Barium.

barium - silvery-white ductile metal. It splits when it hits hard. There are two allotropic modifications of barium: up to 375 ° C stable α-Ba with a cubic volume-centered lattice (parameter a = 0.501 nm), higher stable β-Ba.

Hardness on the mineralogical scale of 1.25; on the Mohs scale 2.

Store metal barium in kerosene or under a layer of paraffin.

Application

Metal barium, often alloyed with aluminum, is used as a gas absorber (getter) in high-vacuum electronic devices.
Anti-corrosion material

Barium is added together with zirconium in liquid metal coolants (alloys of sodium, potassium, rubidium, lithium, cesium) to reduce the aggressiveness of the latter to pipelines, and in metallurgy.
ferroelectric and piezoelectric

Barium titanate is used as a dielectric in the manufacture of ceramic capacitors, as well as a material for piezoelectric microphones and piezoceramic emitters.

Optics
Barium fluoride is used in the form of single crystals in optics (lenses, prisms).

Pyrotechnics
Barium peroxide is used for pyrotechnics and as an oxidizer. Barium nitrate and barium chlorate are used in pyrotechnics to color a flame (green fire).

Atomic and hydrogen energy
Barium chromate is used in the production of hydrogen and oxygen by thermochemical method (Oak Ridge cycle, USA).

High Temperature Superconductivity

Barium oxide together with copper and rare earth metal oxides is used for the synthesis of superconducting ceramics operating at a temperature of liquid nitrogen and above.