Magnesium carbide

Structural formula
${\displaystyle \mathrm {2\ Mg^{2+}\ [C{=}C{=}C]^{4-}} }$
General
Surname	Magnesium carbide
Molecular formula	Mg 2 C 3
Brief description	light to dark gray solid
External identifiers / databases
CAS number 12151-74-5 Wikidata Q1884281
properties
Molar mass	84.65 g mol −1
Physical state	firmly
Melting point	740-750 ° C (decomposition)
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 .

Magnesium carbide belongs in the group of carbides to the ionic carbides, which is formally derived from propyne (allylene) or propadiene (allene) and is therefore assigned to the group of allenides .

Extraction and presentation

The compound is formed during the pyrolysis of magnesium acetylide

${\displaystyle \mathrm {2\ MgC_{2}\rightarrow Mg_{2}C_{3}+C} }$

or by passing gaseous hydrocarbons (e.g. pentane ) over magnesium heated to 700 ° C.

properties

The crystal lattice of the light to dark gray compound contains isolated allylenide ions ([C = C = C] ⁴⁻ ). The hydrolysis of magnesium carbide produces propyne . Magnesium carbide breaks down into its elements at 740–750 ° C.

swell

1. ↑ ^{a b c d e} Georg Brauer (Ed.), With the collaboration of Marianne Baudler u. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume II, Ferdinand Enke, Stuttgart 1978, ISBN 3-432-87813-3 , p. 916.
2. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
3. ^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 , p. 1121.