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Black phosphorus is the thermodynamically stable form of phosphorus at room temperature and pressure, with a heat of formation of −39.3 kJ/mol (relative to white phosphorus which is defined as the standard state). [1] It was first synthesized by heating white phosphorus under high pressures (12,000 atmospheres) in 1914.
Although both are called "white phosphorus", in fact two different crystal allotropes are known, interchanging reversibly at 195.2 K. [5] The element's standard state is the body-centered cubic α form, which is actually metastable under standard conditions. [4] The β form is believed to have a hexagonal crystal structure. [5]
Phosphorus has several allotropes that exhibit strikingly diverse properties. [11] The two most common allotropes are white phosphorus and red phosphorus. [12] For both pure and applied uses, the most important allotrope is white phosphorus, often abbreviated WP. White phosphorus is a soft, waxy molecular solid composed of P 4 tetrahedra. This P
Phosphorus; Pronunciation / ˈ f ɒ s f ər ə s / (FOS-fər-əs) Allotropes: white, red, violet, black and others (see Allotropes of phosphorus) Appearance: white, red and violet are waxy, black is metallic-looking: Standard atomic weight A r °(P)
Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in crystalline structure.. Allotropy or allotropism (from Ancient Greek ἄλλος (allos) 'other' and τρόπος (tropos) 'manner, form') is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of the elements.
Fibrous red phosphorus is another crystalline form of red phosphorus. [7] It is obtained along with violet phosphorus when red phosphorus is sublimed in vacuum in the presence of iodine. [21] It is structurally similar to violet phosphorus. However, in fibrous red phosphorus, phosphorus chains lie parallel instead of orthogonal, unlike violet ...
Parts-per-million cube of relative abundance by mass of elements in an average adult human body down to 1 ppm. About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium ...
The general formula of a phosphoric acid is H n−2x+2 P n O 3n−x+1, where n is the number of phosphorus atoms and x is the number of fundamental cycles in the molecule's structure; that is, the minimum number of bonds that would have to be broken to eliminate all cycles.