Lanthanide

Lanthanides are the series of chemical elements that comprises the 15 metallic chemical elements with atomic numbers 57 through 71, from lanthanum to lutetium. These elements along with the chemically similar elements scandium and yttrium are often collectively known as rare earth elements.

The lanthanides are not as rare as was once thought; even the scarce rare earths (e.g., europium, lutetium) are more common than the platinum-group metals. Several of the lanthanides form during the fission of uranium and plutonium.

Compoundsof lanthanides are used as catalysts in the production of petroleum and synthetic products. Lanthanides are used in lamps, lasers, magnets, phosphors, motion picture projectors, and X-ray intensifying screens. A pyrophoric mixed rare-earth alloy called Mischmetall (50% Ce, 25% La, 25% other light lanthanides) or misch metal is combined with iron to make flints for cigarette lighters. The addition of <1% Mischmetall or lanthanide silicides improves the strength and workability of low alloy steels.

Lanthanides share the various properties like: they are silvery- white metals that tarnish when exposed to air, forming their oxides, relatively soft metals, hardness increases somewhat with higher atomic number, moving from left to right across the period the radius of each lanthanide 3+ ion steadily decreases. This is refered to as “lanthanide contraction”.

Lanthanides react with water to liberate hydrogen, slowly in cold/ quickly upon heating. Lanthanides commonly bind to water. Lanthanides react in an exothermic reaction with H₂, lanthanides burns easily in air.React with water to liberate hydrogen (H₂), slowly in cold/quickly upon heating. Lanthanides commonly bind to water.React with H⁺ (dilute acid) to release H₂ (rapidly at room temperature