Name: Anonymous 2010-05-10 1:34
#57, Lanthanum, La: The name derives from lanthano, the Greek word for to escape notice or be hidden, because it was years after the compound ceria was discovered that researchers noticed that ceria (impure) also contained another previously unknown compound (lanthana, i.e. lanthanum oxide).
For being similar to lanthanum, the elements cerium to lutetium on the periodic table are together with lanthanum called the lanthanide series. They (except promethium) are also historically linked with each other and with scandium and yttrium in their discovery in minerals first found in Sweden. Their oxide minerals were called rare earths, most of which were difficult to discover and isolate from each other.
Because lanthanides are so similar to each other, it is economical for many purposes to process the ores just enough to make alloys, called mischmetal, as a substitute for pure lanthanum. Mischmetal is mixed with iron and magnesium to make a type of ferrocerium (lighter flint), and mixed with any of nickel, cobalt, manganese, and aluminum to make an intermetallic compound for the most common kind of anodes in nickel-metal hydride batteries.
The compound lanthanum (III) oxide is added to glass to give it a higher refractive index, allowing for thinner lenses to have the power of thicker ones. (The Carl Zeiss brand Lantal glass is an example.)
For being similar to lanthanum, the elements cerium to lutetium on the periodic table are together with lanthanum called the lanthanide series. They (except promethium) are also historically linked with each other and with scandium and yttrium in their discovery in minerals first found in Sweden. Their oxide minerals were called rare earths, most of which were difficult to discover and isolate from each other.
Because lanthanides are so similar to each other, it is economical for many purposes to process the ores just enough to make alloys, called mischmetal, as a substitute for pure lanthanum. Mischmetal is mixed with iron and magnesium to make a type of ferrocerium (lighter flint), and mixed with any of nickel, cobalt, manganese, and aluminum to make an intermetallic compound for the most common kind of anodes in nickel-metal hydride batteries.
The compound lanthanum (III) oxide is added to glass to give it a higher refractive index, allowing for thinner lenses to have the power of thicker ones. (The Carl Zeiss brand Lantal glass is an example.)