The key difference between sulfur, sulfate and sulfite is that Sulfur is an element whereas Sulfate and Sulfite are Oxy-anions of Sulfur.
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?
Sulfur is a non-metallic element. The chemical symbol of this element is S. It is present in numerous compounds and in various forms. Atomic number is 16. In the pure form, Sulfur can have many physical forms. Therefore, we call it an allotropic element.
The most common is the crystalline yellow color solid which is very brittle. This element is extremely reactive and has many applications. It is useful in the production of gunpowder, insecticides and prescription drugs etc.
What is Sulfate?
Sulfate is an Oxy-anion of Sulfur (An oxy-anion is Oxygen containing negative ion). Even if you are not familiar with this ion you must know Sulfuric acid. Sulfuric acid consists of two H+ ions and one sulfate ion. The empirical formula of this ion is SO42- . It is a polyatomic anion. In this ion, Sulfur atom is the central atom and four Oxygen atoms are covalently bound to this central atom.
Two Oxygen atoms bind through double bonds and the other two are single bound. The single bound Oxygen atoms originally contain a Hydrogen atom in each of them. When this ion forms, it releases H+ and carry negative charges. The geometry of the ion is tetrahedral where Oxygen atoms are in the four corners of the tetrahedron.
What is Sulfite?
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. This ion has three Oxygen atoms doubly bonded to the central Sulfur atom. When the H+ ions are present, Sulfite becomes Sulfurous acid.
This acid is relatively weaker than the Sulfuric acid. The geometry of this anion is trigonal pyramidal. The Oxygen atoms are at the three edges, and a lone pair of electrons is on the top. The empirical formula of this ion is SO32-.
What is the Difference Between Sulfur, Sulfate and Sulfite?
Sulfur is a non-metallic element having the atomic number 16.
Sulfate is an Oxy-anion of Sulfur having the chemical formula SO42-
Sulfite is another Oxy-anion of Sulfurhaving the chemical formulaSO32-.
The atomic mass of sulfur is 32.065 amu.
The molar mass of sulfate is96.06 g/mol.
The molar mass of sulfite is 80.06 g/mol.
Sulfur is neutral
Sulfate carries a negative charge.
Sulfite carries a negative charge.
Sulfur is a pure element where its polyatomic structures only contain Sulfur atoms.
Sulfate has 4 Oxygen atoms
Sulfite has 3 Oxygen atoms
Polyatomic structures of sulfur have different geometries.
Sulfate ion has the tetrahedral geometry
Sulfite has the trigonal pyramidal geometry.
Summary – Sulfur, Sulfate vs Sulfite
Sulfur is a nonmetallic element that involves the formation of different compounds. Sulfate and sulfite are anions formed from the combination of sulfur and oxygen. The difference between sulfur, sulfate, and sulfite is that Sulfur is an element whereas Sulfate and Sulfite are Oxy-anions of Sulfur.
1. Pappas, Stephanie. “Facts About Sulfur.” LiveScience, Purch, 28 Sept. 2017. Available here
2. “Sulfate Ion.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine. Available here
3. “Sulfite.” Wikipedia, Wikimedia Foundation, 24 Apr. 2018. Available here
1.’Sulfur-sample’By Ben Mills – Own work, (Public Domain) via Commons Wikimedia
2.’Sulfate’By Leyo – Own work, (Public Domain) via Commons Wikimedia
3.’Sulfite-ion-2D-dimensions’ (Public Domain) via Commons Wikimedia