Ytterbium is considered to be moderately toxic.
Ytterbium is a bright, soft, silvery-white metal that is both ductile and malleable. It is a one of the rare earth metals. The metal tarnishes quickly in air and reacts slowly with water. It dissolves rapidly in mineral acids.
Isotope 160Yb is radioactive and is used in portable x-ray machines that need no electricity.
Under very high physical stress Ytterbium’s electrical resistance increases by an order of magnitude. It is therefore used in stress gauges to monitor ground deformations caused by earthquakes or underground explosions.
Ytterbium is used in alloys and is added to stainless steel to improve grain refinement and strength.
Ytterbium fiber laser amplifiers are used in marking and engraving. Ytterbium compounds are also used as catalysts in the organic chemical industry.