Sodium sulfide: Difference between revisions

{{short description|Chemical compound}}

|Verifiedfields=changed

|Watchedfields=changed

|verifiedrevid=455149914

|Name=Sodium sulfide

|OtherNames=Disodium sulfide

|ImageFile1=Natriumsulfid.jpg

|ImageFile2=Fluorite-unit-cell-3D-ionic.png

|Section1={{Chembox Identifiers

| CASNo = 1313-82-2

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo1_Ref = {{cascite|correct|CAS}}

| CASNo1 = 1313-83-3

| CASNo1_Comment = (pentahydrate)

| CASNo2_Ref = {{cascite|correct|CAS}}

| CASNo2 = 1313-84-4

| CASNo2_Comment = (nonahydrate)

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = YGR27ZW0Y7

| UNII1_Ref = {{fdacite|correct|FDA}}

| UNII1 = 6U55N59SZ2

| UNII1_Comment = (pentahydrate)

| UNII2_Ref = {{fdacite|correct|FDA}}

| UNII2 = C02T02993U

| UNII2_Comment = (nonahydrate)

| PubChem = 237873

| EINECS = 215-211-5

| UNNumber = 1385 (anhydrous)<br/>1849 (hydrate)

| RTECS = WE1905000

| ChEBI_Ref = {{ebicite|changed|EBI}}

| ChEBI = 76208

| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}

| ChemSpiderID = 14120

| SMILES = [Na+].[Na+].[S-2]

| InChI = 1/2Na.S/q2*+1;-2

| InChIKey = GRVFOGOEDUUMBP-UHFFFAOYAP

| StdInChI_Ref = {{stdinchicite|changed|chemspider}}

| StdInChI = 1S/2Na.S/q2*+1;-2

| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}

| StdInChIKey = GRVFOGOEDUUMBP-UHFFFAOYSA-N

}}

|Section2={{Chembox Properties

| Formula = Na₂S

| MolarMass = 78.0452 g/mol (anhydrous)<br/>240.18 g/mol (nonahydrate)

| Appearance = colorless, hygroscopic solid

| Odor = none

| Solubility = 12.4 g/100 mL (0 °C) <br> 18.6 g/100 mL (20 °C) <br> 39 g/100 mL (50 °C) <br> (hydrolyses)

| SolubleOther = insoluble in [[diethyl ether|ether]] <br> slightly soluble in [[ethanol|alcohol]]<ref>{{cite journal|last1=Kurzin|first1=Alexander V.|last2=Evdokimov|first2=Andrey N.|last3=Golikova|first3=Valerija S.|last4=Pavlova|first4=Olesja S.|date=June 9, 2010|title=Solubility of Sodium Sulfide in Alcohols|journal=J. Chem. Eng. Data|volume=55|issue=9|pages=4080–4081|doi=10.1021/je100276c}}</ref>

| Density = 1.856 g/cm³ (anhydrous) <br> 1.58 g/cm³ (pentahydrate) <br> 1.43 g/cm³ (nonohydrate)

| MeltingPtC = 1176

| MeltingPt_notes = (anhydrous) <br> 100 °C (pentahydrate) <br> 50 °C (nonahydrate)

| MagSus = &minus;39.0·10⁻⁶ cm³/mol

}}

|Section3={{Chembox Structure

| CrystalStruct = [[Antifluorite]] (cubic), [[Pearson symbol|''cF12'']]

| SpaceGroup = Fm<u style="text-decoration:overline">3</u>m, No. 225

| Coordination = Tetrahedral (Na⁺); cubic (S²⁻)

| LattConst_a =

| LattConst_alpha =

}}

|Section4={{Chembox Thermochemistry

| DeltaHf =

| Entropy =

| HeatCapacity =

|Section7={{Chembox Hazards

| ExternalSDS = [http://www.inchem.org/documents/icsc/icsc/eics1047.htm ICSC 1047]

| GHSPictograms = {{GHS05}} {{GHS06}} {{GHS07}} {{GHS09}}

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|302|311|314|400}}

| PPhrases = {{P-phrases|260|264|270|273|280|301+312|301+330+331|302+352|303+361+353|304+340|305+351+338|310|312|321|322|330|361|363|391|405|501}}

