Ac Актиний 89 (227) 3 7 f 89 1050.0 3200.0 [Rn] 6d1 7s2 2 8 18 32 18 9 2 10.1 N/A Silver Cubic: Face centered 1.1 {"1":"499","2":"1170"} 499 3 1.88 22.5 0.12 12.0 1 21.7865 y 31.4311y BetaDecay Solid, Actinide, Radioactive, Natural ak-TIN-i-em Heavy, silvery-white, very radioactive metal It has no significant commercial applications. Extremely rare, found in all uranium ores. Usually obtained by treating radium with neutrons in a reactor. 0BlpjWBYW0k Actinium

Tantalum was discovered in Sweden in 1802 by Anders Ekeberg in the minerals tantalite from Finland and yttrotantalite from Sweden.

Unfortunately, William Hyde Wollaston claimed Ekeberg's new element was actually niobium, which had also been discovered in 1802.

In 1846, German chemist Heinrich Rose finally proved beyond doubt that tantalum and niobium were different elements. Назван в честь Тантала, героя греческой мифологии, отца Ниобы 89 1899 Andre Debierne France From the Greek word "aktinos" meaning "ray"

Tantalum is considered to be non-toxic

Tantalum occurs principally in the mineral columbite-tantalite

Tantalum is used in the electronics industry for capacitors and high power resistors.

The high melting point and oxidation resistance lead to the use of the metal in the production of vacuum furnace parts.

Tantalum oxide is used to make special glass with high index of refraction for camera lenses.