Europium(II) oxide

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Europium(II) oxide
Structure of Europium(II) oxide
Names
IUPAC name
Europium(II) oxide
Other names
Europium monoxide
Identifiers
3D model (
JSmol
)
ECHA InfoCard
 100.031.497 Edit this at Wikidata
EC Number
  • 234-660-8
  • InChI=1S/Eu.O
    Key: FYZGFASBNJXJGO-UHFFFAOYSA-N
  • [O-2].[Eu+2]
Properties
EuO
Molar mass 167.963 g/mol
Appearance Violet crystals[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Europium(II) oxide (EuO) is a chemical compound which is one of the oxides of europium. In addition to europium(II) oxide, there is also europium(III) oxide and the mixed valence europium(II,III) oxide.

Preparation

Europium(II) oxide can be prepared by the reduction of europium(III) oxide with elemental europium at 800 °C and subsequent vacuum distillation at 1150 °C.[2]

Eu2O3 + Eu → 3 EuO

It is also possible to synthesize from the reaction of europium oxychloride and lithium hydride.[3]

2 EuOCl + 2 LiH → 2 EuO + 2 LiCl + H2

In modern research, thin films can be manufactured by

molecular beam epitaxy directly from europium atoms and oxygen molecules. These films have contamination of Eu3+ of less than 1%.[4][5]

Properties

Europium(II) oxide is a violet compound as a bulk crystal and transparent blue in thin film form. It is unstable in humid atmosphere, slowly turning into the yellow

non-stoichiometric, containing up to 4% Eu3+ and small amounts of elemental europium.[6] However, since 2008 high purity crystalline EuO films can be created in ultra high vacuum conditions. These films have a crystallite size of about 4 nm.[citation needed
]

Europium(II) oxide is

Curie Temperature of 69.3 K. With the addition of about 5-7% elemental europium, this increases to 79 K.[2] It also displays colossal magnetoresistance, with a dramatic increase in conductivity below the Curie temperature. One more way to increase the Curie temperature is doping with gadolinium, holmium, or lanthanum.[6]

Europium(II) oxide is a semiconductor with a band gap of 1.12 eV.[6]

Applications

Because of the properties of europium(II) oxide, thin layers of the oxide deposited on silicon are being studied for use as spin filters. Spin filter materials only allow electrons of a certain spin to pass, blocking electrons of the opposite spin.[7]

References

  1. ISBN 3527306730
  2. ^
    ISSN 0021-8979
    .
  3. ^
    OCLC 310719490
    .
  4. S2CID 97016104
    .
  5. ISSN 1098-0121
    .
  6. ^
    hdl:1721.1/39538
    . Retrieved 2022-01-23.
  7. S2CID 22764388
    .
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