Samarium(III) oxide

Samarium(III) oxide

Names
Other names samarium sesquioxide
Identifiers
CAS Number	12060-58-1
ECHA InfoCard	100.031.845
CompTox Dashboard (EPA)	DTXSID30925575 DTXSID4051611, DTXSID30925575
Properties
Chemical formula	Sm2O3
Molar mass	348.72 g/mol
Appearance	yellow-white crystals
Density	8.347 g/cm3
Melting point	2335°C
Solubility in water	insoluble
Structure
Crystal structure	cubic
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Samarium(III) oxide (Sm₂O₃) is a chemical compound.

Uses

Samarium(II) 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 dehydration of acyclic primary alcohols to aldehydes and ketones. Another use involves preparation of other samarium salts.

Preparations

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

1. thermal decomposition of samarium(III) carbonate, 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.