Caesium

Notable characteristics

The francium). Caesium is the least abundant of the five non-radioactive alkali metals. (Technically, francium is the least common alkali metal, but since it is highly radioactive with an estimated 30 grams in the entire Earth's crust at one time,^[1] its abundance can be considered zero in practical terms.)

Along with water and also reacts with ice at temperatures above −116 °C (−177 °F, 157 K).

sodium amide are stronger.

There is an account that caesium, reacting with fluorine and form traces of a higher fluoride such as CsF₃, analogous to XeF₂.

Applications

Probably the most widespread use of caesium today is in caesium formate-based drilling fluids for the oil industry. The high density of the caesium formate brine (up to 2.3 sg), coupled with the relative benignity of ¹³³Cs , reduces the requirement for toxic high-density suspended solids in the drilling fluid, which is a significant technological, engineering and environmental advantage. ^{[2] [3]}

Caesium is also notably used in atomic clocks, which are accurate to seconds in many thousands of years. Since 1967, the atom.

• ¹³⁴Cs has been used in ¹³⁷Cs, ¹³⁴Cs can be produced solely by nuclear reactions. ¹³⁵Cs has also been used in this function.
• Like other elements of group 1, caesium has a great affinity for oxygen and is used as a "getter" in vacuum tubes.
• This metal is also used in photoelectric cells due to its ready emission of electrons.
• Caesium was used as a propellant in early ion engines. It used a method of ionization to strip the outer electron from the propellant by simple contact with tungsten. Caesium use as a propellant was discontinued when Hughes Research Laboratory conducted a study finding Xenon gas as a suitable replacement.
• Caesium is used as a organic compounds.
• Radioactive isotopes of caesium are used in the medical field to treat certain types of cancer.
• fluoride ion.
• Caesium vapor is used in many common magnetometers.
• Because of their high density, caesium chloride solutions are commonly used in molecular biology for density gradient ultracentrifugation, primarily for the isolation of viral particles, subcellular organelles and fractions, and nucleic acids from biological samples.
• Caesium nitrate is used as silicon in infrared flares^[4] like the LUU-19 flare^[5], because it emits much of its light in the near infrared spectrum.
• Caesium-137 is an extremely common radioisotope used as a gamma-emitter in industrial applications such as:
  • moisture density gauges
  • leveling gauges
  • thickness gauges
  • well-logging devices (used to measure the thickness of rock-strata)
• Caesium is also used as an internal standard in spectrophotometry.
• Caesium has been used to reduce the radar signature of exhaust plumes in military aircraft.

History

Caesium (Latin caesius meaning "blueish grey" ^[6]) was spectrum analysis. The first caesium metal was produced in 1882 by Carl Setterberg. Historically, the most important use for caesium has been in research and development, primarily in chemical and electrical applications.

Occurrence

  An alkali metal, caesium occurs in silicate of aluminium and caesium) and within other sources. One of the world's most significant and rich sources of this metal is at Bernic Lake in Manitoba. The deposits there are estimated to contain 300,000 metric tons of pollucite at an average of 20% caesium.

It can be isolated by cyanide and in a number of other ways. Exceptionally pure and gas-free caesium can be made by the thermal decomposition of caesium azide. The primary compounds of caesium are nitrate. The price of caesium metal in 1997 was about US$30 per gram, but its compounds are much cheaper.

See also Caesium minerals.

Isotopes

Main article: isotopes of caesium

Caesium has at least 39 known isotopes, which is more than any other element except ³H. ¹³⁷Cs is produced from the detonation of nuclear weapons and is produced in nuclear power plants, and was released to the atmosphere most notably from the 1986 Chernobyl meltdown. It's because this isotope (¹³⁷Cs) is one of the numerous products of fission, directly issued from the fission of uranium.

Beginning in 1945 with the commencement of nuclear testing, ¹³⁷Cs was released into the radioactive fallout. Once ¹³⁷Cs enters the ground water, it is deposited on soil surfaces and removed from the landscape primarily by particle transport. As a result, the input function of these isotopes can be estimated as a function of time. Caesium-137 has a half-life of 30.17 years. It decomposes to barium-137m (a short-lived product of decay) then to a form of nonradioactive barium.

Precautions

All alkali metals are highly reactive. Caesium, being one of the heavier base, and can etch glass.

Caesium compounds are encountered rarely by most persons. All caesium compounds should be regarded as mildly toxic because of its chemical similarity to potassium. Large amounts cause hyperirritability and spasms, but such amounts would not ordinarily be encountered in natural sources, so Cs is not a major chemical environmental pollutant. Rats fed caesium in place of potassium in their diet die, so this element cannot replace potassium in function.

The isotopes ¹³⁴Cs and ¹³⁷Cs (present in the biosphere in small amounts as a result of radiation leaks) represent a radioactivity burden which varies depending on location. Radiocaesium does not accumulate in the body as effectively as many other fission products (such as radioiodine and radiostrontium), which are actively accumulated by the body.

See also

• Cs-137
• Goiânia accident, a major radioactive contamination incident involving a small rod of caesium chloride.
• Caesium compounds
• Dirty bomb

References

• Los Alamos National Laboratory - Cesium

Categories: Caesium