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Niobium is a chemical element; it has symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and ductile transition metal . Pure niobium has a Mohs hardness rating similar to pure titanium , [ 8 ] and it has similar ductility to iron .
Symbol Name Meaning SI unit of measure alpha: alpha particle: angular acceleration: radian per second squared (rad/s 2) fine-structure constant: unitless beta: velocity in terms of the speed of light c: unitless beta particle: gamma: Lorentz factor: unitless photon: gamma ray: shear strain: radian
Symbol [nb 1] Name Symbol Radiant energy: Q e [nb 2] joule: J: M⋅L 2 ⋅T −2: Energy of electromagnetic radiation. Radiant energy density: w e: joule per cubic metre J/m 3: M⋅L −1 ⋅T −2: Radiant energy per unit volume. Radiant flux: Φ e [nb 2] watt: W = J/s M⋅L 2 ⋅T −3: Radiant energy emitted, reflected, transmitted or ...
After the separation from the other minerals, the mixed oxides of tantalum Ta 2 O 5 and niobium Nb 2 O 5 are obtained. To produce niobium, the first step in the processing is the reaction of the oxides with hydrofluoric acid: [55] Ta 2 O 5 + 14 HF → 2 H 2 [TaF 7] + 5 H 2 O Nb 2 O 5 + 10 HF → 2 H 2 [NbOF 5] + 3 H 2 O
Mineral symbols (text abbreviations) are used to abbreviate mineral groups, subgroups, and species, just as lettered symbols are used for the chemical elements. The first set of commonly used mineral symbols was published in 1983 and covered the common rock-forming minerals using 192 two- or three-lettered symbols. [ 1 ]
[nb 1] Notes Name Symbol [nb 2] Name Symbol Luminous energy: Q v [nb 3] lumen second: lm⋅s T⋅J: The lumen second is sometimes called the talbot. Luminous flux, luminous power Φ v [nb 3] lumen (= candela steradian) lm (= cd⋅sr) J: Luminous energy per unit time Luminous intensity: I v: candela (= lumen per steradian) cd (= lm/sr) J ...
The table usually lists only one name and symbol that is most commonly used. The final column lists some special properties that some of the quantities have, such as their scaling behavior (i.e. whether the quantity is intensive or extensive ), their transformation properties (i.e. whether the quantity is a scalar , vector , matrix or tensor ...
Quantities, Units and Symbols in Physical Chemistry, also known as the Green Book, is a compilation of terms and symbols widely used in the field of physical chemistry. It also includes a table of physical constants , tables listing the properties of elementary particles , chemical elements , and nuclides , and information about conversion ...