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Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in structure. If heated over 700 °C (1,292 °F) in air, diamond, being a form of carbon, oxidizes and its surface blackens, but the surface can be restored by re-polishing. [ 47 ]
Diamond is clear and transparent, but graphite is black and opaque. Diamond is the hardest mineral known (10 on the Mohs scale), but graphite is one of the softest (1–2 on Mohs scale). Diamond is the ultimate abrasive, but graphite is soft and is a very good lubricant. Diamond is an excellent electrical insulator, but graphite is an excellent ...
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.
Main diamond producing countries. Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic.Diamond as a form of carbon is tasteless, odourless, strong, brittle solid, colourless in pure form, a poor conductor of electricity, and insoluble in water.
Diamond and graphite materials and structure. Diamond is an allotrope of carbon where the atoms are arranged in a modified version of face-centered cubic (fcc) structure known as "diamond cubic". It is known for its hardness (see table above) and incompressibility and is targeted for some potential optical and electrical applications.
The extrapolated properties of lonsdaleite have been questioned, particularly its superior hardness, since specimens under crystallographic inspection have not shown a bulk hexagonal lattice structure, but instead a conventional cubic diamond dominated by structural defects that include hexagonal sequences. [12]
Another high-temperature lubricant, hexagonal boron nitride, has the same molecular structure as graphite. It is sometimes called white graphite, due to its similar properties. When a large number of crystallographic defects bind these planes together, graphite loses its lubrication properties and becomes what is known as pyrolytic graphite.
Although a computational study employing density functional theory methods reached the conclusion that as T → 0 K and p → 0 Pa, diamond becomes more stable than graphite by approximately 1.1 kJ/mol, [47] more recent and definitive experimental and computational studies show that graphite is more stable than diamond for T < 400 K, without ...
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