluoride Lanthanum trifluoride is a refractory ionic compound of lanthanum and fluorine. The LaF3 structure Bonding is ionic with lanthanum highly coordinated. The cation sits at the center of a trigonal prism. Nine fluorine atoms are close: three a ...

in air, a similar treatment merely melts actinium fluoride and does not yield AcOF.

References

{{Authority control Actinium compounds Fluorides Actinide halides