Sodium sulfide

Sodium sulfide
Names
	Other names Disodium sulfide
Identifiers
CAS Number	1313-82-2 ; 1313-83-3 (pentahydrate) ; 1313-84-4 (nonahydrate) ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:76208 ;
ChemSpider	14120 ;
ECHA InfoCard	100.013.829
EC Number	215-211-5;
PubChem CID	237873;
RTECS number	WE1905000;
UNII	YGR27ZW0Y7 ; 6U55N59SZ2 (pentahydrate) ; C02T02993U (nonahydrate) ;
UN number	1385 (anhydrous); 1849 (hydrate)
CompTox Dashboard (EPA)	DTXSID0029636 ;
	InChI InChI=1S/2Na.S/q2+1;-2 Key: GRVFOGOEDUUMBP-UHFFFAOYSA-N ; InChI=1/2Na.S/q2+1;-2 Key: GRVFOGOEDUUMBP-UHFFFAOYAP;
	SMILES [Na+].[Na+].[S-2];
Properties
Chemical formula	Na2S
Molar mass	78.0452 g/mol (anhydrous); 240.18 g/mol (nonahydrate)
Appearance	colorless, hygroscopic solid
Odor	none
Density	1.856 g/cm3 (anhydrous) ; 1.58 g/cm3 (pentahydrate) ; 1.43 g/cm3 (nonohydrate)
Melting point	1,176 °C (2,149 °F; 1,449 K) (anhydrous) ; 100 °C (pentahydrate) ; 50 °C (nonahydrate)
Solubility in water	12.4 g/100 mL (0 °C) ; 18.6 g/100 mL (20 °C) ; 39 g/100 mL (50 °C) ; (hydrolyses)
Solubility	insoluble in ether ; slightly soluble in alcohol
Magnetic susceptibility (χ)	−39.0·10−6 cm3/mol
Structure
Crystal structure	Antifluorite (cubic), cF12
Space group	Fm3m, No. 225
Coordination geometry	Tetrahedral (Na+); cubic (S2−)
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H311, H314, H400
Precautionary statements	P260, P264, P270, P273, P280, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P322, P330, P361, P363, P391, P405, P501
NFPA 704 (fire diamond)	3 1 1
Autoignition; temperature	> 480 °C (896 °F; 753 K)
Safety data sheet (SDS)	ICSC 1047
Related compounds
Other anions	Sodium oxide; Sodium selenide; Sodium telluride; Sodium polonide
Other cations	Lithium sulfide; Potassium sulfide; Rubidium sulfide; Caesium sulfide
Related compounds	Sodium hydrosulfide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Sodium sulfide is a chemical compound with the formula Na₂S, or more commonly its hydrate Na₂S·9H₂O. Both the anhydrous and the hydrated salts in pure crystalline form are colorless solids, although technical grades of sodium sulfide are generally yellow to brick red owing to the presence of polysulfides and commonly supplied as a crystalline mass, in flake form, or as a fused solid. They are water-soluble, giving strongly alkaline solutions. When exposed to moisture, Na₂S immediately hydrates to give sodium hydrosulfide.

Some commercial samples are specified as Na₂S·xH₂O, where a weight percentage of Na₂S is specified. Commonly available grades have around 60% Na₂S by weight, which means that x is around 3. These grades of sodium sulfide are often marketed as 'sodium sulfide flakes'. These samples consist of NaSH, NaOH, and water.

Structure

The structures of sodium sulfides have been determined by X-ray crystallography. The nonahydrate features S2- hydrogen-bonded to 12 water molecules.^[2] The pentahydrate consists of S^2- centers bound to Na⁺ and encased by an array of hydrogen bonds.^[3] Anhydrous Na₂S, which is rarely encountered, adopts the antifluorite structure,^[4]^[5] which means that the Na⁺ centers occupy sites of the fluoride in the CaF₂ framework, and the larger S²⁻ occupy the sites for Ca²⁺.

Production

Industrially Na₂S is produced by carbothermic reduction of sodium sulfate often using coal:^[6]

Na₂SO₄ + 2 C → Na₂S + 2 CO₂

In the laboratory, the salt can be prepared by reduction of sulfur with sodium in anhydrous ammonia, or by sodium in dry THF with a catalytic amount of naphthalene (forming sodium naphthalenide):^[7]

2 Na + S → Na₂S

Reactions with inorganic reagents

The sulfide ion in sulfide salts such as sodium sulfide can incorporate a proton into the salt by protonation:

S²⁻
+ H⁺ → SH⁻

Because of this capture of the proton ( H⁺), sodium sulfide has basic character. Sodium sulfide is strongly basic, able to absorb two protons. Its conjugate acid is sodium hydrosulfide (SH⁻
). An aqueous solution contains a significant portion of sulfide ions that are singly protonated.

S²⁻
+ H₂O

{\ce {<=>>}}

SH⁻
+ OH⁻

SH⁻
+ H₂O

{\ce {<<=>}}

H₂S + OH⁻

Sodium sulfide is unstable in the presence of water due to the gradual loss of hydrogen sulfide into the atmosphere.

