Calcium sulfide: Difference between revisions

| Name = Calcium sulfide

| ImageFile = Calcium-sulfide-3D-balls.png

<!-- | ImageSize = 125px -->

| ImageName = Calcium sulfide

| IUPACName = Calcium sulfide

| OtherNames = Calcium monosulfide,<br/>Hepar calcies,<br/>Sulfurated lime<br/>Oldhamite

| Section1 = {{Chembox Identifiers

| ChemSpiderID = 8373113

| UNII = <!-- blanked - oldvalue: 1MBW07J51Q -->

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

| PubChem = 10197613

| RTECS =

| EINECS = 243-873-5

| Section2 = {{Chembox Properties

| Formula = CaS

| MolarMass = 72.143 g/mol

| Appearance = white crystals <br> [[hygroscopic]]

| Density = 2.59 g/cm³

| Solubility = slightly soluble

| SolubleOther = insoluble in [[alcohol]] <br> reacts with [[acid]]

| MeltingPt = 2525 °C

| BoilingPt =

| RefractIndex = 2.137

| Section3 = {{Chembox Structure

| CrystalStruct = [[Halite]] (cubic), [[Pearson symbol|cF8]]

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

| Coordination = Octahedral (Ca²⁺); octahedral (S^2–)

| LattConst_a =

| Section7 = {{Chembox Hazards

| ExternalMSDS =

| MainHazards = H₂S source

| EUClass = Irritant ('''Xi''')<br/>Dangerous for the environment ('''N''')

| EUIndex = 016-004-00-0

| NFPA-H = 2

| NFPA-F = 1

| NFPA-R = 1

| RPhrases = {{R31}}, {{R36/37/38}}, {{R50}}

| SPhrases = {{S2}}, {{S28}}, {{S61}}

| Section8 = {{Chembox Related

| OtherAnions = [[Calcium oxide]]

| OtherCations = [[Magnesium sulfide]]<br/>[[Strontium sulfide]]<br/>[[Barium sulfide]]

| Function = [[sulfide]]s

| OtherFunctn = [[Sodium sulfide]]

'''Calcium sulfide''' is the [[chemical compound]] with the formula CaS. This white material crystallizes in cubes like rock salt. CaS has been studied as a component in a process that would recycle [[gypsum]], a product of [[flue gas desulfurization]]. Like many salts containing [[sulfide]] ions, CaS typically has an odour of [[hydrogen sulfide|H₂S]], which results from small amount of this gas formed by hydrolysis of the salt.

In terms of its atomic structure, CaS crystallizes in the same motif as [[sodium chloride]] indicating that the bonding in this material is highly [[Ionic bond|ionic]]. The high melting point is also consistent with its description as an ionic solid. In the crystal, each [[sulfide|S^{2<nowiki>&minus;</nowiki>}]] ion is surrounded by an [[octahedron]] of six Ca²⁺ ions, and complementarily, each Ca²⁺ ion surrounded by six S^{2<nowiki>&minus;</nowiki>} ions.

CaS is produced by "carbothermic reduction" of [[calcium sulfate]], which entails the conversion of carbon, usually as charcoal, to [[carbon dioxide]]:

:3 CaSO₄ + CaS → 4 CaO + 4 [[sulfur dioxide|SO₂]]

In the second reaction the [[sulfate]] (+6 [[oxidation state]]) oxidizes the [[sulfide]] (-2 oxidation state) to [[sulfur dioxide]] (+4 oxidation state), while it is being reduced to sulfur dioxide itself (+4 oxidation state).

CaS is also a byproduct in the [[Leblanc process]].

[[Milk of lime]], Ca(OH)₂, reacts with elemental sulfur to give a "[[lime sulfur|lime-sulfur]]", which has been used as an [[insecticide]]. The active ingredient is probably a calcium [[polysulfide]], not CaS.<ref>Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.</ref>

: CaS + 2 HCl → CaCl₂ + H₂S

Oldhamite is the name for mineralogical form of CaS. It is a rare component of some meteorites and has scientific importance in solar nebula research. Burning of the coal dumps can also produce such compound.

<references/>

[[Category:Sulfides]]

[[ar:كبريتيد الكالسيوم]]

[[ca:Sulfur de calci]]

[[cs:Sulfid vápenatý]]

[[de:Calciumsulfid]]

[[el:Θειούχο ασβέστιο]]

[[fr:Sulfure de calcium]]

[[ko:황화 칼슘]]

[[it:Solfuro di calcio]]

[[hu:Kalcium-szulfid]]

[[nl:Calciumsulfide]]

[[ja:硫化カルシウム]]

[[pl:Siarczek wapnia]]

[[pt:Sulfeto de cálcio]]

[[ru:Сульфид кальция]]

[[sr:Калцијум-сулфид]]

[[zh:硫化钙]]