Cerium - Ce

Atomic number

58

Atomic mass

140.12 g.mol^-1

Electronegativity according to Pauling

1.1

Density

6.76 g.cm^-3at 20°C

Melting point

799 °C

Boiling point

3426 °C

Vanderwaals radius

0.181 nm

Ionic radius

0.102 nm (+3) ; 0,087 nm (+4)

Isotopes

9

Electronic shell

[ Xe ] 4f¹5d¹6s²

Energy of first ionisation

526.8 kJ.mol^-1

Energy of second ionisation

1045 kJ.mol^-1

Energy of third ionisation

1945.6 kJ.mol^-1

Energy of fourth ionisation

3537 kJ.mol^-1

Standard Potential

- 2.48 V ( Ce³⁺/ Ce )

Discovered by

W. von Hisinger in 1903

铈是一种罕见的化学物质,可以found in houses in equipment such as colour televisions, fluorescent lamps, energy-saving lamps and glasses. All rare chemicals have comparable properties.

Cerium is mostly dangerous in the working environment, due to the fact that damps and gasses can be inhaled with air. This can cause lung embolisms, especially during long-term exposure. Cerium can be a threat to the liver when it accumulates in the human body.

Cerium has no know biological role, but it has been noted that cerium salts stimulate metabolism.

Cerium is dumped in the environment in many different places, mainly by petrol-producing industries. It can also enter the environment when household equipment is thrown away. Cerium will gradually accumulate in soils and water soils and this will eventually lead to increasing concentrations in humans, animals and soil particles.

With water animals cerium causes damage to cell membranes, which has several negative influences on reproduction and on the functions of the nervous system.

Thanks to its use in catalytic converters cerium is slowly improving the atmosphere of cities, or wherever diesel engines operates. Diesel engines emits particulates, carbon particles only a few micrometers in diameter. One way to reduce particulates emissions is trap them in a ceramic filter and then burn them off. If a little cerium oxide is added to the fuel itself, it will catalyse the burning of the particulates and eliminate them.