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  2. Metal allergy - Wikipedia

    en.wikipedia.org/wiki/Metal_allergy

    Nickel is the most common contact allergen worldwide (of people with contact dermatitis, 11.4% in Europe, 8.8–25.7% in China, and 17.5% in North America are allergic to nickel). [ 1 ] Nickel allergy, and contact allergies more generally, can develop when people are any age, but they are most likely to develop in early adulthood.

  3. Tantalum - Wikipedia

    en.wikipedia.org/wiki/Tantalum

    Tantalum halides span the oxidation states of +5, +4, and +3. Tantalum pentafluoride (TaF 5) is a white solid with a melting point of 97.0 °C. The anion [TaF 7] 2-is used for its separation from niobium. [41] The chloride TaCl 5, which exists as a dimer, is the main reagent in

  4. Group 5 element - Wikipedia

    en.wikipedia.org/wiki/Group_5_element

    There are 2 parts per million of tantalum in the Earth's crust, making it the 51st most abundant element there. 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 ...

  5. Tantalum pentoxide - Wikipedia

    en.wikipedia.org/wiki/Tantalum_pentoxide

    Tantalum pentoxide, also known as tantalum(V) oxide, is the inorganic compound with the formula Ta 2 O 5. It is a white solid that is insoluble in all solvents but is attacked by strong bases and hydrofluoric acid. Ta 2 O 5 is an inert material with a high refractive index and low absorption (i.e. colourless), which makes it useful for coatings ...

  6. Hardnesses of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Hardnesses_of_the_elements...

    Print/export Download as PDF; Printable version; In other projects Wikidata item; Appearance. move to sidebar hide ... tantalum: 6.5: 873–1200: 441-3430: 441–1224 ...

  7. Heavy metal element - Wikipedia

    en.wikipedia.org/wiki/Heavy_metal_(elements)

    An average 70 kg human body is about 0.01% heavy metals (~7 g, equivalent to the weight of two dried peas, with iron at 4 g, zinc at 2.5 g, and lead at 0.12 g comprising the three main constituents), 2% light metals (~1.4 kg, the weight of a bottle of wine) and nearly 98% nonmetals (mostly water).

  8. List of chemical elements - Wikipedia

    en.wikipedia.org/wiki/List_of_chemical_elements

    118 chemical elements have been identified and named officially by IUPAC.A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z).

  9. Isotopes of tantalum - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_tantalum

    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.