Sulfur, Sulfate and Sulfite

Chemicals have very unique names. Sulfate (Sulphate), sulfite (Sulphite), and sulfur (Sulphur) are three chemicals with very different chemical and physical properties. A chemist or anybody who is familiar with chemicals may have no problem in distinguishing the differences between these 3 chemicals, but for someone who is not familiar these names sound somewhat the same. Let’s find out their differences.

What is Sulfur (Sulphur)?

Sulfur is a non-metallic element. The chemical symbol of Sulfur is S. it is found in numerous compounds and in various forms. Atomic number of sulfur is 16. In the pure form, Sulfur can have many physical forms. Therefore, it is called an allotropic element. The most common is the crystalline yellow color solid which is very brittle. The element is extremely reactive and has many applications. It is used in gun powder, in insecticides and in prescription drugs etc.

What is Sulfate (Sulphate)?

Sulfate is an Oxy-anion of Sulfur (Oxy-anion is Oxygen containing negative ion). Even if you are not familiar with Sulfate you must have heard about Sulfuric acid. Sulfuric acid is made up of two H+ ions and one sulfate ion. The empirical formula of the chemical is SO₄^2- . It is a polyatomic anion. In a sulfate ion, Sulfur atom is the central atom and four Oxygen atoms are covalently bound to the Sulfur atom. Two Oxygen atoms are bound by double bonds and the other two are singly bound. The singly bound Oxygen atoms originally contain a Hydrogen atom in each of them. When the sulfate ion is made they release H+ and carry negative charges. The geometry of Sulfate ion is tetrahedral where Oxygen atoms are placed in the 4 corners of the tetrahedron.

What is Sulfite (Sulphite)?

Sulfite is another Oxy-anion of Sulfur. It also contains two negative charges similar to Sulfate ion. The difference lies in the number of atoms present in the ion. Sulfite has Three Oxygen atoms doubly bonded to the central Sulfur atom. When the H+ ions are incorporated, Sulfite becomes Sulfurous acid. This acid is relatively weaker than the Sulfuric acid. The geometry of this anion is trigonal pyramidal. The Oxygens atoms are at the three edges, and a lone pair of electrons is on the top. The empirical formula of sulfite ion is SO₃^2-.

Both these sulfur anions are commonly used in food preservation.

What is the difference between Sulfur, Sulfate, and Sulfite? (Sulphur vs Sulphate vs Sulphite)

• Sulfate and Sulfite are Oxy-anions of Sulfur and Sulfur is an element.

• Sulfate and Sulfite carry negative charges, and Sulfur is neutral.

• Sulfate has 4 Oxygen atoms, and Sulfite has 3 Oxygen atoms. Sulfur is a pure element where its polyatomic structures only contain Sulfur atoms.

• Sulfate ion has the tetrahedral geometry and Sulfite has the trigonal pyramidal geometry.

• Applications of Sulfate, Sulfite, and Sulfur are different. Sulfate and Sulfite are sometimes used for common applications such as food preservation.