Lithium carbide

Structural formula
General
Surname	Lithium carbide
other names	Lithium acetylide Dilithium acetylide Lithium ethinediide
Molecular formula	Li 2 C 2
Brief description	translucent, white to gray crystalline solid
External identifiers / databases
CAS number 1070-75-3 EC number 213-980-1 ECHA InfoCard 100.012.710 PubChem 66115 ChemSpider 59503 Wikidata Q421181
properties
Molar mass	37.90 g mol −1
Physical state	firmly
density	1.3 g cm −3
Melting point	decomposition
solubility	almost insoluble in organic solvents
safety instructions
GHS hazard labeling no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Lithium carbide is a chemical compound from the group of carbides .

Extraction and presentation

Lithium carbide can be obtained by reacting lithium with carbon .

${\displaystyle \mathrm {2\ Li+2\ C\longrightarrow Li_{2}C_{2}} }$

At higher pressures, LiC ₂ or LiC ₄ is formed instead of lithium carbide (Li ₂ C ₂ ) .

If lithium carbonate is heated in an electric furnace with an excess of carbon , lithium carbide is also formed.

${\displaystyle \mathrm {Li_{2}CO_{3}+4\ C\longrightarrow Li_{2}C_{2}+3\ CO} }$

In diethyl ether , lithium carbide can be produced by the reaction of 1,2-dichloroethane with phenyllithium , producing a thick, colorless precipitate of lithium carbide and monolithium acetylide.

properties

Physical Properties

Lithium carbide is a crystalline solid that has an orthorhombic crystal system with the space group Immm (space group no. 71) and the lattice parameters a = 365.5  pm , b = 544.0 pm and c = 483.3 pm. It is isotypic to rubidium peroxide (Rb ₂ O ₂ ) and cesium peroxide (Cs ₂ O ₂ ).

The standard enthalpy of formation is −59.5 kJ / mol.

Chemical properties

Lithium carbide reacts with water to form ethyne .

${\displaystyle \mathrm {Li_{2}C_{2}+2\ H_{2}O\ \longrightarrow \ 2\ LiOH+C_{2}H_{2}\uparrow } }$

Lithium carbide also decomposes in molten potassium hydroxide , although it is only slowly attacked by concentrated acids.

Individual evidence

1. ^ ^{A b} R. Abegg, F. Auerbach, I. Koppel: "Handbuch der inorganic Chemie", Verlag S. Hirzel, 1908, 2nd volume, 1st part, p. 146ff. Full text
2. ↑ ^{a b c d e f} Jean D'Ans, Ellen Lax: Paperback for chemists and physicists: Volume 3 . Springer, 2007, ISBN 978-3-540-60035-0 ( page 532 in the Google book search).
3. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. CRC Press, 2009, ISBN 978-1-4200-9084-0 .
4. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
5. ^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 , p. 1150.
6. ↑ M. Zafar, A. Munshi: Handbook of solid state batteries & capacitors . 1995, ISBN 978-981-02-1794-5 ( page 430 in the Google book search).
7. ^ Georg Wittig, Günther Harborth: About the behavior of non-aromatic halides and ethers towards phenyllithium . In: Reports of the German Chemical Society . 77, No. 5, July 1944, pp. 306-314. doi : 10.1002 / cber.19440770505 .
8. ↑ Robert Juza , Volker Wehle: Crystal structure of lithium carbide. In: The natural sciences. 52, 1965, pp. 537-537, doi : 10.1007 / BF00645818 .