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| Identifiers | |||
|---|---|---|---|
3D model (JSmol) | |||
| ChEBI | |||
| ChemSpider |
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| ECHA InfoCard | 100.015.614 | ||
| EC Number |
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| RTECS number |
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| UNII | |||
| UN number | 3077 | ||
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| Properties | |||
| [NH4][SCN] | |||
| Molar mass | 76.122 g/mol | ||
| Appearance | Colorlesshygroscopic crystalline solid | ||
| Density | 1.305 g/cm3 | ||
| Melting point | 149.5 °C (301.1 °F; 422.6 K) | ||
| Boiling point | 170 °C (338 °F; 443 K) (decomposes) | ||
| 128 g/(100 mL) (0 °C) | |||
| Solubility | soluble in liquidammonia,alcohol,acetone | ||
| −48.1·10−6 cm3/mol | |||
| Hazards | |||
| GHS labelling: | |||
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| Warning | |||
| H302,H312,H332,H410,H412 | |||
| P261,P264,P270,P271,P273,P280,P301+P312,P302+P352,P304+P312,P304+P340,P312,P322,P330,P363,P391,P501 | |||
| NFPA 704 (fire diamond) | |||
| Safety data sheet (SDS) | External MSDS | ||
| Related compounds | |||
Otheranions | Ammonium cyanate | ||
Othercations | |||
Related compounds | Ammonium cyanide | ||
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |||
Ammonium thiocyanate is aninorganic compound with the formula[NH4]+[SCN]−. It is anammoniumsalt ofthiocyanic acid. It consists of ammoniumcations[NH4]+ andthiocyanateanions[SCN]−.
Ammonium thiocyanate is used in the manufacture ofherbicides,thiourea, and transparent artificialresins; inmatches; as a stabilizing agent in photography; in various rustproofing compositions; as an adjuvant in textile dyeing and printing; as a tracer in oil fields; in the separation ofhafnium fromzirconium (important for the production of hafnium-freezircalloy for use in nuclearfuel cladding), and intitrimetric analyses.
In May 1945,USAAFGeneral Victor E. Betrandias advanced a proposal to his superior GeneralArnold to use of ammonium thiocyanate to reducerice crops inJapan as part of thebombing raids on their country.[1]
Ammonium thiocyanate can also be used to determine the iron content in soft drinks by colorimetry.
Ammonium thiocyanate may also be used to separate quinidine, from liquors, after the isolation of quinine from the neutral, aqueous, sulphate solution. The salt is added to the hot solution and the gummy solid that forms is strained off from the liquid. The solid is then refluxed with methanol, which dissolves most of the impurities, leaving the quinidine thiocyanate as a crystalline solid of 90 - 95% purity. Following separation, (usually by centrifuge) the solid may then be further purified to pharmaceutical quality. (Quinidine is used for the treatment of heart arrhythmia and therefore has considerable value.)
Ammonium thiocyanate is made by the reaction ofcarbon disulfide with aqueousammonia.Ammonium dithiocarbamate is formed as an intermediate in this reaction, which upon heating, decomposes to ammonium thiocyanate andhydrogen sulfide:
CS2 + 2 NH3(aq) → [NH2−CS2]−[NH4]+ → [NH4]+[SCN]− + H2S
Ammonium thiocyanate is stable in air; however, upon heating itisomerizes tothiourea:
The equilibrium mixtures at 150 °C and 180 °C contain 30.3% and 25.3% (by weight) thiourea, respectively. When heated at 200 °C, the dry powder decomposes to ammonia, hydrogen sulfide, andcarbon disulfide, leaving a residue ofguanidinium thiocyanate.
[NH4]+[SCN]− is weakly acidic due to the ammonium ion; it reacts with alkali hydroxides, such assodium hydroxide orpotassium hydroxide to formsodium thiocyanate orpotassium thiocyanate, along with water and ammonia. The thiocyanate anion, specifically, reacts with ferric salts to form a deep-red ferric thiocyanate derivative (of unknown structure).[2]
