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  Lanthanum

Sigma KEE - Lanthanum

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Lanthanum
(From the Greek word lanthanein, to line hidden) Silvery metallic element belonging to group 3 of the periodic table and oft considered to be one of the lanthanoids. Found in some rare-earth minerals. Twenty-five natural isotopes exist. La-139 which is stable, and La-138 which has a half-life of 10^10 to 10^15 years. The other twenty-three isotopes are radioactive. It resembles the lanthanoids chemically. Lanthanum has a low to moderate level of toxicity, and should be handled with care. Discovered in 1839 by C.G. Mosander.
Relationships      
Parents substance �l�mentaire 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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