Lithium hydroxide

Lithium hydroxide
IUPAC name

Lithium hydroxide
Other names

Lithine
Identifiers
CAS number 1310-65-2 Y, 
1310-66-3 (monohydrate)
PubChem 3939
ChemSpider 3802 Y
UNII 903YL31JAS Y
UN number 2680
ChEBI CHEBI:33979 Y
RTECS number OJ6307070
Jmol-3D images Image 1
Properties
Molecular formula LiOH
Molar mass 23.95 g/mol
Appearance hygroscopic white solid
odorless
Density 1.46 g/cm3 (anhydrous)
1.51 g/cm3 (monohydrate)
Melting point

462 °C
Boiling point

924 °C decomp.
Solubility in water anhydrous:
12.8 g/100 mL (20 °C)
12.5 g/100 mL (25 °C)
17.5 g/100 mL (100 °C)
monohydrate:
22.3 g/100 mL (10 °C)
26.8 g/100 mL (100 °C)[1]
Refractive index (nD) 1.464 (anhydrous)
1.460 (monohydrate)
Thermochemistry
Std enthalpy of
formation ΔfHo298		 -20.36 kJ/g
Specific heat capacity, C 2.071 J/g K
Hazards
MSDS ICSC 0913
ICSC 0914 (monohydrate)
EU Index Not listed
Main hazards Corrosive
NFPA 704
0
3
0
Flash point Non-flammable
Related compounds
Other anions Lithium amide
Other cations Sodium hydroxide
Potassium hydroxide
Rubidium hydroxide
Caesium hydroxide
Related compounds Lithium oxide
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Lithium hydroxide is an inorganic compound with the formula LiOH. It is a white hygroscopic crystalline material. It is soluble in water and slightly soluble in ethanol. It is available commercially in anhydrous form and as the monohydrate (LiOH.H2O), both of which are strong bases.

Contents

Production and reactions

Lithium hydroxide is produced in a metathesis reaction between lithium carbonate and calcium hydroxide:[2]

Li2CO3 + Ca(OH)2 → 2 LiOH + CaCO3

The initially produced hydrate is dehydrated by heating under vacuum up to 180 °C.

In the laboratory, lithium hydroxide arises by the action of water on lithium or lithium oxide. The equations for these processes follow:

2 Li + 2 H2O → 2 LiOH + H2
Li2O + H2O → 2 LiOH

Typically, these reactions are avoided.

Although lithium carbonate is more widely used, the hydroxide is an effective precursor to lithium salts, e.g.

LiOH + HF → LiF + H2O.

Applications

Lithium hydroxide is mainly consumed for the production of lithium greases. A popular lithium grease is lithium stearate, which is a general-purpose lubricating grease due to its high resistance to water and usefulness at both high and low temperatures.

Carbon dioxide scrubbing

Further information: carbon dioxide scrubber

Lithium hydroxide is used in breathing gas purification systems for spacecraft (Lithium hydroxide canisters in the Lunar Module and Command/Service Module (after modification) were lifelines for the Apollo 13 astronauts), submarines, and rebreathers to remove carbon dioxide from exhaled gas by producing lithium carbonate and water:[3]

2 LiOH·H2O + CO2 → Li2CO3 + 3 H2O

Or,

2LiOH + CO2 → Li2CO3 + H2O

The latter, anhydrous hydroxide, is preferred for its lower mass and lesser water production for respirator systems in spacecraft. One gram of anhydrous lithium hydroxide can remove 450 cm3 of carbon dioxide gas. The monohydrate loses its water at 100–110 °C.

Other uses

It is used as a heat transfer medium and as a storage-battery electrolyte. It is also used in ceramics and some Portland cement formulations. Lithium hydroxide (isotopically enriched in lithium-7) is used to alkalize the reactor coolant in pressurized water reactors for corrosion control.

See also

References

  1. ^ Lide, David R., ed (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3. 
  2. ^ Wietelmann, U; Bauer, RJ (2000). "Lithium and Lithium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a15_393. ISBN 3527306730. 
  3. ^ Jaunsen, JR (1989). "The Behavior and Capabilities of Lithium Hydroxide Carbon Dioxide Scrubbers in a Deep Sea Environment". US Naval Academy Technical Report. USNA-TSPR-157. http://archive.rubicon-foundation.org/4998. Retrieved 2008-06-17. 

External links