It decomposes slowly in cold water and rapidly in hot water. Alkali solutions and dilute and concentrated acids attack the metal rapidly. The pure metal is likely to ignite if scratched with a knife. Cerium is a component of misch metal, which is extensively used in the manufacture of pyrophoric alloys for cigarette lighters.
While cerium is not radioactive, the impure commercial grade may contain traces of thorium, which is radioactive. The oxide is an important constituent of incandescent gas mantles and is emerging as a hydrocarbon catalyst in self cleaning ovens where it can be incorporated into oven walls to prevent the collection of cooking residues.
As ceric sulfate is used extensively as a volumetric oxidizing agent in quantitative analysis. Cerium compounds are used in the manufacture of glass, both as a component and as a decolorizer. Common chemical compounds are also provided for many elements. In addition technical terms are linked to their definitions and the menu contains links to related articles that are a great aid in one's studies.
A list of reference sources used to compile the data provided on our periodic table of elements can be found on the main periodic table page. Kenneth Barbalace. Periodic Table of Elements - Cerium - Ce.
Linking to this page If you would like to link to this page from your website, blog, etc. Promethium is an unstable, radioactive element which is only found on Earth in minute quantities in uranium ores.
Its existence was suspected for some time, because there was no known element with 61 protons in its nucleus, but there were no universally agreed-upon reports of its discovery until , when it was isolated by researchers who were separating and purifying uranium fission products at the Oak Ridge National Laboratory in Oak Ridge, Tennessee.
It is named for the Greek god Prometheus, who stole fire from the gods and gave it to mankind, and was punished by being chained to a rock and having his liver eaten by a eagle every day. The most stable isotope of the element, promethium, has a half-life of There are a number of other isotopes as well, but the majority of them have half-lives that are less than 30 seconds. Promethium is found in trace amounts in uranium ores, but because it is so unstable, it never accumulates above the concentration of about a picogram 10 g per ton of ore.
The spectral lines of promethium have also been observed in some stars. Promethium emits beta particles, and in the presence of elements of higher atomic weight can stimulate the release of X-rays.
It can be produced artificially by the bombardment of neodymium with neutrons to form neodymium, which decays into promethium and a beta particle. Because promethium is so unstable, it has few practical applications, but it is used as a beta-particle emitter for thickness gauges used for measuring the thickness of sheets of steel, in some luminous blue and green paints, and in miniature batteries used in guided missiles and pacemakers.
Samarium is a silvery metal. It is named for the mineral samarskite, from which it was first obtained. It is present in the Earth's crust at a concentration of 8 ppm, making it the 40th most abundant element. Samarium is used in alloys with cobalt to make strong permanent magnets which have a high resistance to demagnetization. It is also used in carbon-arc lights used in motion picture studios, as a neutron absorber in nuclear reactors, and in optical glass to absorb infrared light.
Europium is a soft, silvery-white metal. It is named for the continent of Europe. It is found in the Earth's crust at a concentration of 2 ppm, making it the 50th most abundant element. It is obtained from the ore monazite see introduction , which contains up to 2. Europium is used as in the red phosphor in the cathode-ray tubes in TVs and computer monitors.
Gadolinium is a soft, ductile, silvery-white metal. It is named for the mineral gadolinite, the first mineral containing rare earth elements to be discovered; gadolinite was in turned named after Johan Gadolin, the Swedish chemist who first investigated it. It is found in the Earth's crust at a concentration of 8 ppm, making it the 41st most abundant element. It is obtained from the ore monazite and bastnasite see introduction.
Gadolinium is relatively stable in dry air, but oxidizes in moist air and dissolves in water and acids. Gadolinium has a greater ability to absorb neutrons than any other element, primarily in the isotopes Gd and Gd Uses Its oxides are used in the optics and glass-making industries.
Sources Most abundant rare earth metal. Found in many minerals like monazite sand [Ce PO4 ]. Orbital configuration. Explore Other Lanthanides.
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