Samarium(III) oxide
Encyclopedia
Samarium oxide (Sm2
O3
) is a chemical compound
.
absorber in control rods for nuclear power reactors. The oxide catalyzes dehydration of acyclic primary alcohol
s to aldehyde
s and ketone
s. Another use involves preparation of other samarium salts.
1. thermal decomposition
of samarium(III) carbonate, hydroxide, nitrate, oxalate or sulfate:
2. by burning the metal in air or oxygen at a temperature above 150 °C:
and crystallization
:
The oxide can be reduced to metallic samarium by heating with a reducing agent
, such as hydrogen or carbon monoxide
, at elevated temperatures.
Samarium
Samarium is a chemical element with the symbol Sm, atomic number 62 and atomic weight 150.36. It is a moderately hard silvery metal which readily oxidizes in air. Being a typical member of the lanthanide series, samarium usually assumes the oxidation state +3...
O3
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
) is a chemical compound
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
.
Uses
Samarium(III) oxide is used in optical and infrared absorbing glass to absorb infrared radiation. Also, it is used as a neutronNeutron
The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...
absorber in control rods for nuclear power reactors. The oxide catalyzes dehydration of acyclic primary alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
s to aldehyde
Aldehyde
An aldehyde is an organic compound containing a formyl group. This functional group, with the structure R-CHO, consists of a carbonyl center bonded to hydrogen and an R group....
s and ketone
Ketone
In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...
s. Another use involves preparation of other samarium salts.
Preparations
Samarium(III) oxide may be prepared by two methods:1. thermal decomposition
Thermal decomposition
Thermal decomposition, or thermolysis, is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes....
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 evaporationEvaporation
Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....
and crystallization
Crystallization
Crystallization is the process of formation of solid crystals precipitating from a solution, melt or more rarely deposited directly from a gas. Crystallization is also a chemical solid–liquid separation technique, in which mass transfer of a solute from the liquid solution to a pure solid...
:
- Sm2O3 + 6 HCl → 2 SmCl3 + 3 H2O
The oxide can be reduced to metallic samarium by heating with a reducing agent
Reducing agent
A reducing agent is the element or compound in a reduction-oxidation reaction that donates an electron to another species; however, since the reducer loses an electron we say it is "oxidized"...
, such as hydrogen or carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
, at elevated temperatures.