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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.
Recent work has proposed zeolite-templated carbons (ZTCs) may be schwarzites. The name, ZTC, derives from their origin inside the pores of zeolites, crystalline silicon dioxide minerals. A vapor of carbon-containing molecules is injected into the zeolite, where the carbon gathers on the pores' walls, creating the negative curve.
Below 912 °C (1,674 °F), iron has a body-centered cubic (bcc) crystal structure and is known as α-iron or ferrite.It is thermodynamically stable and a fairly soft metal. α-Fe can be subjected to pressures up to ca. 15 GPa before transforming into a high-pressure form termed ε-Fe discussed below.
Meteoric iron was highly regarded due to its origin in the heavens and was often used to forge weapons and tools. [87] For example, a dagger made of meteoric iron was found in the tomb of Tutankhamun , containing similar proportions of iron, cobalt, and nickel to a meteorite discovered in the area, deposited by an ancient meteor shower.
Atomic oxygen, denoted O or O 1, is very reactive, as the individual atoms of oxygen tend to quickly bond with nearby molecules.Its lowest-energy electronic state is a spin triplet, designated by the term symbol 3 P.
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The history of science is often seen as a linear story of progress [27] but historians have come to see the story as more complex. [28] [29] [30] Alfred Edward Taylor has characterised lean periods in the advance of scientific discovery as "periodical bankruptcies of science". [31] Science is a human activity, and scientific contributions have ...
Gamow humorously decided to add the name of his friend—the eminent physicist Hans Bethe—to this paper in order to create the whimsical author list of Alpher, Bethe, Gamow, a play on the Greek letters α, β, and γ (alpha, beta, gamma).