Erbium(III) bromide

Erbium(III) bromide
Names
IUPAC name
Erbium(III) bromide
Other names
Erbium tribromide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.033.526 Edit this at Wikidata
EC Number
  • 236-895-1
  • InChI=1S/3BrH.Er/h3*1H;/q;;;+3/p-3
    Key: GZTUDAKVGXUNIM-UHFFFAOYSA-K
  • Br[Er](Br)Br
Properties
ErBr3
Molar mass 406.971 g·mol−1
Appearance Violet crystalline solid
Melting point 923 °C (1,693 °F; 1,196 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Erbium(III) bromide is an inorganic compound of erbium and bromide, with the formula ErBr3. The anhydrous compound is a rose-violet, hygroscopic solid, while the hexahydrate, ErBr3·6H2O, forms pink crystals.

Preparation

Anhydrous erbium(III) bromide can be prepared from erbium(III) oxide using the ammonium-bromide route. In this method, the oxide is reacted with excess ammonium bromide, initially producing an ammonium bromide complex which decomposes on heating to give the anhydrous tribromide:

Er2O3 + 6 NH4Br → 2 ErBr3 + 6 NH3 + 3 H2O

The hexahydrate can be crystallized from an aqueous erbium bromide solution acidified with hydrobromic acid.

Properties

Anhydrous compound

Anhydrous ErBr3 is a rose-violet, hygroscopic crystalline solid.

It melts at about 923 °C according to modern compilations, although older measurements reported values near 950 °C. It is readily soluble in water but is moisture-sensitive in the anhydrous state.

Like other heavy rare-earth tribromides, molten ErBr3 has been investigated by neutron diffraction. The melt retains strong short-range Er–Br correlations but loses the long-range order of the crystalline phase.

Hexahydrate

Erbium(III) bromide hexahydrate, ErBr3·6H2O, forms pink crystals.

Brown, Fletcher and Holah studied the crystallographic properties of a series of lanthanide tribromide hexahydrates and showed that the hydrated bromides form structural families related to one another across the lanthanide series.

The hydrate readily loses water on heating, but direct dehydration is liable to produce erbium oxybromide rather than pure anhydrous ErBr3; this is why ammonium-halide methods are preferred for preparation of oxygen-free anhydrous material.

Reactions

Erbium(III) bromide reacts with lithium bromide at elevated temperature to form the ternary bromide Li3ErBr6:

ErBr3 + 3 LiBr → Li3ErBr6

Li3ErBr6 belongs to a family of lithium rare-earth bromides studied for their lithium-ion mobility.

References

  1. 1 2 Meyer, Gerd; Dötsch, Siegfried; Staffel, Thomas (1987). "The ammonium-bromide route to anhydrous rare earth bromides MBr3". Journal of the Less Common Metals. 127: 155–160. doi:10.1016/0022-5088(87)90372-9.
  2. 1 2 3 Brown, D.; Fletcher, S.; Holah, D. G. (1968). "The preparation and crystallographic properties of certain lanthanide and actinide tribromides and tribromide hexahydrates". Journal of the Chemical Society A: 1889–1894. doi:10.1039/J19680001889.
  3. ↑ Jantsch, G.; Jawurek, H.; Skalla, N.; Gawalowski, H. (1932). "Halides of the rare earths. VI. Halides of the terbium and erbium earth groups". Zeitschrift für anorganische und allgemeine Chemie. 207: 353–367.
  4. ↑ Wasse, J. C.; Salmon, P. S. (2000). "Structure of molten trivalent metal bromides studied by using neutron diffraction: the systems DyBr3, YBr3, HoBr3 and ErBr3". Journal of Physics: Condensed Matter. 12 (46): 9539–9552. doi:10.1088/0953-8984/12/46/302.
  5. 1 2 Bohnsack, Andreas; Balzer, Gert; Güdel, Hans-Ulrich; Wickleder, Mathias S.; Meyer, Gerd (1997). "Ternäre Halogenide vom Typ A3MX6. VII. Die Bromide Li3MBr6 (M = Sm–Lu, Y): Synthese, Kristallstruktur, Ionenbeweglichkeit". Zeitschrift für anorganische und allgemeine Chemie. 623 (9): 1352–1356. doi:10.1002/zaac.19976230905.