When heated with oxygen and carbon dioxide, sodium sulfide can oxidize to sodium carbonate and sulfur dioxide:

2 Na₂S + 3 O₂ + 2 CO₂ → 2 Na₂CO₃ + 2 SO₂

Oxidation with hydrogen peroxide gives sodium sulfate:^[8]

Na₂S + 4 H₂O₂ → 4 H₂O + Na₂SO₄

Upon treatment with sulfur, sodium polysulfides are formed:

2 Na₂S + S₈ → 2 Na₂S₅

Pulp and paper industry

In terms of its dominant use, "sodium sulfide" is primarily used in the kraft process in the pulp and paper industry. It aids in the delignification process, affording cellulose, which is the main component of paper.

It is used in water treatment as an oxygen scavenger agent and also as a metals precipitant; in chemical photography for toning black and white photographs; in the textile industry as a bleaching agent, for desulfurising and as a dechlorinating agent; and in the leather trade for the sulfitisation of tanning extracts. It is used in chemical manufacturing as a sulfonation and sulfomethylation agent. It is used in the production of rubber chemicals, sulfur dyes and other chemical compounds. It is used in other applications including ore flotation, oil recovery, making dyes, and detergent. It is also used during leather processing, as an unhairing agent in the liming operation.

Reagent in organic chemistry

Installation of carbon-sulfur bonds

Alkylation of sodium sulfide give thioethers:

Na₂S + 2 RX → R₂S + 2 NaX

Even aryl halides participate in this reaction.^[9] By a broadly similar process sodium sulfide can react with alkenes in the thiol-ene reaction to give thioethers. Sodium sulfide can be used as nucleophile in Sandmeyer type reactions.^[10]

Reducing agent

Aqueous solution of sodium sulfide will reduce nitro groups to amine. This conversion is applied to production of some azo dyes since other reducible groups, e.g. azo group, remain intact.^[11] The reduction of nitro aromatic compounds to amines using sodium sulfide is known as the Zinin reaction in honor of its discoverer.^[12] Hydrated sodium sulfide reduces 1,3-dinitrobenzene derivatives to the 3-nitroanilines.^[13]

Other reactions

Sulfide has also been employed in photocatalytic applications.^[14]

Safety

Consisting of the equivalent of sodium hydroxide, sodium sulfide is strongly alkaline and can cause chemical burns. It reacts rapidly with acids to produce hydrogen sulfide, which is highly toxic.

References

^ Kurzin, Alexander V.; Evdokimov, Andrey N.; Golikova, Valerija S.; Pavlova, Olesja S. (June 9, 2010). "Solubility of Sodium Sulfide in Alcohols". J. Chem. Eng. Data. 55 (9): 4080–4081. doi:10.1021/je100276c.
^ Preisinger, A.; Mereiter, K.; Baumgartner, O.; Heger, G.; Mikenda, W.; Steidl, H. (1982). "Hydrogen Bonds in Na₂S·9D₂O: Neutron Diffraction, X-Ray Diffraction and Vibrational Spectroscopic Studies". Inorganica Chimica Acta. 57: 237–246. doi:10.1016/S0020-1693(00)86975-3.
^ Mereiter, Kurt; Preisinger, Anton; Zellner, Andrea; Mikenda, Werner; Steidl, Heinz (1984). "Hydrogen Bonds in Na₂S·5H₂O: X-ray Diffraction and Vibrational Spectroscopic Study". J. Chem. Soc., Dalton Trans. (7): 1275–1277. doi:10.1039/dt9840001275.
^ Zintl, E; Harder, A; Dauth, B. (1934). "Gitterstruktur der oxyde, sulfide, selenide und telluride des lithiums, natriums und kaliums". Z. Elektrochem. Angew. Phys. Chem. 40: 588–93.
^ Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
^ Holleman, A.F.; Wiberg, E. (2001). Inorganic Chemistry. San Diego: Academic Press. ISBN 0-12-352651-5..
^ So, J.-H; Boudjouk, P; Hong, Harry H.; Weber, William P. (2007). "Hexamethyldisilathiane". Inorg. Synth. 29: 30–32. doi:10.1002/9780470132609.ch11. ISBN 978-0-470-13260-9.
^ L. Lange, W. Triebel, "Sulfides, Polysulfides, and Sulfanes" in Ullmann's Encyclopedia of Industrial Chemistry 2000, Wiley-VCH, Weinheim. doi:10.1002/14356007.a25_443
^ Charles C. Price, Gardner W. Stacy "p-Aminophenyldisulfide" Org. Synth. 1948, vol. 28, 14. doi:10.15227/orgsyn.028.0014
^ Khazaei; et al. (2012). "synthesis of thiophenols". Synthesis Letters. 23 (13): 1893–1896. doi:10.1055/s-0032-1316557. S2CID 196805424.
^ Yu; et al. (2006). "Syntheses of functionalized azobenzenes". Tetrahedron. 62 (44): 10303–10310. doi:10.1016/j.tet.2006.08.069.
^ Zinin, N. (1842). "Beschreibung einiger neuer organischer Basen, dargestellt durch die Einwirkung des Schwefelwasserstoffes auf Verbindungen der Kohlenwasserstoffe mit Untersalpetersäure" [Description of some new organic bases, represented by the action of hydrogen sulphide on hydrocarbons with sub-nitric acid]. Journal für Praktische Chemie (in German). 27 (1): 140–153. doi:10.1002/prac.18420270125.
^ Hartman, W. W.; Silloway, H. L. (1945). "2-Amino-4-nitrophenol". Organic Syntheses. 25: 5. doi:10.15227/orgsyn.025.0005{{cite journal}}: CS1 maint: multiple names: authors list (link).
^ Savateev, A.; Dontsova, D.; Kurpil, B.; Antonietti, M. (June 2017). "Highly crystalline poly(heptazine imides) by mechanochemical synthesis for photooxidation of various organic substrates using an intriguing electron acceptor – Elemental sulfur". Journal of Catalysis. 350: 203–211. doi:10.1016/j.jcat.2017.02.029.

