| Names | |
|---|---|
Other names
| |
| Identifiers | |
3D model (JSmol) | |
| |
| |
| Properties | |
| Mg(CN)2 | |
| Molar mass | 76.34 g/mol |
| Appearance | White solid |
| Melting point | 500 °C (932 °F; 773 K) (decomposes) |
| Reacts to formmagnesium hydroxide | |
| Solubility in ammonia | Slightly soluble |
| Related compounds | |
Otheranions | Magnesium thiocyanate |
Othercations | Calcium cyanide |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Magnesium cyanide is a chemical compound with the formula Mg(CN)2. It is a toxic white solid. Unlikecalcium isocyanide, the cyanide ligands prefer to coordinate at carbon, with a 0.3‑kcal/mol isomerization barrier.[1] When this salt is heated to 500 °C, it decomposes tomagnesium nitride.[2]
The first attempt to prepare magnesium cyanide was attempted in 1924. It was attempted by reacting a solution ofhydrogen cyanide in water with magnesium metal:[2]
However, no magnesium cyanide was observed, onlymagnesium hydroxide formed. To avoid this problem, instead of using water as the reaction medium, pureammonia was used at -30 °C. This formed magnesium cyanide ammoniate, which in turn was heated to 180 °C to produce magnesium cyanide.[3]Other methods are possible, such as the decomposition ofmagnesium ferricyanide in an electric carbon tube, which producesiron carbide as a byproduct.[2]
Magnesium cyanide reacts withsilver nitrate to form magnesium silver cyanide, with the formula MgAg2(CN)4. When this compound is heated it produceshydrogen cyanide gas and magnesium hydroxide in the presence of water, which meant it could not be used as a pathway for the production of magnesium cyanide. When silver nitrate reacts with magnesium cyanide, it also produces another magnesium silver cyanide, with the formula MgAg(CN)3.[2]
Magnesium cyanide, like all cyanides, is extremely toxic. When it enters the body, it inhibits tissue respiration enzymes, and tissues lose the ability to absorb oxygen from the blood.[4]