Lithium cyanide
 | |
| Identifiers | |
|---|---|
| 2408-36-8 | |
| ChemSpider | 68007 |
| Jmol interactive 3D | Image |
| PubChem | 754-78 |
| UN number | 1935 |
| |
| Properties | |
| LiCN | |
| Molar mass | 32.959 g/mol |
| Appearance | White Powder |
| Density | 1.073 g/cm3 (18 °C) |
| Melting point | 160 °C (320 °F; 433 K) Dark colored |
| Boiling point | N/A |
| Soluble | |
| Henry's law constant (kH) |
N/A |
| Structure | |
| - | |
| Fourfold | |
| Hazards | |
| Safety data sheet | 742899 |
| EU classification (DSD) |
T+, Very Toxic N, Dangerous for the environment |
| R-phrases | 26/27/28-32-50/53 |
| S-phrases | 7-28-29-45-60-61 |
| NFPA 704 | |
| Flash point | 57 °C (135 °F; 330 K) |
| N/A | |
| Related compounds | |
| Related compounds |
Sodium cyanide, Potassium cyanide, Hydrogen Cyanide |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Lithium cyanide is an inorganic compound with the chemical formula LiCN. It is a white powder at room temperature. Lithium cyanide is commonly used as a reagent in inorganic/organometallic reactions. Lithium cyanide can be found in the environment from the reaction of lithium and acetonitrile, two compounds found in lithium sulfur oxide batteries. When the compound is exposed to the environment it can produce toxic fumes with weak acids found in nature.
Properties
Stability and reactivity
Lithium cyanide as a solid is stable under room temperature. LiCN, when melted at 160 °C, is highly hygroscopic. The compound decomposes to cyanamide and carbon when heated to a temperature close to but below 600°C. When acids, chlorates, and strong oxidizing agents react with LiCN, HCN is formed. HCN vapors are very toxic and reactive. If LiCN is heated in fire carbon dioxide CO2, nitrous oxides NOx, and lithium oxides will form.[4]
Reactions
Synthesis and production
- Li + R-CN → LiCN
- Li + HCN(Benzene) → LiCN
Lithium cyanide can be synthesized in high yields with liquid hydrogen cyanide and n-butyllithium. Other methods exist with the fundamental idea of adding the lithium cation to the cyanide anion.[4]
Cyanation
- RX + LiCN —THF→ RCN
Lithium cyanide is commonly used as a reagent in synthesizes of cyanide compounds, for example halide cyanides. The reagent offers advantages by allowing non-aqeous methods of cyanation.[5]
Environmental exposure
Lithium cyanide is an inorganic compound not commonly found in nature without human involvement. The most obtainable source of lithium is through lithium batteries. Specifically, lithium sulfur dioxide batteries can lead to the formation of lithium cyanide form the reaction between the two compounds found inside the battery, elemental lithium and acetonitrile. When lithium cyanide is introduced the environment, it can react with acids or strong oxidizing agents to produce toxic HCN vapors in the environment or produce carbon dioxide, nitrous oxides, and lithium oxides if introduced to fire. Concerns of the hazardousness of lithium sulfur oxide batteries waste were raised as lithium batteries become more obtainable. The US Environmental Protection Agency and Department of Defense evaluated the lithium sulfur oxide batteries and concluded that LiCN formation was one of the compounds leading to the hazardous waste.[6][7]
References
- ↑ J. A. Lely,, J. M. Bijvoet (1942), "The Crystal Structure of Lithium Cyanide", Recueil des Travaux Chimiques des Pays-Bas 61, London: WILEY-VCH Verlag
- ↑ Haynes, W.M (2013), "Bernard Lewis", in Bruno, Thomas., Handbook of Chemistry and Physics (93 ed.), Boca Raton, Florida: Fitzroy Dearborn
- ↑ Material Safety Data Sheet: Lithium Cyanide, 0.5M Solution in N,N-Dimethylformamide, Fisher Scientific, 16 June 1999
- 1 2 "Cyanides". E. I. du Pont de Nemours & Co., Inc. Retrieved 2012-11-02.
- ↑ "Non-aqueous cya nation of halides using lithium cyanide". Elsevier. Retrieved 2012-10-17.
- ↑ "Evaluation of Lithium Sulfur Dioxide Batteries" (PDF). U.S. Army Communications - Electronics Command and U.S. Army Electronics Research and Development Command. Retrieved 2012-10-23.
- ↑ "Regulatory status of spent and/or discarded lithium-sulfur dioxide (Li/S02) batteries". United States Environmental Protection Agency. 7 March 1984. Retrieved 2012-10-23.