| NFPA-H = 3

| NFPA-F = 1

| NFPA-R = 1

| NFPA-S =

| FlashPt =

| AutoignitionPt = >

| AutoignitionPtC = 480

|Section8={{Chembox Related

| OtherAnions = [[Sodium oxide]]<br/>[[Sodium selenide]]<br/>[[Sodium telluride]]<br/>[[Sodium polonide]]

| OtherCations = [[Lithium sulfide]]<br/>[[Potassium sulfide]]<br>[[Rubidium sulfide]]<br>[[Caesium sulfide]]

| OtherFunction =

| OtherFunction_label =

| OtherCompounds = [[Sodium hydrosulfide]]

'''Sodium sulfide''' is a [[chemical compound]] with the [[chemical formula|formula]] [[Sodium ion|Na]]₂[[Sulfide|S]], or more commonly its [[hydrate]] Na₂S·9[[Water of crystallization|H₂O]]. 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 [[polysulfide]]s and commonly supplied as a crystalline mass, in flake form, or as a fused solid. They are water-soluble, giving strongly [[base (chemistry)|alkaline]] solutions. When exposed to moisture, Na₂S immediately hydrates to give [[sodium hydrosulfide]].

Some commercial samples are specified as Na₂S·''x''H₂O, 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.

The structures of sodium sulfides have been determined by [[X-ray crystallography]]. The nonahydrate features S2- hydrogen-bonded to 12 water molecules.<ref>{{cite journal |doi=10.1016/S0020-1693(00)86975-3 |title=Hydrogen Bonds in Na₂S·9D₂O: Neutron Diffraction, X-Ray Diffraction and Vibrational Spectroscopic Studies |date=1982 |last1=Preisinger |first1=A. |last2=Mereiter |first2=K. |last3=Baumgartner |first3=O. |last4=Heger |first4=G. |last5=Mikenda |first5=W. |last6=Steidl |first6=H. |journal=Inorganica Chimica Acta |volume=57 |pages=237–246 }}</ref> The pentahydrate consists of S^2- centers bound to Na⁺ and encased by an array of hydrogen bonds.<ref>{{cite journal |doi=10.1039/dt9840001275 |title=Hydrogen Bonds in Na₂S·5H₂O: X-ray Diffraction and Vibrational Spectroscopic Study |date=1984 |last1=Mereiter |first1=Kurt |last2=Preisinger |first2=Anton |last3=Zellner |first3=Andrea |last4=Mikenda |first4=Werner |last5=Steidl |first5=Heinz |journal=J. Chem. Soc., Dalton Trans. |issue=7 |pages=1275–1277 }}</ref> Anhydrous Na₂S, which is rarely encountered, adopts the [[antifluorite]] structure,<ref>{{cite journal | title = Gitterstruktur der oxyde, sulfide, selenide und telluride des lithiums, natriums und kaliums | journal = [[Zeitschrift für Elektrochemie und Angewandte Physikalische Chemie|Z. Elektrochem. Angew. Phys. Chem.]] | year = 1934 | volume = 40 | pages = 588–93 | author1 = Zintl, E | author2 = Harder, A | author3 = Dauth, B. | authorlink1 = eduard Zintl}}</ref><ref>Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. {{ISBN|0-19-855370-6}}.</ref> 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:<ref>{{ cite book | last1=Holleman | first1=A.F. | last2=Wiberg | first2=E. | title=Inorganic Chemistry | publisher = Academic Press | location = San Diego | year = 2001 | isbn=0-12-352651-5}}.</ref>

: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 [[tetrahydrofuran|THF]] with a catalytic amount of [[naphthalene]] (forming [[sodium naphthalenide]]):<ref>{{cite journal | doi = 10.1002/9780470132609.ch11 | volume = 29 | pages = 30–32 | author1 = So, J.-H | author2 = Boudjouk, P | last3 = Hong | first3 = Harry H. | last4 = Weber | first4 = William P. | title = Hexamethyldisilathiane | journal = [[Inorganic Syntheses|Inorg. Synth.]] | date = 2007 | isbn = 978-0-470-13260-9}}</ref>

: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:

:{{Chem|S|2−}} + {{H+}} → {{Chem|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]] ({{Chem|SH|−}}). An aqueous solution contains a significant portion of sulfide ions that are singly protonated.

