The spelling of the chemical element represented by the symbol Cs is "caesium" in British English and "cesium" in American English. The IPA phonetic transcription of "caesium" is /ˈsiːziəm/, where the first syllable is pronounced like the word "see" and the second syllable is pronounced like "zee-um". This spelling follows the convention of using "ae" to represent the "long e" sound in Latin loanwords, as the element was named after the Latin word "caesius", meaning "sky blue".
Caesium is a chemical element with the symbol Cs and atomic number 55. It belongs to the alkali metal group and is characterized by being a highly reactive and soft silver-white metal. Its name is derived from "caesius," a Latin word that means "sky blue," which is the color of its emission spectrum.
In its natural state, caesium is not found in pure form but is instead usually obtained from the mineral pollucite. It has a low melting point and is one of the most electropositive elements, meaning it readily donates its outermost electron in chemical reactions. Caesium is highly reactive and reacts violently with water, igniting the hydrogen gas produced as a result.
Due to its reactivity, caesium finds various applications in research and technology. It is commonly used as a catalyst in various industrial chemical processes. Caesium-based compounds are also utilized in the production of specialty glasses and scintillation detectors, which are instruments used to measure radioactive materials. Additionally, caesium atomic clocks, which are highly accurate timekeeping devices, rely on the element's electronic properties.
However, caesium is highly toxic and requires caution when handling. Exposure to the element or its compounds can cause severe health risks. Consequently, the use and handling of caesium must be regulated and controlled.
Cesium.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "caesium" has its etymology from the Latin word "caesius", which means "sky blue". This reflects the characteristic blue spectral lines emitted by caesium when it is exposed to a flame. The element was discovered by Robert Bunsen and Gustav Kirchhoff in 1860, and they named it after the blue lines it produced during their spectroscopic analysis. It is worth noting that the spelling of "caesium" with the letter "a" instead of "e" (cesium) is the preferred IUPAC international spelling.