Calcium Carbide

Title: Calcium Carbide
CAS Registry Number: 75-20-7
Additional Names: Acetylenogen
Molecular Formula: C2Ca
Molecular Weight: 64.10
Percent Composition: C 37.47%, Ca 62.52%
Line Formula: CaC2
Literature References: Prepn: Ehrlich in Handbook of Preparative Inorganic Chemistry Vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) p 943. Review: Brennan, J. Electrochem. Soc. 99, 61c (1952).
Properties: Grayish-black, irregular lumps or orthorhombic crystals; dec by water with evolution of acetylene leaving a residue of lime. d 2.22; mp 2300°.
Melting point: mp 2300°
Density: d 2.22
Use: Generating acetylene gas for lighting purposes (1 kg of carbide yields ~300 liters acetylene); as reducing agent, e.g., for direct reduction of copper sulfide to metallic copper; signal fires for marine service; manuf of calcium, iron, alloys, lampblack, cyanamide; welding and cutting metals.
Calcium Carbonate Calcium Chlorate Calcium Chloride Calcium Chromate(VI) Calcium Citrate

Calcium carbide
Calcium Carbide
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Identifiers
CAS number 75-20-7 YesY
PubChem 6352
ChemSpider 6112 YesY
Jmol-3D images Image 1
Properties
Molecular formula CaC2
Molar mass 64.099 g/mol
Appearance White powder to grey/black crystals
Density 2.22 g/cm3
Melting point 2,160 °C; 3,920 °F; 2,430 K
Boiling point 2,300 °C; 4,170 °F; 2,570 K
Solubility in water decomposes
Structure
Crystal structure Tetragonal [1]
Space group D174h, I4/mmm, tI6
Coordination
geometry
6
Thermochemistry
Std molar
entropy So298
70 J·mol−1·K−1
Std enthalpy of
formation ΔfHo298
−63 kJ·mol−1
Hazards
NFPA 704
NFPA 704.svg
3
3
2
W
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references
Calcium carbide.

Calcium carbide is a chemical compound with the chemical formula of CaC2. Its main use industrially is in the production of acetylene and calcium cyanamide.[2]

The pure material is colorless, however pieces of technical-grade calcium carbide are grey or brown and consist of about 80–85% of CaC2 (the rest is CaO (calcium oxide), Ca3P2 (calcium phosphide), CaS (calcium sulfide), Ca3N2 (calcium nitride), SiC (silicon carbide), etc.). Because of presence of PH3 (phosphine), NH3 (ammonia), and H2S (hydrogen sulfide), the smell of technical-grade calcium carbide is part of the process or production and is produced intentionally to be unpleasant in larger concentrations, and noticeable in smaller ones, as a part of warning system for unwanted leaks, fires or explosion.[citation needed]

It is illegally used for ripening fruits in India, consumption of which can lead to cancer.[3]