Sodium hydrosulfide
| Sodium hydrosulfide | |
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Sodium hydrosulfide |
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Other names
Sodium bisulfide |
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| Identifiers | |
| CAS number | 16721-80-5  , 207683-19-0 (hydrate) |
| PubChem | 28015 |
| ChemSpider | 26058 |
| UNII | FWU2KQ177W |
| EC number | 240-778-0 |
| ChEMBL | CHEMBL1644699  |
| RTECS number | WE1900000 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | NaHS |
| Molar mass | 56.063 g/mol |
| Appearance | off-white solid, deliquescent |
| Density | 1.79 g/cm3 |
| Melting point |
52–54 ºC (hydrate) |
| Hazards | |
| MSDS | TDC MSDS |
| EU Index | Toxic |
| R-phrases | R17 R23 R24 R25 |
| Main hazards | Flammable solid, stench, releases hydrogen sulfide |
| NFPA 704 |
 2
3
0
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| Flash point | 90 ºC |
| Related compounds | |
| Other anions | Sodium hydroxide Sodium amide |
| Other cations | Ammonium hydrosulfide |
| Related compounds | Sodium sulfide |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Sodium hydrosulfide is the chemical compound with the formula NaHS. This compound is the product of the half neutralization of hydrogen sulfide with sodium hydroxide. NaHS is a useful reagent for the synthesis of organic and inorganic sulfur compounds. It is a colorless solid that typically smells like H2S due to hydrolysis by atmospheric moisture. In contrast with sodium sulfide, Na2S, which is insoluble in organic solvents, NaHS, being a 1:1 electrolyte, is more soluble. Alternatively, in place of NaHS, H2S can be treated with an organic amine to generate an ammonium salt. Solutions of HS− are sensitive to oxygen, converting mainly to polysulfides, indicated by the appearance of yellow.
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[edit] Structure and properties
Crystalline NaHS undergoes two phase transitions. At temperatures above 360 K, NaHS adopts the NaCl structure, which implies that the HS− behaves as a spherical anion due to its rapid rotation leading to equal occupancy of eight equivalent positions. Below 360 K, a rhombohedral structure forms, and the HS− sweeps out a discoidal shape. Below 114 K, the structure becomes monoclinic. The analogous rubidium and potassium compounds behave similarly.[1]
NaHS has a relatively low melting point of 350 °C. In addition to the aforementioned anhydrous forms, it can be obtained as two different hydrates, NaHS·2H2O and NaHS·3H2O. These three species are all colorless and behave similarly, but not identically.
[edit] Preparation
The usual laboratory synthesis entails treatment of sodium methoxide, NaOMe, with hydrogen sulfide:[2]
- NaOMe + H2S → NaHS + MeOH
Industrially, NaOH is employed as the base. The quality of the NaHS can be assayed by iodometric titration, exploiting the ability of HS– to reduce I2.
[edit] Applications
Thousands of tons of NaHS are produced annually. Its main uses are in paper manufacture as a makeup chemical for sulfur used in the Kraft process, as a flotation agent in copper mining where it is used to activate oxide mineral species, and in the leather industry for the removal of hair from hides.
[edit] References
- ^ Haarmann, F.; Jacobs, H.; Roessler, E.; Senker, J. (2002). "Dynamics of anions and cations in hydrogensulfides of alkali metals (NaHS, KHS, RbHS): A proton nuclear magnetic resonance study". J. Chem. Phys. 117 (3): 1269–1276. doi:10.1063/1.1483860.
- ^ Eibeck, R. I.; Zingaro, Ralph A.; McGlothlin, Raymond E. (1963). "Sodium Hydrogen Sulfide". Inorg. Synth.. Inorganic Syntheses 7: 128–31. doi:10.1002/9780470132388.ch35. ISBN 9780470132388
