JEE Main & Advanced Chemistry Organic Chemistry: Some Basic Principles & Techniques / कार्बनिक रसायन : कुछ मूलभूत सिद्धांत एवं तकन Occurrence of Metals

Occurrence of Metals

Category : JEE Main & Advanced

Element which have low chemical reactivity generally occur native or free or metallic state. e.g. \[Au,\,Pt,\,\]noble gas etc. Element which are chemically reactive, generally occur in the combined state. e.g. halogens, chalcogens etc. The natural materials in which the metals occur in the earth are called minerals. The mineral from which the metal is conveniently and economically extracted is called an ore. All the ores are minerals but all  minerals cannot be ores. Ores may be divided into four groups,            

(1) Metallic core (siderophile) of the earth crust contains (Mn, Fe, Co, Ni, Cu, Ru, Rb, Pd, Ag, Re, Os, Ir, Pt, Au). Entire composition of metals in earth crust may be given as,            

Al (8.3%); Ca(3.6%); Na (2.8%); K (2.6%); Mg (2.1%); Ti (0.4%); Mn (0.1%); Fe (5.1%) other metals (0.1%).            

(i) Native ores : These ores contain metals in free state, e.g., silver, gold, platinum, mercury, copper, etc. These are found usually associated with rock or alluvial materials like clay, sand, etc. sometimes lumps of pure metals are also found. These are termed nuggets. Iron is found in free state as meteroites which also have 20 to 30% nickel.            

(ii) Sulphurised and arsenical ores : These ores consist of sulphides and arsenides in simple and complex forms of metals. Important ores of this group are

Metal Name of the ore Composition
Pb Galena PbS
Zn Zinc blende ZnS
Hg Cinnabar HgS
Ag Argentite or silver glance Pyrargyrite or ruby silver Ag2S3Ag2S.Sb2S3
Fe Iron pyrites FeS2
Ni Kupfer nickel NiAs
Cu Copper pyrites Chalcocite or Copper glance CuFeS2Cu2S

(iii) Oxidised ores : In these ores, metals are present as their oxides or oxysalts such as carbonates, nitrates, sulphates, phosphates, silicates, etc.

Important ores of this group are listed below,            


Haematite Fe2O3
Magnetite Fe3O4
Limonite Fe2O3.3H2O
Bauxite Al2O3.2H2O
Corundum Al2O3
Diaspore Al2O3.H2O
Chromite FeO.Cr2O3
Chromeochre Cr2O3
Tinstone (Cassiterite) SnO2  
Chrysoberyl BeO.Al2O3  
Cuprite (Ruby copper) Cu2O  
Pyrolusite MnO2  
Zincite ZnO  
Rutile TiO2
Ilmenite FeO.TiO2


Magnesite MgCO3  
Lime stone CaCO3  
Dolomite CaCO3.MgCO3  
Calamine ZnCO3  
Malachite CuCO3.Cu(OH)2
Azurite Cu(OH)2.2CuCO3
Cerussite PbCO3  
Siderite FeCO3  


 Chile saltpetre NaNO3
 Salt petre  KNO3


Epsom salt MgSO4.7H2O  
Barytes BaSO4  
Gypsum CaSO4.2H2O  
Glauber?s salt Na2SO4.10H2O  
Anglesite PbSO4  
Kainite KCl.MgSO4.3H2O
Schonite K2SO4.MgSO4.6H2O
Polyhalite K2SO4.MgSO4.CaSO4.2H2O

Phosphates and Silicates

Lepidolite (an ore of lithium) (Li, Na, K)2 Al2(SiO3)3 (F,OH)2
Petalite (an ore of lithium) LiAl(Si2O5)2
Triphylite (an ore of lithium) (Li, Na)3PO4, (Fe, Mn)3 (PO4)2
Beryl (an ore of berylium) 3BeO. Al2O3.6SiO2  
Willemite Zn2SiO4  
China clay Al2O3.2SiO2.2H2O  
Chlor-apatite 3Ca3(PO4)2.CaCl2  
Mica K2O.3Al2O3.6SiO2.2H2O  
Fluor-apatite 3Ca3(PO4)2.CaF2  
Felspar KAlSi3O8  
Talc Mg2(Si2O5).Mg(OH)2  
Asbestos CaMg3.(SiO3)4  

(iv) Halide ores : Metallic halides are very few in nautre. Chlorides are most common. For example.            

Common salt \[NaCl\];            

Horn silver \[AgCl\]            

Carnallite \[KCl.\,MgC{{l}_{2}}.6{{H}_{2}}O\]            

The important fluoride ores are        

Fluorspar \[Ca{{F}_{2}}\];        

Cryolite \[N{{a}_{3}}Al{{F}_{6}}\]

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