:{{Chem|S|2−}} + {{H2O}} {{EqmR}} {{Chem|SH|−}} + {{OH-}}

:{{Chem|SH|−}} + {{H2O}} {{EqmL}} {{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]]:<ref>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}}</ref>

:Na₂S + 4 H₂O₂ → 4 {{H2O}} + Na₂SO₄

Upon treatment with [[sulfur]], [[Sodium polysulfide|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, [[Petroleum extraction|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 [[thioether]]s:

:Na₂S + 2 RX → R₂S + 2 NaX

Even [[aryl]] halides participate in this reaction.<ref>Charles C. Price, Gardner W. Stacy "p-Aminophenyldisulfide" Org. Synth. 1948, vol. 28, 14. {{doi|10.15227/orgsyn.028.0014}}</ref> 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 reaction|Sandmeyer]] type reactions.<ref>{{cite journal|last=Khazaei|display-authors=etal|date=2012|title=synthesis of thiophenols|journal=Synthesis Letters |volume=23|issue=13|pages=1893–1896|doi=10.1055/s-0032-1316557|s2cid=196805424 }}</ref>

====Reducing agent====

Aqueous solution of sodium sulfide will reduce [[Nitro compound|nitro groups]] to [[amine]]. This conversion is applied to production of some [[azo dye]]s since other reducible groups, e.g. [[Azo compound|azo group]], remain intact.<ref>{{cite journal|last=Yu|display-authors=etal|date=2006|title=Syntheses of functionalized azobenzenes|journal =Tetrahedron|volume= 62|issue=44|pages=10303–10310|doi=10.1016/j.tet.2006.08.069}}</ref> The reduction of nitro aromatic compounds to amines using sodium sulfide is known as the [[Zinin reaction]] in honor of its discoverer.<ref>{{cite journal

| title = Beschreibung einiger neuer organischer Basen, dargestellt durch die Einwirkung des Schwefelwasserstoffes auf Verbindungen der Kohlenwasserstoffe mit Untersalpetersäure | language = German

|trans-title= Description of some new organic bases, represented by the action of hydrogen sulphide on hydrocarbons with sub-nitric acid

| first = N. | last = Zinin | authorlink = Nikolay Zinin

| journal = [[Journal für Praktische Chemie]]

| volume = 27

| issue = 1

| pages = 140–153

| year = 1842

| url =https://zenodo.org/record/1427792

| doi = 10.1002/prac.18420270125}}</ref> Hydrated sodium sulfide reduces [[1,3-dinitrobenzene]] derivatives to the [[3-nitroaniline]]s.<ref>{{OrgSynth | author = Hartman, W. W.; Silloway, H. L. | title = 2-Amino-4-nitrophenol | volume = 25|year=1945|page= 5|doi= 10.15227/orgsyn.025.0005 }}</ref>

====Other reactions====

Sulfide has also been employed in [[Photocatalysis|photocatalytic]] applications.<ref>{{cite journal|author1=Savateev, A. |author2=Dontsova, D. |author3=Kurpil, B. |author4=Antonietti, M. |date=June 2017|title=Highly crystalline poly(heptazine imides) by mechanochemical synthesis for photooxidation of various organic substrates using an intriguing electron acceptor – Elemental sulfur|journal=Journal of Catalysis|volume= 350|pages=203–211|doi=10.1016/j.jcat.2017.02.029}}</ref>

<!-- notable?Sodium sulfide is an active ingredient in some over-the-counter ingrown toenail relief products.<ref>{{Federal Register|68|24347}}</ref>-->

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.

{{reflist}}

{{Sodium compounds}}

{{Sulfides}}

[[Category:Fluorite crystal structure]]