What Is Aluminium Phosphate Formula Properties Reactions and Applications
Aluminium Phosphate, or Aluminium (III) Phosphate, is an inorganic salt that is found in several minerals and is often used as a catalyst. It is also used in the pharmaceutical industry for manufacturing chemotherapeutic drugs. It occurs naturally in the form of the mineral berlinite. It is prepared chemically when soluble Aluminium salts are exposed to alkaline conditions. It is represented as AlPO4, which consists of hydrated Aluminium Orthophosphate. The Aluminium Phosphate solutions form polymeric aggregates wherein equilibrium is reached very slowly. It forms soluble Aluminium salts and Phosphoric acid by slowly reacting with Gastric acid.
However, it absorbs the bile acids weaker than Aluminium Hydroxide. Here, we will learn what is Aluminium Phosphate, what is the formula for Aluminium Phosphate, what is Aluminium Phosphate used for, and the properties of Aluminium Phosphate.
Aluminium Phosphate Structure- AlPO4
Aluminium Phosphate generally occurs as an anhydrous salt. However, its dihydrate and pentahydrate structures occur as well, which are represented as AlPO4.2H2O and AlPO4.5H2O.
The Aluminium Phosphate compound is formed by the Phosphate anion and Aluminium cation. Its anhydrous salt structure is much similar to several other minerals like quartz and has a trigonal crystal structure. However, its dihydrate form has a structure similar to NaCl in which 6 cations are coordinated to 6 anions. The structure of Aluminium Phosphate AlPO4 is shown below. This representation is commonly used for organic molecules.
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Chemical Formula of Aluminium Phosphate
Let us take a look at what is the chemical formula for aluminium phosphate.
Aluminium Phosphate is also called Aluminium Monophosphate or Mono-Aluminium Phosphate. It is formed by the Phosphate anion PO43-, and the Aluminium cation Al3+. Hence, the chemical or molecular formula of Aluminium Phosphate is AlPO4.
It occurs as a white crystalline powder. However, it is a colourless liquid in its aqueous form. It is insoluble in water and occurs in the form of a mineral berlinite. Aluminium phosphate is found in minerals like variscite and meta-variscite in its dihydrate form. Since it has piezoelectric properties, it is widely used in the electronic and electrical industries.
Now that you know about what is Aluminum Phosphate and what is the chemical formula for Aluminum Phosphate, let us take a look at some of its properties.
Physical Properties of Aluminium Phosphate AlPO4
Let us now discuss the physical properties of Aluminium Phosphate AlPO4 .
Chemical Properties of Aluminium Phosphate AlPO4
Now let us go through the chemical properties of Aluminium Phosphate AlPO4.
Aluminium Phosphate reacts with Hydrochloric Acid to form Aluminium Trichloride and Phosphoric acid. The reaction is as follows.
AlPO4 + 3HCl → AlCL3 + H3PO4
Aluminium Phosphate reacts with Magnesium Chloride to form Magnesium Phosphate and Aluminium Trichloride. The reaction is given as follows.
2AlPO4 + 3MgCl2 → Mg3(Po4)2 + 2AlCl3
FAQs on Aluminium Phosphate Structure Properties Preparation and Uses
1. What is aluminium phosphate?
Aluminium phosphate is an ionic compound with the chemical formula AlPO4, formed from aluminium ions and phosphate ions. It consists of Al3+ and PO43- ions combined in a 1:1 ratio to balance charges. It is typically a white solid and occurs naturally as the mineral berlinite. In chemistry, aluminium phosphate is studied as a sparingly soluble salt and is also used in ceramics, vaccines (as an adjuvant), and dental materials.
2. What is the chemical formula for aluminium phosphate?
The chemical formula for aluminium phosphate is AlPO4. The formula is obtained by balancing the charges of Al3+ and PO43- so that the total positive and negative charges cancel out. Since both ions have charges of 3 (but opposite signs), they combine in a 1:1 ratio to form a neutral compound.
3. Is aluminium phosphate soluble in water?
Aluminium phosphate is sparingly soluble in water and is generally considered insoluble under normal conditions. According to solubility rules, most phosphates (PO43-) are insoluble except those of alkali metals and ammonium. As a result, AlPO4(s) forms a solid precipitate when aluminium ions react with phosphate ions in aqueous solution.
4. How is aluminium phosphate prepared in the laboratory?
Aluminium phosphate can be prepared by a precipitation reaction between a soluble aluminium salt and a soluble phosphate salt. A common example is:
AlCl3(aq) + Na3PO4(aq) → AlPO4(s) + 3NaCl(aq)
Steps involved:
- Prepare aqueous solutions of aluminium chloride and sodium phosphate.
- Mix the two solutions together.
- A white precipitate of AlPO4(s) forms.
- Filter, wash, and dry the precipitate.
5. What type of compound is aluminium phosphate?
Aluminium phosphate is primarily an ionic compound composed of metal cations and polyatomic anions. It contains:
- Al3+ (a metal cation)
- PO43- (a polyatomic anion)
6. What is the molar mass of aluminium phosphate?
The molar mass of aluminium phosphate (AlPO4) is approximately 121.95 g·mol-1. It is calculated as follows:
- Al = 26.98 g·mol-1
- P = 30.97 g·mol-1
- O4 = 4 × 16.00 = 64.00 g·mol-1
7. What happens when aluminium phosphate reacts with acids?
Aluminium phosphate reacts with strong acids to form soluble aluminium salts and phosphoric acid. For example, with hydrochloric acid:
AlPO4(s) + 3HCl(aq) → AlCl3(aq) + H3PO4(aq)
In this reaction:
- The solid phosphate dissolves.
- Aluminium forms a soluble salt.
- Phosphate is converted into phosphoric acid (H3PO4).
8. How do you write the ionic equation for the formation of aluminium phosphate?
The net ionic equation for the formation of aluminium phosphate is:
Al3+(aq) + PO43-(aq) → AlPO4(s)
This equation shows:
- Combination of aluminium ions and phosphate ions.
- Formation of an insoluble precipitate.
- Charge balance: +3 and −3 cancel to form a neutral compound.
9. What are the uses of aluminium phosphate?
Aluminium phosphate is used in vaccines, ceramics, dental cements, and antacids. Key applications include:
- As a vaccine adjuvant to enhance immune response.
- In ceramics due to its heat resistance.
- In dental materials for cement formulations.
- In some pharmaceutical preparations as a buffering or antacid agent.
10. What is the difference between aluminium phosphate and aluminium sulphate?
The main difference is that aluminium phosphate (AlPO4) is largely insoluble in water, whereas aluminium sulphate (Al2(SO4)3) is soluble. Key differences include:
- Anion present: PO43- vs SO42-
- Solubility: AlPO4 is sparingly soluble; Al2(SO4)3 dissolves readily in water.
- Uses: Aluminium sulphate is commonly used in water treatment, while aluminium phosphate is used in vaccines and ceramics.
