Dysprosium(III) chloride


Dysprosium(III) chloride (DyCl<sub>3</sub>), also known as dysprosium trichloride, is a compound of dysprosium and chlorine. It is a white to yellow solid which rapidly absorbs water on exposure to moist air to form a hexahydrate, DyCl<sub>3</sub>.6H<sub>2</sub>O. Simple rapid heating of the hydrate causes partial hydrolysis[1] to an oxychloride, DyOCl.

Chemical properties

Dysprosium(III) chloride is a moderately strong Lewis acid, which ranks as "hard" according to the HSAB concept. Aqueous solutions of dysprosium chloride can be used to prepare insoluble dysprosium(III) compounds, for example dysprosium(III) fluoride:

DyCl<sub>3</sub>(aq) + 3 NaF(aq) → DyF3(s) + 3 NaCl(aq)

Preparation

Dysprosium(III) chloride can be prepared as a yellow aqueous solution by reaction of either dysprosium metal or dysprosium(III) carbonate and hydrochloric acid.

2 Dy(s) + 6 HCl(aq) → 2 DyCl<sub>3</sub>(aq) + 3 H2(g)

Dy2(CO3)3(s) + 6 HCl(aq) → 2 DyCl<sub>3</sub>(aq) + 3 CO2(g) + 3 H2O(l)

Anhydrous DyCl<sub>3</sub> can be made by dehydration of the hydrate either by slowly heating to 400 °C with 4-6 equivalents of ammonium chloride under high vacuum.[1][2] The anhydrous halide may alternatively be prepared from dysprosium metal and hydrogen chloride[3]. It is usually purified by high temperature sublimation under high vacuum.[1]

Uses

Dysprosium(III) chloride can be used as a starting point for the preparation of other dysprosium salts. Dysprosium metal is produced when a molten mixture of DyCl<sub>3</sub> in eutectic LiCl-KCl is electrolysed. The reduction occurs via Dy<sup>2+</sup>, at a tungsten cathode.[4]

Precautions

Dysprosium compounds are believed to be of low to moderate toxicity, although their toxicity has not been investigated in detail.

External links

Citations