Sodium hydrosulfide


Sodium hydrosulfide is the chemical compound with the formula NaSH. This compound is the product of the half-neutralization of hydrogen sulfide (H2S) with sodium hydroxide. NaSH and sodium sulfide are used industrially, often for similar purposes. Solid NaSH is colorless. The solid has an odor of H2S owing to hydrolysis by atmospheric moisture. In contrast with sodium sulfide (Na2S), which is insoluble in organic solvents, NaSH, being a 1:1 electrolyte, is more soluble.

Sodium hydrosulfide
IUPAC name
Sodium hydrosulfide
Other names
Sodium bisulfide
Sodium sulfhydrate
Sodium hydrogen sulfide
  • 16721-80-5 checkY
  • 207683-19-0 (hydrate) ☒N
3D model (JSmol)
  • Interactive image
  • ChEMBL1644699 ☒N
  • 26058 checkY
ECHA InfoCard 100.037.056 Edit this at Wikidata
EC Number
  • 240-778-0
  • 6278
  • 28015
RTECS number
  • WE1900000
  • FWU2KQ177W checkY
UN number 2922 2318
  • DTXSID3029738 Edit this at Wikidata
  • InChI=1S/Na.H2S/h;1H2/q+1;/p-1 checkY
  • InChI=1/Na.H2S/h;1H2/q+1;/p-1
  • [Na+].[SH-]
Molar mass 56.063 g/mol
Appearance off-white solid, deliquescent
Density 1.79 g/cm3
Melting point 350.1 °C (662.2 °F; 623.2 K) (anhydrous)
55 °C (dihydrate)
22 °C (trihydrate)
50 g/100 mL (22 °C)
Solubility soluble in alcohol, ether
Occupational safety and health (OHS/OSH):
Main hazards
Flammable solid, stench, releases hydrogen sulfide
GHS labelling:
GHS02: FlammableGHS05: CorrosiveGHS06: ToxicGHS09: Environmental hazard
H226, H251, H290, H301, H314, H400
P210, P233, P234, P235+P410, P240, P241, P242, P243, P260, P264, P270, P273, P280, P301+P310, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P330, P363, P370+P378, P390, P391, P403+P235, P404, P405, P407, P413, P420, P501
NFPA 704 (fire diamond)
Flash point 90 °C (194 °F; 363 K)
Safety data sheet (SDS) TDC MSDS
Related compounds
Other anions
Sodium hydroxide
Sodium amide
Other cations
Ammonium hydrosulfide
Related compounds
Sodium sulfide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Structure and propertiesEdit

Crystalline NaHS undergoes two phase transitions. At temperatures above 360 K, NaSH adopts the NaCl structure, which implies that the HS behaves as a spherical anion owing 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]

NaSH has a relatively low melting point of 350 °C. In addition to the aforementioned anhydrous forms, it can be obtained as two different hydrates, NaSH·2H2O and NaSH·3H2O. These three species are all colorless and behave similarly, but not identically. It can be used to precipitate other metal hydrosulfides, by treatment of aqueous solutions of their salts with sodium hydrosulfide. It is analogous to sodium hydroxide, and is a strong base.


One laboratory synthesis entails treatment of sodium ethoxide (NaOEt) with hydrogen sulfide:[2]


An alternative method involves reaction of sodium with hydrogen sulfide.[3]


Thousands of tons of NaSH are produced annually. Its main uses are in cloth and 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.[4]


  1. ^ 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. Bibcode:2002JChPh.117.1269H. doi:10.1063/1.1483860.
  2. ^ Eibeck, R. I. (1963). "Sodium Hydrogen Sulfide". Inorganic Syntheses. 7: 128–31. doi:10.1002/9780470132388.ch35. ISBN 9780470132388.
  3. ^ Pavlik, Jeffrey W.; Noll, Bruce C.; Oliver, Allen G.; Schulz, Charles E.; Scheidt, W. Robert (2010). "Hydrosulfide (HS) Coordination in Iron Porphyrinates". Inorganic Chemistry. 49 (3): 1017–1026. doi:10.1021/ic901853p. PMC 2811220. PMID 20038134.
  4. ^ Butts, David; Bush, David R.; Updated By Staff (2013). "Sodium Sulfates and Sulfides". Kirk-Othmer Encyclopedia of Chemical Technology. doi:10.1002/0471238961.1915040902212020.a01.pub3. ISBN 978-0471238966.