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Sigma KEE - Boron
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An element of group 13 of the periodic table. There are two allotropes, amorphous boron is a brown power, but metallic boron is black. The metallic form is hard (9.3 on Mohs' scale) and a bad conductor in room temperatures. It is never found free in nature. Boron-10 is used in nuclear reactor control rods and shields. It was discovered in 1808 by Sir Humphry Davy and by J.L. Gay-Lussac and L.J. Thenard.
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Parents ElementalSubstance The Class of PureSubstances that cannot be separated into two or more Substances by ordinary chemical (or physical) means. This excludes nuclear reactions. ElementalSubstances are composed of only one kind of atom. Examples: Iron (Fe), copper (Cu), and oxygen (O_2). ElementalSubstances are the simplest PureSubstances.


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