The key difference between sulfonate and sulfate is that sulfonate is an anion that forms from sulfonic acid, whereas sulfate is an anion that forms from sulfuric acid.
Although the terms sulfonate and sulfate sound similar, they are completely different anions. If we look at their chemical structure, sulfonate has an R group, which is an organic group, while sulfate has no R groups.
CONTENTS
1. Overview and Key Difference
2. What is Sulfonate
3. What is Sulfate
4. Side by Side Comparison – Sulfonate vs Sulfate in Tabular Form
6. Summary
What is Sulfonate?
Sulfonate is an anion which has the chemical formula R-SO3−. Here, the R group is an organic group. And, this anion originates from the sulfonic acid. Generally, these anions are stable in water and are colourless in aqueous solution. Moreover, these anions are non-oxidizing. The chemical structure is as follows:
Sulfonic acids are strong acids. Since the sulfonate is the conjugate base of sulfonic acid, the sulfonate is a weak base. The oxidation state of the sulfur atom in this anion is +5, and the overall charge is -1. Similar to the sulfate anion, this anion also has two S=O bonds but has R-S bond and S-O bond as the single bonds (sulfate anion has two SO single bonds).
What is Sulfate?
Sulfate is an anion having the chemical formula SO4−2. It originates from the sulfuric acid. And, this anion has four oxygen atoms attached to the central sulfur atom, and the anion has a tetrahedral geometry. The sulfur atom has a +6 oxidation state. There are two oxygen atoms with -1 charge.
Figure 02: Structure of Sulfate Anion
We can produce this anion using two major methods:
- Treating a metal or a metal oxide with sulfuric acid
- Oxidation metal sulfides into sulfites
With few exceptions such as calcium sulfate and strontium sulfate, all other sulfate compounds are known to be water-soluble. Furthermore, this anion can serve as a ligand in coordination compounds by attaching with one oxygen atom (monodentate ligand) or two (bidentate ligand).
What is the Difference Between Sulfonate and Sulfate?
Sulfonate is an anion which has the chemical formula R-SO3− while Sulfate is an anion having the chemical formula SO4−2. The key difference between sulfonate and sulfate is that sulfonate is an anion that forms from the sulfonic acid, whereas sulfate is an anion that forms from the sulfuric acid.
Further, the oxidation state of the sulfur atom in sulfonate is +5, and in sulfate, it is +6. Apart from that, the overall charge of sulfonate anion is -1, and in sulfate anion, it is -2. So, this is also a difference between sulfonate and sulfate.
Summary – Sulfonate vs Sulfate
Sulfonate is an anion which has the chemical formula R-SO3− while Sulfate is an anion having the chemical formula SO4−2. The key difference between sulfonate and sulfate is that sulfonate is an anion that forms from the sulfonic acid, whereas sulfate is an anion that forms from the sulfuric acid.
Reference:
1. Deziel, Chris. “What Is Sulfate?” Sciencing, 2 Mar. 2019, Available here.
Image Courtesy:
1. “SulfonateTet” By Smokefoot – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Sulfate-ion-2D-dimensions” By Benjah-bmm27 – Own work (Public Domain) via Commons Wikimedia