Difference between revisions of "Mercury(II) thiocyanate"
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| pKa = | | pKa = | ||
| pKb = | | pKb = | ||
| − | | Solubility = 0.069 g/100 | + | | Solubility = 0.069 g/100 ml (at 25 ºC) |
| SolubleOther = Soluble in dilute [[hydrochloric acid]], anhydrous [[ammonia]], KCN<br>Slightly soluble in [[ethanol]], [[diethyl ether]] | | SolubleOther = Soluble in dilute [[hydrochloric acid]], anhydrous [[ammonia]], KCN<br>Slightly soluble in [[ethanol]], [[diethyl ether]] | ||
| Solvent = | | Solvent = | ||
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| − | '''Mercury(II) thiocyanate''' is an inorganic chemical compound with the chemical formula '''Hg(SCN)<sub>2</sub>'''. When ignited, it will produce a large, expanding “snake”, effect known as the [[ | + | '''Mercury(II) thiocyanate''' is an inorganic chemical compound with the chemical formula '''Hg(SCN)<sub>2</sub>'''. When ignited, it will produce a large, expanding “snake”, effect known as the [[Pharaoh's serpent]]. |
==Properties== | ==Properties== | ||
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===Physical=== | ===Physical=== | ||
| − | Mercury(II) thiocyanate is a white solid, extremely poorly soluble in water, but somewhat soluble in other solvents and acids. It decomposes when heated above 165 °C. | + | Mercury(II) thiocyanate is a white solid, extremely poorly soluble in water, but somewhat soluble in other solvents and acids. It decomposes when heated above 165 °C. Its density at standard conditions is 3.71 g/cm<sup>3</sup>. |
==Availability== | ==Availability== | ||
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==Preparation== | ==Preparation== | ||
| − | Mercury(II) thiocyanate can be made by reacting a soluble thiocyanate salt, such as potassium thiocynate with mercury(II) nitrate: | + | Mercury(II) thiocyanate can be made by reacting a soluble thiocyanate salt, such as [[potassium thiocynate]] with [[mercury(II) nitrate]]: |
:Hg(NO<sub>3</sub>)<sub>2</sub> + 2 KSCN → Hg(SCN)<sub>2</sub> + 2 KNO<sub>3</sub> | :Hg(NO<sub>3</sub>)<sub>2</sub> + 2 KSCN → Hg(SCN)<sub>2</sub> + 2 KNO<sub>3</sub> | ||
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==Handling== | ==Handling== | ||
===Safety=== | ===Safety=== | ||
| − | Mercury(II) thiocyanate is very toxic and proper protection | + | Mercury(II) thiocyanate is very toxic and proper protection must be worn when handling the compound. |
===Storage=== | ===Storage=== | ||
Latest revision as of 12:13, 28 October 2017
| Names | |
|---|---|
| IUPAC name
Mercury(II) thiocyanate
| |
| Other names
Mercuric thiocyanate
Mercuric sulfocyanate | |
| Identifiers | |
| Jmol-3D images | Image |
| |
| Properties | |
| Hg(SCN)2 | |
| Molar mass | 316.755 g/mol |
| Appearance | White solid |
| Density | 3.71 g/cm3 |
| Melting point | 165 °C (329 °F; 438 K) (decomposes) |
| Boiling point | Decomposes |
| 0.069 g/100 ml (at 25 ºC) | |
| Solubility | Soluble in dilute hydrochloric acid, anhydrous ammonia, KCN Slightly soluble in ethanol, diethyl ether |
| Hazards | |
| Safety data sheet | ScienceLab |
| Flash point | 121 ºC |
| Lethal dose or concentration (LD, LC): | |
| LD50 (Median dose)
|
46 mg/kg (rat, oral) |
| Related compounds | |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Mercury(II) thiocyanate is an inorganic chemical compound with the chemical formula Hg(SCN)2. When ignited, it will produce a large, expanding “snake”, effect known as the Pharaoh's serpent.
Contents
Properties
Chemical
When ignited, mercury thiocyanate will decompose into an expanding residue, which has the form of a snake. The thermal decomposition is fairly complex and occurs in several stages:
- 2 Hg(SCN)2 → 2 HgS + CS2 + C3N4
- CS2 + 3O2 → CO2 + 2 SO2
- 2 C3N4 → 3 (CN)2 + N2
- HgS + O2 → Hg + SO2
Physical
Mercury(II) thiocyanate is a white solid, extremely poorly soluble in water, but somewhat soluble in other solvents and acids. It decomposes when heated above 165 °C. Its density at standard conditions is 3.71 g/cm3.
Availability
Mercury thiocyanate is sold by various chemical suppliers. It is sometimes sold on eBay.
Being a mercury compound, the sale of this compound is regulated in most countries.
Preparation
Mercury(II) thiocyanate can be made by reacting a soluble thiocyanate salt, such as potassium thiocynate with mercury(II) nitrate:
- Hg(NO3)2 + 2 KSCN → Hg(SCN)2 + 2 KNO3
Since Hg(SCN)2 is sparingly soluble in water, it will precipitate. Filter the precipitate and dry it, preferably in open air or in a desiccator. Avoid strong heat, as it cause it to decompose.
Projects
- Pharaoh’s serpent
Handling
Safety
Mercury(II) thiocyanate is very toxic and proper protection must be worn when handling the compound.
Storage
Mercury(II) thiocyanate should be kept in a closed bottle, away from corrosive vapors. DO NOT STORE IT IN ALUMINIUM CONTAINERS!
Disposal
Mercury(II) thiocyanate can be neutralized by turning it into mercury sulfide HgS, which is much less toxic. It then should be taken to special disposal centers.
References
Relevant Sciencemadness threads
- Chemical pages without CAS Registry Number
- Articles without EBI source
- Chemical pages without ChemSpiderID
- Chemical pages without DrugBank identifier
- Articles without KEGG source
- Articles without InChI source
- Articles without UNII source
- Articles containing unverified chemical infoboxes
- Chembox articles without image
- Chemical compounds
- Inorganic compounds
- Mercury compounds
- Thiocyanates
- Things that can kill you very quickly
- Things that should NOT be messed with except by professionals
- Solids
