Caesium hydride or cesium hydride (CsH) is a compound of

caesium Caesium (IUPAC spelling) (or cesium in American English) is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of , which makes it one of only five elemental metals that a ...

and

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...

. It is an

alkali metal hydride In chemistry, a hydride is formally the anion of hydrogen( H−). The term is applied loosely. At one extreme, all compounds containing covalently bound H atoms are called hydrides: water (H2O) is a hydride of oxygen, ammonia is a hydride of ...

. It was the first substance to be created by light-induced particle formation in metal vapor, and showed promise in early studies of an

ion propulsion An ion thruster, ion drive, or ion engine is a form of electric propulsion used for spacecraft propulsion. It creates thrust by accelerating ions using electricity. An ion thruster ionizes a neutral gas by extracting some electrons out of a ...

system using caesium. It is the most reactive stable

alkaline metal The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K),The symbols Na and K for sodium and potassium are derived from their Latin names, ''natrium'' and ''kalium''; these are still the origins of the names ...

hydride of all. It is a powerful

superbase A superbase is a compound that has a particularly high affinity for protons. Superbases are of theoretical interest and potentially valuable in organic synthesis. Superbases have been described and used since the 1850s.''Superbases for Organic ...

and reacts with water extremely vigorously. The caesium nuclei in CsH can be hyperpolarized through interactions with an optically pumped caesium vapor in a process known as

spin-exchange optical pumping In quantum mechanics, spin-exchange is an interaction process between two particles mediated by an exchange interaction. It preserves total angular momentum of the system but may allow other aspects of the system to change. When two spin-polarized ...

(SEOP). SEOP can increase the

nuclear magnetic resonance Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are perturbed by a weak oscillating magnetic field (in the near field) and respond by producing an electromagnetic signal with a ...

(NMR) signal of caesium nuclei by an order of magnitude. It is very difficult to make caesium hydride in a pure form. Caesium hydride can be produced by heating caesium carbonate and metallic magnesium in hydrogen at 580 to 620 degrees

Celsius The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The ...

Crystal structure

At room temperature and atmospheric pressure, CsH has the same structure as

NaCl Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...

References

Caesium compounds Metal hydrides Superbases Rock salt crystal structure {{inorganic-compound-stub