Metal cerium

The English name is Cerium

Specification or purity ingot,1-10mm, held in oil, 99.5% metals basis

Transport conditions Conventional transport

General description

It is prone to oxidation and spontaneous combustion in air and must be kept in paraffin or mineral oil. It is a kind of lanthanide metal with the highest natural abundance and lively nature. Tarnish in air, burn when heated, react quickly with water, dissolve in acid. For rare earth magnetic materials, special steel and nonferrous metal alloy additives, can also be used as hydrogen storage materials, electric storage materials, etc. Used for making alloys; Magnets for processing. Used in the manufacture of glass, flint, ceramics and alloys.
 

The CAS number is 7440-45-1

Melting point 815°C

Boiling point 3257°C

Storage temperature filled with argon

MDL number MFCD00010924

Density 6.67

Molecular weight 140.12

Molecular formula Ce

EC No. 231-154-9

Brand Aladdin

PubChem CID 23974

Cerium is one of 17 rare earth metals (including scandium, yttrium, and lanthanum to lutetium in the lanthanide series). Despite its name as a "thin" earth metal, cerium is quite abundant and is only slightly less abundant than copper in the earth's crust. Element 58 is more common in modern life than it might seem. Hydrogrout containing cerium soil (cerium dioxide) is used for chemical mechanical polishing of the surfaces of microelectronic devices wafers, electronic displays, eyeglasses and other optical materials. By chemically reacting with alkaline sites on the surface of the material, ceric soil can provide better polishing rates than simple mechanical methods.

Many applications of cerium are based on the conversion of oxidation states between cerium (which has one 4f electron) and cerium (which has zero 4f electrons), which is also a fairly unique property among rare earth metals. The REDOX chemistry of cerium (III/IV) allows its oxides to store and release oxygen, so cerium oxides can be used for heterogeneous catalysis. The non-stoichiometric cerium oxide system CeO2−x has an unusually high ionic mobility, due in part to the oxygen vacancy in its lattice octahedron.

Cerium oxide can also be used to facilitate industry-important water-gas conversion reactions, and it is also used in solid-oxide fuel cells. Hydrocarbon fuels encounter element 58 at the beginning and end of their life cycle: zeolite (octahedral zeolite) impregnated with cerium and lanthanum can be used as a catalyst for oil cracking during refining; Harmful fuel exhaust is converted into nitrogen, carbon dioxide and water in the car's three-way catalyst converter, which uses cerium oxide and precious metals. Because of the absorption of reactive oxygen species, cerium oxide nanoparticles are being explored for medical applications in antioxidant therapy.

For synthetic chemists, cerium is commonly found in ammonium cerium nitrate (CAN) as a powerful oxidant. This is an extreme "nuclear option" in oxidation. In contrast to the utility of cerium oxide and the single electron oxidizer ammonium cerium nitrate which is widely used in both organic and inorganic chemistry, the coordination chemistry and organometallic chemistry of cerium have not been particularly developed.

The process of oxidizing a cerium coordination compound to a cerium tetravalent product and then efficiently separating the product is surprisingly difficult. This may lead to the lack of studies on cerium coordination compounds. One possible reason for this difficulty is the low rate of these oxidation reactions, which in turn is due to the indispensability of steric hindrance in the preparation of discrete complexes containing individual ceric cations.

Recently, our group has solved this problem by attempting to control the metal coordination range with dissimilar binuclear metal complexes (the general structure is shown in the figure). Flexible chains of lithium cations and aromatic ether ligands surround the cerium atom and keep it accessible, allowing for quick and easy conversion of cerium atom to cerium. This result supports the view that cerium oxidation is controlled by kinetics.