CALCIUM SULFIDE Property

Melting point:

2000 °C

Density 

2.6

refractive index 

2.12

solubility 

slightly soluble in H2O; insoluble in ethanol

form 

Powder

Specific Gravity

2.5

color 

White

Water Solubility 

Slightly soluble in water. Insoluble in alcohol.

Sensitive 

Moisture Sensitive

Merck 

14,1707

CAS DataBase Reference

20548-54-3(CAS DataBase Reference)

EPA Substance Registry System

Calcium sulfide (CaS) (20548-54-3)

Safety

Hazard Codes 

Xi,N

Risk Statements 

31-36/37/38-50

Safety Statements 

28-61

RIDADR 

UN 3179 4.1/PG 2

WGK Germany 

2

TSCA 

Yes

HazardClass 

4.3

PackingGroup 

III

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H228Flammable solid

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

H400Very toxic to aquatic life

Precautionary statements

P210Keep away from heat/sparks/open flames/hot surfaces. — No smoking.

P273Avoid release to the environment.

P302+P352IF ON SKIN: wash with plenty of soap and water.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

CALCIUM SULFIDE Chemical Properties,Usage,Production

Chemical Properties

CALCIUM SULFIDE is OFF-WHITE POWDER

Physical properties

Calcium sulfide is slightly soluble in water but insoluble in alcohol. It reacts with acids, producing hydrogen sulfide gas. Calcium sulfide is pale yellow to light gray with a bitter taste. It is hygroscopic, producing an odor of H2S in moist air.

Occurrence

Calcium sulfide occurs in nature as the mineral oldhamite. It has several applications. The ‘luminous’ calcium sulfide is used in phosphors, luminous paints and varnishes. Calcium sulfide also is used as an additive to lubri cants; and as a flotation agent in ore extraction.

Uses

Calcium sulfide is used in phosphors, lubricant additives and luminous paints. It reacts with elemental sulfur to give a lime-sulfur. Further, it is used in ore dressing and flotation agent. In addition to this, it is used as a depilatory in the tanning industry and in cosmetics.

Uses

Calcium sulfide may be used to remove heavy metals from wastewater.

Uses

CALCIUM SULFIDE is used in electron emitters. Luminous CaS used for making luminous paints or varnishes.

Preparation

Calcium sulfide can be prepared by the direct reaction of the elements, calcined in an inert atmosphere, at a 1:1.05 molecular ratio:
Ca＋S＋heat→CaS
This white material crystallizes in a cubic structurelike rock salt and the bonding is highly ionic. This is consistent with its description as an ionic solid. CaS can also be produced by the “carbothermic reduction” of calcium sulfate, which entails the conversion of carbon, usually as charcoal, to CO2:
CaSO4＋ 2C→CaS＋ 2CO2
This can react further:
3CaSO4＋ CaS→4CaO＋ 4SO2
Thus, this type of preparation cannot be used to prepare a pure CaS salt.
Calcium sulfide is available commercially as the pure sulfide as well as the polysulfide due to its extensive usage in the past as an insecticide both agriculturally and in home gardens.

General Description

Crystal structure of CaS is cubic. Electrical conductivity of calcium sufide in the temperature range of 650^oC-1000^oC was studied in great detail. It was concluded that CaS could be used as a potential electrolyte in a sulfur concentration cell.2