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At normal temperature and pressure, 20 °C (293 K) and 1 standard atmosphere (0.10 MPa), the stable phase of carbon is graphite, but diamond is metastable and its rate of conversion to graphite is negligible. [28] However, at temperatures above about 4500 K, diamond rapidly converts to graphite.
During a fire the graphite intumesces (expands and chars) to resist fire penetration and prevent the spread of fumes. A typical start expansion temperature (SET) is between 150 and 300 °C. Graphite's specific gravity is 2.3, which makes it less dense than diamond. Graphite is slightly more reactive than diamond.
At standard temperature and pressure, 20 °C (293 K) and 1 standard atmosphere (0.10 MPa), the stable phase of carbon is graphite, but diamond is metastable and its rate of conversion to graphite is negligible. [7] However, at temperatures above about 4500 K, diamond rapidly converts to graphite.
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 ]
A Assuming an altitude of 194 metres above mean sea level (the worldwide median altitude of human habitation), an indoor temperature of 23 °C, a dewpoint of 9 °C (40.85% relative humidity), and 760 mmHg sea level–corrected barometric pressure (molar water vapor content = 1.16%). B Calculated values *Derived data by calculation.
The delocalization also accounts for the energetic stability of graphite over diamond at room temperature. Some allotropes of carbon: a) diamond; b) graphite; c) lonsdaleite; d–f) fullerenes (C 60, C 540, C 70); g) amorphous carbon; h) carbon nanotube
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.
Diamond: 1000 [5] Fiberglass or foam-glass ... temperatures are constant, and radial heat loss is prevented or minimized. ... Graphite, natural 25-470 [85] 146-246 ...