[1] Kurzin, Alexander V.; Evdokimov, Andrey N.; Golikova, Valerija S.; Pavlova, Olesja S. (June 9, 2010). "Solubility of Sodium Sulfide in Alcohols". J. Chem. Eng. Data. 55 (9): 4080–4081. doi:10.1021/je100276c.

[2] Preisinger, A.; Mereiter, K.; Baumgartner, O.; Heger, G.; Mikenda, W.; Steidl, H. (1982). "Hydrogen Bonds in Na₂S·9D₂O: Neutron Diffraction, X-Ray Diffraction and Vibrational Spectroscopic Studies". Inorganica Chimica Acta. 57: 237–246. doi:10.1016/S0020-1693(00)86975-3.

[3] Mereiter, Kurt; Preisinger, Anton; Zellner, Andrea; Mikenda, Werner; Steidl, Heinz (1984). "Hydrogen Bonds in Na₂S·5H₂O: X-ray Diffraction and Vibrational Spectroscopic Study". J. Chem. Soc., Dalton Trans. (7): 1275–1277. doi:10.1039/dt9840001275.

[4] Zintl, E; Harder, A; Dauth, B. (1934). "Gitterstruktur der oxyde, sulfide, selenide und telluride des lithiums, natriums und kaliums". Z. Elektrochem. Angew. Phys. Chem. 40: 588–93.

[5] Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.

[6] Holleman, A.F.; Wiberg, E. (2001). Inorganic Chemistry. San Diego: Academic Press. ISBN 0-12-352651-5..

[7] So, J.-H; Boudjouk, P; Hong, Harry H.; Weber, William P. (2007). "Hexamethyldisilathiane". Inorg. Synth. 29: 30–32. doi:10.1002/9780470132609.ch11. ISBN 978-0-470-13260-9.

[8] L. Lange, W. Triebel, "Sulfides, Polysulfides, and Sulfanes" in Ullmann's Encyclopedia of Industrial Chemistry 2000, Wiley-VCH, Weinheim. doi:10.1002/14356007.a25_443

[9] Charles C. Price, Gardner W. Stacy "p-Aminophenyldisulfide" Org. Synth. 1948, vol. 28, 14. doi:10.15227/orgsyn.028.0014

[10] Khazaei; et al. (2012). "synthesis of thiophenols". Synthesis Letters. 23 (13): 1893–1896. doi:10.1055/s-0032-1316557. S2CID 196805424.

[11] Yu; et al. (2006). "Syntheses of functionalized azobenzenes". Tetrahedron. 62 (44): 10303–10310. doi:10.1016/j.tet.2006.08.069.

[12] Zinin, N. (1842). "Beschreibung einiger neuer organischer Basen, dargestellt durch die Einwirkung des Schwefelwasserstoffes auf Verbindungen der Kohlenwasserstoffe mit Untersalpetersäure" [Description of some new organic bases, represented by the action of hydrogen sulphide on hydrocarbons with sub-nitric acid]. Journal für Praktische Chemie (in German). 27 (1): 140–153. doi:10.1002/prac.18420270125.

[13] Hartman, W. W.; Silloway, H. L. (1945). "2-Amino-4-nitrophenol". Organic Syntheses. 25: 5. doi:10.15227/orgsyn.025.0005{{cite journal}}: CS1 maint: multiple names: authors list (link).

[14] Savateev, A.; Dontsova, D.; Kurpil, B.; Antonietti, M. (June 2017). "Highly crystalline poly(heptazine imides) by mechanochemical synthesis for photooxidation of various organic substrates using an intriguing electron acceptor – Elemental sulfur". Journal of Catalysis. 350: 203–211. doi:10.1016/j.jcat.2017.02.029.

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