Aluminium sulfate ( Papermaker's alum )

                        Aluminium sulfate is otherwise known as papermaker's alum. However it is not technically an alum. It's properties are quite different from other alums. Most of the industrial flocculation done with alum is aluminium sulfate.

Chrome alum

                Chrome alum is otherwise known as Chromium alum. Chemical formula is              KCr(SO₄)₂.12H₂O. It is a dark violet crystalline double sulfates of chromium and potassium. The dark violet compound is used in tanning and can be added to other alum to grow lavender or purple crystals.

Ammonium alum

             Ammonium alum is otherwise known as Ammonium aluminium sulfate. Chemical formula is 

 NH₄Al(SO₄)₂.12H₂O. It is a white crystalline double sulfates of aluminium. Ammonium alum finds applications in tanning, dyeing textiles, making textiles flame retardant in the manufacture of porcelin cements and vegetable glues, in water purification and in some deodorants.

Soda alum

                        Soda alum is otherwise known as sodium aluminium sulfate. Chemical formula is NaAl  (SO₄)₂.12H₂O. It is very soluble in water.And is extremely difficult to purify. It is used in baking powder and as an acidulent in food.

Potash alum ( Potassium aluminium sulfate )

                  Potassium aluminium sulfate is otherwise known as potash alum or potassium alum. Chemical formula KAl (SO₄)₂.12H₂O . Naturally occuring mineral potash alum is known as alum - (K). Other potassium aluminium sulfate minerals are alunite and kalinite. It is used as an astringent and antisepsis in various food preparation processes such as a flocculant for water purification among other things.

Alum

                   Alums are double sulphate salts. Alum is in reference to potassium alum. It is a compound of hydrated potassium aluminium sulfate with chemical formula KAl(SO₄)₂.12H₂O. Any of the compound with the empriocal formula AB(SO₄)₂.12H₂O.are considered to be alum. A is a monovalent cation such as potassium or ammonium. B is a trivalent metal ion such as aluminium or chromium. Some times alum is seen in its crystalline form, although it is most often sold as a powder.

Types of alum :

• Potash alum
• Soda alum
• Ammonium alum
• Aluminum sulfate
• Selenate alum
• Chrome alum

Amalgam

    An alloy of mercury with one or more other metals. Almost all metals can form amalgams with mercury. ( excepting iron  ). Amalgam may be solid or liquid.Silver-mercury amalgam are important in dentistry. Gold-mercury amalgam is used in the extraction of gold from ore.

Types of amalgam : 

• Dental amalgam
• Potassium amalgam
• sodium amalgam
• Ammonium amalgam
• Aluminium amalgam
• Thallium amalgam
• Tin amalgam 
• Gold amalgam