Samarium(III) oxide

Samarium(III) oxide (Sm2O3) is a chemical compound. Samarium oxide readily forms on the surface of samarium metal under humid conditions or temperatures in excess of 150°C in dry air. Similar to rust on metallic iron, this oxide layer spalls off the surface of the metal, exposing more metal to continue the reaction. The oxide is commonly white to off yellow in color and is often encountered as a highly fine dust like powder.

Samarium(III) oxide
Samarium(III) oxide
Names
IUPAC name
samarium(III) oxide
Other names
samarium sesquioxide, samaria
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.031.845
EC Number
  • 235-043-6
UNII
  • InChI=1S/3O.2Sm/q3*-2;2*+3 checkY
    Key: FKTOIHSPIPYAPE-UHFFFAOYSA-N checkY
  • O=[Sm]O[Sm]=O
  • [Sm+3].[Sm+3].[O-2].[O-2].[O-2]
Properties
Sm2O3
Molar mass 348.72 g/mol
Appearance yellow-white crystals
Density 8.347 g/cm3
Melting point 2,335 °C (4,235 °F; 2,608 K)
Boiling point Not Stated
insoluble
+1988.0·10−6 cm3/mol
Structure
Cubic, cI80
Ia-3, No. 206
Hazards
GHS labelling:
GHS07: Exclamation markGHS09: Environmental hazard
Warning
H319, H410
P264, P273, P280, P305+P351+P338, P337+P313, P391, P501
Related compounds
Other anions
 Samarium(III) chloride
Other cations
 Promethium(III) oxide, Europium(III) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)
Infobox references

Uses

Samarium(III) oxide is used in optical and infrared absorbing glass to absorb infrared radiation. Also, it is used as a neutron absorber in control rods for nuclear power reactors. The oxide catalyzes the dehydration and dehydrogenation of primary and secondary alcohols.[1] Another use involves preparation of other samarium salts. [2]

Preparations

Samarium(III) oxide may be prepared by two methods:

1. thermal decomposition of samarium(III) carbonate, hydroxide, nitrate, oxalate or sulfate:

Sm2(CO3)3 → Sm2O3 + 3 CO2

2. by burning the metal in air or oxygen at a temperature above 150 °C:

4 Sm + 3 O2 → 2 Sm2O3

Reactions

Samarium(III) oxide dissolves in mineral acids, forming salts upon evaporation and crystallization:

Sm2O3 + 6 HCl → 2 SmCl3 + 3 H2O

The oxide can be reduced to metallic samarium by heating with a reducing agent, such as hydrogen or carbon monoxide, at elevated temperatures.

References
  1. Catalytic properties of samarium oxide with respect to the dehydrogenation and dehydration of alcohols and the dehydrogenation of tetralin. Bulletin of the Academy of Sciences of the USSR, Division of chemical science, January 1964, Volume 13, Issue 1, pp 6–9.
  2. Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.