8/6/2019 Sulfides

1/7

SULFIDES

IntroductionInorganic sulfides are compounds of various metals with sulfur. Sulfides are generally notthought of as high temperature materials, but at least 30 metallic sulfides display refractory

properties which indicate potential uses at elevated temperatures. Some of the refractorysulfides are more stable than oxides in vacuum, giving rise to interesting potential applications.

PreparationSulfides generally are prepared by any of six preparative schemes:

1. Direct reaction of the elements.

Be + S BeS

2. Reaction of metal oxides or carbonates with a sulfur compound.

CaO + H2S CaS + H2OLi2CO3 + H2S Li2S + CO2 + H2O

3. Reduction of a higher sulfide.2Ce2S3 + 2CeH3 6CeS + 3H2

4. Reaction of a metal hydride with a sulfur compound.

2UH3 + 4H2S 2US2 + 7H2

5. Reduction of metallic sulfates.

BaSO4 + 4C BaS + 4CO

6. Reaction of a metallic halide with a sulfur compound.

2LaCl3 + 3H2S La2S3 + 6HCl

CERAC employs all of these routes, plus proprietary developments, to prepare the one of thelargest families of pure or mixed sulfides available.

back to top

General Properties

Many sulfides have melting points above those of oxides.

Sulfides can either be "salt-like" (e.g., the alkaline earth sulfides) or "hard-metal like"(e.g., the refractory sulfides).

Sulfides are generally hydrolyzed by water.

Sulfides generally oxidize readily in moist air at ambient temperature or in dry air atelevated temperature.

Some sulfides possess semi-metallic character and have potentially valuable electronicproperties.

back to top

General Suggested Uses

Tantalum and niobium sulfides have low friction coefficients and can be used aslubricants for optical and sensitive instruments.

Rare earth sulfides are semi-conductors and have been used in thermoelectric devices.

Alkaline earth sulfides plus those of calcium and zinc are used for phosphor

compositions.

http://www.cerac.com/pubs/proddata/sulfides.htm#top%23tophttp://www.cerac.com/pubs/proddata/sulfides.htm#top%23tophttp://www.cerac.com/pubs/proddata/sulfides.htm#top%23tophttp://www.cerac.com/pubs/proddata/sulfides.htm#top%23top

8/6/2019 Sulfides

2/7

Molybdenum and tungsten sulfides are widely used, non-graphitic commerciallubricants.

back to top

Parts FabricationNumerous sulfides can be fabricated by various techniques (e.g., hot-pressing, isostaticpressing) without added binders to form dense bodies. Please contact the CERAC salesdepartmentfor more information.

back to top

Availability and Ordering InformationCERAC prepares a comprehensive selection of sulfides. Small lots are promptly available fromstock for experimental or test purposes. Production quantities of many sulfides are alsoavailable from stock. Large amounts of other sulfides are produced to customer's specification

for rapid shipment. Mixed sulfides (e.g., Li2S-FeS2), non-stoichiometric compositions or specialpurities and particle sizes can be custom manufactured. Please contact oursales departmentwith your exact specifications.

back to top

Sulfide Applications

Table 1: Sulfide Applications

Application Typical Sulfides Forms UsedBatteries

Lithium

CobaltIron

Nickel

Powders

Phosphor IngredientsStrontium

ZincCadmium

Powders

Lubricants and

Lubricant Addditives

Molybdenum

NiobiumCopper

Tantalum

Aerosol CansSputtering Targets

Powders

PigmentsCadmium

CeriumCopper

Powders

Ceramic Coatings Cobalt Powders

Photovoltaic Materials CadmiumPowders

Sputtering Targets

Industrial Strontium Powders

Infrared FiltersAntimony

Cadmium

Evaporation Materials

Sputtering Targets

http://www.cerac.com/pubs/proddata/sulfides.htm#top%23topmailto:ceracsales@beminc.commailto:ceracsales@beminc.comhttp://www.cerac.com/pubs/proddata/sulfides.htm#top%23topmailto:ceracsales@beminc.comhttp://www.cerac.com/pubs/proddata/sulfides.htm#top%23tophttp://www.cerac.com/pubs/proddata/sulfides.htm#top%23topmailto:ceracsales@beminc.commailto:ceracsales@beminc.comhttp://www.cerac.com/pubs/proddata/sulfides.htm#top%23topmailto:ceracsales@beminc.comhttp://www.cerac.com/pubs/proddata/sulfides.htm#top%23top

8/6/2019 Sulfides

3/7

The wide variety of sulfides available from CERAC has resulted from the numerous and largelyunrelated applications for these products. In many individual applications and with manyindividual customers, CERAC has developed products specifically for existing or newapplications. In fact, CERAC's product line has grown largely in response to customerrequirements. CERAC highly values these customer relationships and encourages any and allquestions, comments and suggestions related to the performance of CERAC sulfides in specific

applications.

Table 1 provides a glimpse of some of the recognized sulfide applications and the type ofCERAC products suitable for use in each case. For example, phosphor, battery and pigmentapplications usually require fine powders while numerous thin film applications require the useof sputtering targets or evaporation materials.

The scope of sulfide applications is continually changing and evolving. While zinc and cadmiumsulfides have a lengthy history of use in cathode ray tubes, strontium sulfide has only recentlybecome of importance in conversion of infrared radiation to visible light. Also, various sulfideshave come under recent scrutiny as new battery materials, largely due to the relatively stableforms of metal sulfides in multiple oxidation states and to environmental acceptabilities. Thesebattery developments extend from specialized military and industrial uses to evaluations

directed toward the propulsion of electric vehicles.

