Gypsum [Chemical formula, Physical, Chemical Properties and Reactions]

Chemical formula of gypsum is CaSo4.2H2O.

Physical Properties of Gypsum:

Properties Details
Cleavage Perfect, parallel to the basal plane
Color Colorless to white, may have shades of yellow or gray
Crystal System Monoclinic
Density 2.3 grams per cubic centimeter (g/cm³)
Hardness 2 on the Mohs scale of mineral hardness
Luster Vitreous to pearly
Refractive Index 1.52 to 1.54
Solubility Insoluble in water
Specific Gravity 2.2 to 2.3
Streak White
Transparency Translucent to transparent

Chemical Properties of Gypsum:

Property Details
Chemical Formula CaSO₄·2H₂O
Composition Calcium sulfate dihydrate (hydrated calcium sulfate)
Dehydration Temperature 120°C (248°F)
Flammability Non-flammable
Hygroscopicity Moderately hygroscopic
pH Slightly acidic (pH 5.5 to 6.5)
Reactivity Reacts with strong acids to form calcium sulfate
Solubility Soluble in water at room temperature
Thermal Conductivity Low

Reaction of gypsum

Alkali metal

Alkali metal Reaction with calcium oxide Reaction with sulfur trioxide
Lithium (Li) CaO + 2Li react and changes into Li2O + Ca Nill
Sodium (Na) CaO + 2Na react and changes into Na2O + Ca Na2SO4 + 10Na react and changes into 6Na2O + SO2
Potassium (K) CaO + 2K react and changes into K2O + Ca K2SO4 + 10K react and changes into 6K2O + SO2
Rubidium (Rb) CaO + 2Rb react and changes into Rb2O + Ca Rb2SO4 + 10Rb react and changes into 6Rb2O + SO2
Cesium (Cs) CaO + 2Cs react and changes into Cs2O + Ca Cs2SO4 + 10Cs react and changes into 6Cs2O + SO2

 

Alkaline Earth Metal

 

Alkaline Earth Metal Reaction
Beryllium (Be) Nill
Magnesium (Mg) CaSO4·2H2O + Mg react and changes into MgSO4·2H2O + Ca
Calcium (Ca) Nill
Strontium (Sr) Nill
Barium (Ba) CaSO4·2H2O + Ba react and changes into BaSO4 + Ca(OH)2

 

Transition Metal

Transition Metal Reaction with calcium oxide Reaction with sulfur trioxide
Iron (Fe) CaO + Fe react and changes into FeO + Ca Nill
Copper (Cu) CaO + Cu react and changes into CuO + Ca Nill
Silver (Ag) CaO + 2Ag react and changes into Ag2O + Ca Nill
Gold (Au) CaO + 2Au react and changes into Au2O + Ca Nill
Platinum (Pt) CaO + Pt react and changes into PtO + Ca Nill

 

Non-Transition Metal

Non-Transition Metal Reaction
Aluminum (Al) CaSO4·2H2O + 2Al react and changes into Al2(SO4)3 + Ca(OH)2
Zinc (Zn) CaSO4·2H2O + Zn react and changes into ZnSO4 + Ca
Lead (Pb) CaSO4·2H2O + Pb react and changes into PbSO4 + Ca
Tin (Sn) CaSO4·2H2O + Sn react and changes into SnSO4 + Ca
Antimony (Sb) CaSO4·2H2O + 2Sb react and changes into Sb2(SO4)3 + Ca

 

Non-Metal Element

Non-Metal Element Reaction
Carbon (C) CaSO4·2H2O + 2C react and changes into 2CO + SO2 + Ca(OH)2
Phosphorus (P) CaSO4·2H2O + 2P react and changes into 2H3PO4 + Ca
Sulfur (S) CaSO4·2H2O + S react and changes into CaS + 2H2O
Chlorine (Cl) CaSO4·2H2O + 2Cl react and changes into CaCl2 + H2SO4
Fluorine (F) Nill

 

Metalloid Element

 

Metalloid Element Reaction
Boron (B) CaSO4·2H2O + 2B react and changes into B2O3 + Ca(HSO4)2 + 2H2O
Silicon (Si) Nill
Germanium (Ge) Nill
Arsenic (As) CaSO4·2H2O + As2O3 react and changes into Ca3(AsO4)2 + 2SO2 + 2H2O
Antimony (Sb) CaSO4·2H2O + 2Sb react and changes into Sb2(SO4)3 + Ca