Dysprosium perchlorate is an inorganic compound of dysprosium and the perchlorate ion, with the formula Dy(ClO4)3. It is known as an anhydrous salt and in hydrated forms, including the hexahydrate Dy(ClO4)3·6H2O. The anhydrous compound adopts the hexagonal structure characteristic of many rare-earth perchlorates.
Preparation Hydrated dysprosium perchlorate can be prepared by dissolving dysprosium(III) oxide in aqueous perchloric acid:
Dy2O3 + 6 HClO4 → 2 Dy(ClO4)3 + 3 H2O
Solutions used in modern spectroscopic work have been prepared directly from Dy2O3 and concentrated perchloric acid.
Dysprosium perchlorate hexahydrate has also been obtained by dissolving Dy2O3 in 50–60% perchloric acid, followed by removal of excess water under reduced pressure or by freeze-drying.
Anhydrous Dy(ClO4)3 can be obtained by controlled dehydration of hydrated dysprosium perchlorate.
Properties Anhydrous structure Anhydrous Dy(ClO4)3 crystallizes in the hexagonal crystal system, space group P63/m (No. 176).
It is isostructural with the anhydrous perchlorates of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Ho and Er, and belongs to a structure family related to the UCl3 type.
In this structure the Dy3+ centres are nine-coordinate. The coordination environment is formed by oxygen atoms belonging to perchlorate groups, which act as multidentate ligands and generate a three-dimensional channel-containing framework.
Across the lanthanide series, the lattice parameters decrease systematically because of the lanthanide contraction.
Hydrates and aqueous solution The hexahydrate Dy(ClO4)3·6H2O is a commonly used crystalline form.
In dilute aqueous solution, Dy3+ is strongly hydrated, while perchlorate behaves mainly as a weakly coordinating counterion.
Raman-spectroscopic studies of aqueous dysprosium perchlorate solutions support an inner hydration shell containing approximately eight to nine water molecules around Dy3+, with increasing ion pairing only at higher concentrations.
Thermodynamic measurements of aqueous rare-earth perchlorates likewise show that dysprosium perchlorate behaves as a strongly hydrated electrolyte, with non-ideal solution behavior arising from both hydration and ionic association.
Coordination chemistry Dysprosium perchlorate is used as a soluble source of Dy3+ in coordination and materials chemistry.
Reaction of Dy(ClO4)3·6H2O with thiocyanate salts and bulky organic cations has been used to prepare anionic dysprosium thiocyanate complexes such as [Dy(SCN)8]5−.
For example, [C16mim]5[Dy(SCN)8] has been prepared from dysprosium perchlorate hexahydrate, an imidazolium thiocyanate and KSCN.
Dysprosium perchlorate has also been used as a starting material for polynuclear Dy(III) coordination polymers exhibiting large magnetocaloric effects and slow magnetic relaxation.
Safety Dysprosium perchlorate is an oxidizing perchlorate salt and should be kept away from combustible and strongly reducing materials.
References