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Tantalum is a chemical element; it has symbol Ta and atomic number 73. Previously known as tantalium, [citation needed] it is named after Tantalus, a figure in Greek mythology. [11] Tantalum is a very hard, ductile, lustrous, blue-gray transition metal that is highly corrosion-resistant.
Soil contains on average 1 to 2 parts per billion of tantalum, and seawater contains 2 parts per trillion of tantalum. A typical human contains 2.9 parts per billion of tantalum. Tantalum is found in the minerals tantalite and pyrochlore. [19] Dubnium does not occur naturally in the Earth's crust, as it has no stable isotopes. [78]
The mineral group tantalite [(Fe, Mn)Ta 2 O 6] is the primary source of the chemical element tantalum, a corrosion (heat and acid) resistant metal.It is chemically similar to columbite, and the two are often grouped together as a semi-singular mineral called coltan or "columbite-tantalite" in many mineral guides.
Natural tantalum (73 Ta) consists of two stable isotopes: 181 Ta (99.988%) and 180m Ta (0.012%). There are also 35 known artificial radioisotopes, the longest-lived of which are 179 Ta with a half-life of 1.82 years, 182 Ta with a half-life of 114.43 days, 183 Ta with a half-life of 5.1 days, and 177 Ta with a half-life of 56.56 hours.
A large fraction of the chemical elements that occur naturally on the Earth's surface are essential to the structure and metabolism of living things. Four of these elements (hydrogen, carbon, nitrogen, and oxygen) are essential to every living thing and collectively make up 99% of the mass of protoplasm. [1]
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These toxic elements are found naturally in the earth. They become concentrated as a result of human caused activities and can enter plant and animal (including human) tissues via inhalation, diet, and manual handling. Then, they can bind to and interfere with the functioning of vital cellular components.
Coltan is the colloquial name for the mineral columbite-tantalum ("col-tan"). In the early 21st century coltan mining is associated with human rights violations such as child labour, systematic exploitation of the population by governments or militant groups, exposure to toxic chemicals and other hazards as a result of lax environmental protection, and general safety laws and regulations. [1]