In summary, present and future sulfide applications are derived mainly from the diverseproperties exhibited by this family of products. For example, many sulfides exhibit "semimetallic"behavior, giving rise to electronic applications. Some are highly refractory, with melting pointsexceeding those of oxides, and are stable during thin film formation by vacuum deposition.Others have crystal structures and very high lubricities.

back to top

Table 2: Typical Properties of Sulfides

Sulfide Of Formula ColorTheo.

Density,g/cm3

MeltingPoint, C

Crystal Form

Aluminum Al2S3 yellow-off white 2.55 1100 hexagonal

Antimony Sb2S3 black 4.63 550 orthorhombic

Arsenic As2S3 yellow or red 3.52 325 monoclinic

Barium BaS grey-white 4.33 2200* cubic

Beryllium BeS grey-white 2.47 2200* cubic

Bismuth Bi2S3 brown-black 6.81 685 orthorhombic

Boron B2S3 white 1.55 310 monoclinic

http://www.cerac.com/pubs/proddata/sulfides.htm#top%23tophttp://www.cerac.com/pubs/proddata/sulfides.htm#top%23top

8/6/2019 Sulfides

4/7

Cadmium CdS yellow-red 4.82 1750 hexagonal

Calcium CaS white-pink 2.61 72000 cubic

Cerium CeS gold 5.93 2450 cubic

Cerium Ce2S3 red 5.2 1890 orthorhombic

Cerium Ce2O2S yellow 6.11 1950 hexagonal

Chromium Cr2S3 brown-black 3.92 1550 hexagonal

Cobalt CoS black 5.83 1210 hexagonal

Cobalt CoS2 black 4.8 - cubic

Copper Cu2S black 5.97 1100 orthorhombic

Copper CuS black 4.68200

decomp.hexagonal

Dysprosium Dy2S3 red-brown 6.55 1480 orthorhombic

Erbium Er2S3 yellow 6.21 1730 monoclinic

Europium EuS black 5.74 - cubic

Gadolinium Gd2S3 red-brown 6.19 1885 orthorhombic

Gallium Ga2S3 white 3.5 1250 cubic

Germanium GeS black 4.24 530 orthorhombic

Germanium GeS2 white 3.03 800 orthorhombic

Hafnium HfS2 red-brown 6.03 - hexagonal

Holmium Ho2S3 yellow 6.07 - monoclinic

Indium In2S yellow-black 5.87 655 no system

8/6/2019 Sulfides

5/7

Indium InS red-brown 5.18 695 orthorhombic

Indium In2S3 orange 4.65 1050 cubic

Iron FeS black-brown 4.84 1190 hexagonal

Iron FeS2 black 4.87425

decompcubic

Lanthanum La2S3 yellow 4.91 2150 no system

Lanthanum LaS2 yellow-brown 4.9 1650 cubic

Lanthanum La2O2S white 5.75 1980 hexagonal

Lead PbS black 7.5 1115 cubic

Lithium Li2S white 1.63 975 cubic

Lutetium Lu2S3 light grey 6.26 - rhombohedral

Magnesium MgS white 2.86 2000 cubic

Manganese MnS green 3.99 1615 cubic

Mercury HgS black 8.1 1450 hexagonal

Molybdenum MoS2 black 4.8 1815 hexagonal

Neodymium Nd2S3 green 5.49 - orthorhombic

Nickel NiS black 5.41 795 hexagonal

Niobium NbS1.75 blue-black 4.58 - hexagonal

Potassium K2S yellow 1.84 840 cubic

Praseodymium Pr2S3 brown 5.31 1795 orthorhombic

Rhenium Re2S7-H2O black 4.87 tetragonal

8/6/2019 Sulfides

6/7

Samarium Sm2S3 red-brown 5.84 1900 orthorhombic

Scandium Sc2S3 yellow 2.93 1775 cubic

Silicon SiS2 white 2.06 sublimes orthorhombic

Silver Ag2S black 7.27 825 monoclinic

Sodium Na2S white 1.89 1180 cubic

Strontium SrS pink 3.67 2000* cubic

Terbium Tb2S3 red 6.35 - orthorhombic

Tantalum TaS2 black 6.91 1300* hexagonal

Thallium Tl2S blue-black 8.39 260 hexagonal

Thorium ThS2 brown-black 7.36 2000* orthorhombic

Thulium Tm2S3 yellow-green 6.34 - monoclinic

Tin SnS grey-black 5.08882

decomp.orthorhombic

Tin SnS2 yellow 4.5 882 orthorhombic

Titanium TiS2 gold 3.28 2000* hexagonal

Tungsten WS2 metallic-blue-grey 7.73 1130 hexagonal

Uranium US2 grey-black 4.7 1850 tetragonal

Vanadium V2S3 black 4.7 1930 no system

Ytterbium Yb2S3 yellow 6.07 - hexagonal

Yttrium Y2S3 yellow 3.86 1600 monoclinic

8/6/2019 Sulfides

7/7

Yttrium Y2O2S grey-white 4.92 2120 hexagonal

Zinc ZnS white or yellow 4.1 1850 cubic

Zirconium ZrS2 brown 3.82 1550 hexagonal

# The data listed are selected from reliable literature and are only indicative. No guarantees ofaccuracy are implied

* Melting points are much higher than listed, but no accurate measurements have been made.

- Indicates data not available