Basic aluminium salt explained

Basic aluminium (or basic aluminum) is the name of more than one functional group consisting of aluminium with one or two hydroxy groups attached.

Dihydroxyaluminium, Al(OH)₂, also known as dibasic aluminium, is monovalent, and known in these compounds:

• Dihydroxyaluminium acetate, (HO)₂AlCH₃CO₂, also known as aluminium monoacetate, basic aluminium monoacetate, dibasic aluminium acetate
• Dihydroxyaluminium sodium carbonate
• Aloglutamol, tris(hydroxymethyl)aminomethanegluconate dihydroxyaluminate
• Aluminium monostearate
• Carafate
• Sucralfate

Hydroxyaluminium, Al(OH), also known as monobasic aluminium or basic aluminium, is divalent, and known in these compounds:

• Hydroxyaluminium diacetate, HOAl(CH₃CO₂)₂, also known as aluminium diacetate, basic aluminium diacetate, basic aluminium acetate, monobasic aluminium acetate

Aluminium, Al, is trivalent. Aluminium triacetate, Al(CH₃CO₂)₃, is a complete molecule without any hydroxy groups, so it is not a "basic aluminium" compound.

Aluminium hydroxide, Al(OH)₃, aluminium with three hydroxy groups attached, is a complete molecule, so it is not a "basic aluminium" compound.

Aluminium acetate is a name for three salts in the solid state: dihydroxyaluminium aluminium acetate, hydroxyaluminium diacetate, and aluminium triacetate, Al(CH₃CO₂)₃. In aqueous solution, aluminium triacetate hydrolyses to form a mixture of the other two, so all solutions of all three can be referred to simply as "aluminium acetate", as the species co-exist and inter-convert in chemical equilibrium.