Samarium oxide readily forms on the surface of samarium metal under humid conditions or temperatures in excess of 150°C in dry air.

The oxide is commonly white to off yellow in color and is often encountered as a highly fine dust like powder.

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.

[2] Samarium(III) oxide may be prepared by two methods: 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: Samarium(III) oxide dissolves in mineral acids, forming salts upon evaporation 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.