| IUPAC names
| Other names
|Molar mass||59.07 g/mol|
|Appearance||Hygroscopic colorless solid|
|Melting point||50 °C (122 °F; 323 K)|
|0.184 g/100 ml (20 °C)|
|Solubility||Soluble in polar solvents|
|Vapor pressure||2.2 mmHg at 25 °C|
Std enthalpy of
|−57 – −55 kJ/mol|
|Safety data sheet||Fluorochem|
|Lethal dose or concentration (LD, LC):|
LD50 (Median dose)
|475 mg/kg (rat, oral)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Guanidine is an organic compound, a base with the formula HNC(NH2)2. Guanidine is sometimes shortened to Gdn.
As a base, guanidine will react with acids to form salts. By protanating guanidine, the guanidinium ion is formed.
- HNC(NH2)2 + HCl → C(NH2)3+Cl-
Guanidine is a solid white hygroscopic compound, slightly soluble in water.
Guanidinium salts, of the other hand, can be purchased from many chemical suppliers. To obtain the free base, simply react the salt with a stronger base then extract the resulting guanidine.
Free base guanidine can be prepared from guanidine by adding sodium hydroxide to a guanidinium salt, then recrystallized from the solvent.
For the preparation of guanidinium salts, check the page for each compound.
Guanidine can also be obtained from oxidative degradation of guanine, isolated from Peruvian guano (hence its name). Guano fertilizer can be bought from hardware and gardening stores.
- Make rocket fuel
- Make guanidinium salts (guanidinium carbonate, guanidinium chloride, guanidinium nitrate, guanidinium perchlorate, guanidinium sulfate)
Guanidine and its salts aren't volatile or very toxic and don't require special handling.
Guanidine free base should be kept in closed bottles, in a dry place.
No special disposal is required. Some guanidinium salts are even used as fertilizer.