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Between diamond and graphite: Diamond crystallizes in the cubic system but graphite crystallizes in the hexagonal system. 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 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.
The equilibrium pressure and temperature conditions for a transition between graphite and diamond is well established theoretically and experimentally. The pressure changes linearly between 1.7 GPa at 0 K and 12 GPa at 5000 K (the diamond/graphite/liquid triple point ).
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 ...
The equilibrium pressure and temperature conditions for a transition between graphite and diamond are well established theoretically and experimentally. The equilibrium pressure varies linearly with temperature, between 1.7 GPa at 0 K and 12 GPa at 5000 K (the diamond/graphite/liquid triple point).
The carbon allotropes diamond and graphite have vastly different properties; diamond is the hardest natural substance, has an adamantine lustre, and belongs to the isometric crystal family, whereas graphite is very soft, has a greasy lustre, and crystallises in the hexagonal family. This difference is accounted for by differences in bonding.
The Difference Between Lab-Grown and Real Diamonds Max Mumby/Indigo - Getty Images Marilyn Monroe once said that diamonds are a girl’s best friend, but we think she underestimated their ...
Although diamonds (top left) and graphite (top right) are identical in chemical composition—being both pure carbon—X-ray crystallography revealed the arrangement of their atoms (bottom). In diamond, the carbon atoms are arranged tetrahedrally and held together by single covalent bonds. By contrast, graphite is composed of stacked sheets.