The amphoteric character of Aluminium predetermines this element to form acidic as well as alkaline salts. All products appear white or clear like water.

Acidic

• Aluminium sulphate Al2(SO4)3 · 18 H₂O ( technical grade 14–15 H₂O). Dry powder or shells, appear gleaming white . Easy to store and to dissolve in water.
• Aluminium sulphate aqueous solution, Al₂(SO₄)₃ 
• Polyaluminiumchloride, aqueous solution ,
  well known as PAC, consists of monomeric, oligomeric and polymeric Aluminium compounds with the general formula:
  [Al₂(OH)_6-xCl_x · y H₂O]_n  y ≈ 2x n = 13–15
  These are products in the range of 25 to 45% basicity (OH/Al ratio of 0.75 to 1.35)
• Polyaluminiumchloride powder, [Al₂(OH)_6-xClx · y H₂O]_n
  The dried version of PAC is a light yellow powder which can easily be stored. Dissolving in water to prepare a solution needs some additional acid.
• Aluminium chloride aqueous solution, AlCl3  20% -30%
• Normally non coloured transparent liquid with relatively low viscosity.

Alkaline

• Sodium aluminate aqueous solution, NaAl(OH)₄.
  The products are a solution of  7-10% aluminium in caustic soda. The stability is limited due to the solubility of Al which depends on a couple of parameters.
• Other Aluminium salts
  Various anions in combination with Al, like nitrate for example.