Dysprosium(III) chloride

Dysprosium(III) chloride (DyCl₃), 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, DyCl₃.6H₂O. Simple rapid heating of the hydrate causes partial hydrolysis^[1] to an oxychloride, DyOCl.

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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:

DyCl₃(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 DyCl₃(aq) + 3 H₂(g)

Dy₂(CO₃)₃(s) + 6 HCl(aq) → 2 DyCl₃(aq) + 3 CO₂(g) + 3 H₂O(l)

Anhydrous DyCl₃ 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 DyCl₃ in eutectic LiCl-KCl is electrolysed. The reduction occurs via Dy²⁺, 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.

References

1. ^ ^{a b c} F. T. Edelmann, P. Poremba, in: Synthetic Methods of Organometallic and Inorganic Chemistry, (W. A. Herrmann, ed.), Vol. 6, Georg Thieme Verlag, Stuttgart, 1997.
2. ^ M. D. Taylor, P. C. Carter, J. Inorg. Nucl. Chem. 24, 387 (1962); J. Kutscher, A. Schneider, Inorg. Nucl. Chem. Lett. 7, 815 (1971).
3. ^ L. F. Druding, J. D. Corbett, J. Am. Chem. Soc. 83, 2462 (1961); J. D. Corbett, Rev. Chim. Minerale 10, 239 (1973).
4. ^ Y. Castrillejo, M. R. Bermejo, A. I. Barrado, R. Pardo, E. Barrado, A. M. Martinez, Electrochimica Acta, 50, 2047-2057 (2005).