Question

Which of the following does not have \(\mathrm{S}-\mathrm{S}\) linkage? (a) \(\mathrm{S}_{2} \mathrm{O}_{8}^{2-}\) (b) \(\mathrm{S}_{2} \mathrm{O}_{6}^{2-}\) (c) \(\mathrm{S}_{2} \mathrm{O}_{5}^{2-}\) (d) \(\mathrm{S}_{2} \mathrm{O}_{3}^{2-}\)

Short answer

\(\mathrm{S}_{2} \mathrm{O}_{3}^{2-}\) does not have an \(\mathrm{S}-\mathrm{S}\) linkage.

Step-by-step solution

Understand Sulfur-Sulfur Linkage

Sulfur-Sulfur linkage refers to a direct bond between two sulfur atoms, typically represented as \(\mathrm{S}-\mathrm{S}\). To solve this problem, we need to identify compounds where such a linkage is absent.

Analyze Each Compound

For each compound option, we analyze the structural possibilities to determine the presence or absence of \(\mathrm{S}-\mathrm{S}\) linkage:1. **\(\mathrm{S}_{2} \mathrm{O}_{8}^{2-}\)**: Known as peroxodisulfate, this compound features a direct \(\mathrm{S}-\mathrm{S}\) linkage because the sulfur atoms are part of two \(\mathrm{SO}_4^{2-}\) groups joined by an \(\mathrm{S}-\mathrm{S}\) bridge.2. **\(\mathrm{S}_{2} \mathrm{O}_{6}^{2-}\)**: Known as dithionate, this compound also possesses an \(\mathrm{S}-\mathrm{S}\) bond.3. **\(\mathrm{S}_{2} \mathrm{O}_{5}^{2-}\)**: Less common, but potential forms suggest an \(\mathrm{S}-\mathrm{S}\) linkage similar to dithionite.4. **\(\mathrm{S}_{2} \mathrm{O}_{3}^{2-}\)**: This compound is thiosulfate, which does not feature an \(\mathrm{S}-\mathrm{S}\) bond. Instead, it has a central sulfur atom bonded to two oxygen atoms and another sulfur.

Identify the Compound Without Sulfur-Sulfur Linkage

From the analysis, \(\mathrm{S}_{2} \mathrm{O}_{3}^{2-}\) or thiosulfate is the only compound that does not have a direct \(\mathrm{S}-\mathrm{S}\) linkage. It has a unique thiosulfate structure where one sulfur atom is bonded to an \(\mathrm{SO}_3^{2-}\) group and another sulfur atom, without forming a direct bond between the sulfur atoms themselves.

Key concepts

Sulfur-Sulfur Linkage

Sulfur-sulfur linkage is a structural feature found in some sulfur-containing compounds. This linkage, often denoted as \( \mathrm{S}-\mathrm{S} \), indicates a direct bond between two sulfur atoms. Such linkages are characteristic of many sulfur compounds, which often have unique chemical and physical properties. Understanding these linkages helps us predict the structure and reactivity of the compounds.

For instance, sulfur-sulfur linkages can be found in compounds like peroxodisulfate and dithionate, where they influence the compound's stability and reactivity. Recognizing whether a sulfur compound has this linkage can be crucial when determining its structural formula and its behavior in chemical reactions.

Analyzing which compounds feature these linkages involves looking at their molecular structure and understanding how sulfur atoms are bonded to each other and to oxygen. By examining different sulfur-oxygen compounds, we can identify those with and without sulfur-sulfur linkages, as demonstrated in the exercise.

Peroxodisulfate

Peroxodisulfate, represented by the formula \( \mathrm{S}_{2} \mathrm{O}_{8}^{2-} \), is an excellent example of a compound with sulfur-sulfur linkage. It contains two sulfate groups (\( \mathrm{SO}_{4}^{2-} \)) anchored together by a direct \( \mathrm{S}-\mathrm{S} \) bond. This linkage is crucial because it impacts the compound's properties, making it a robust oxidizing agent.

The \( \mathrm{S}-\mathrm{S} \) linkage in peroxodisulfate is akin to a bridge connecting the two sulfate ions. This structural feature allows the compound to participate in oxidation reactions usually utilized in bleaching and disinfecting processes.

Because of these properties, peroxodisulfate is often used in industrial processes and laboratory applications where strong oxidative properties are required. Recognizing the presence of a sulfur-sulfur linkage in peroxodisulfate helps to understand its reactivity and its specific uses in various chemical processes.

Dithionate

Dithionate, with the chemical formula \( \mathrm{S}_{2} \mathrm{O}_{6}^{2-} \), also features a sulfur-sulfur linkage. Similar to peroxodisulfate, this linkage involves a direct bond between the two sulfur atoms. However, dithionate is composed of two \( \mathrm{SO}_3^{2-} \) groups connected by this \( \mathrm{S}-\mathrm{S} \) bond.

The presence of a sulfur-sulfur linkage in dithionate contributes to the compound's overall stability. This stability makes dithionate useful in various chemical reactions and as an intermediate in synthesizing other sulfur-containing compounds.

Understanding the structural arrangement of dithionate helps in predicting its behavior and reactivity. Knowing that it contains a sulfur-sulfur linkage is key to comprehending its chemical properties and its potential applications in industrial and laboratory settings.

Thiosulfate

Thiosulfate, expressed as \( \mathrm{S}_{2} \mathrm{O}_{3}^{2-} \), is unique among the discussed compounds as it does not have a sulfur-sulfur linkage. Instead, thiosulfate consists of a central sulfur atom bound to two oxygen atoms and one other sulfur atom. This different structure gives thiosulfate its distinct chemical properties.

Since it lacks the \( \mathrm{S}-\mathrm{S} \) bond, thiosulfate shows a different reactivity profile. It's commonly known for its ability to neutralize bleach and its use in photographic processing and gold extraction.

Recognizing that thiosulfate doesn't have a sulfur-sulfur linkage is important when considering its role in various chemical processes. Its unique structure allows it to participate in reactions that are not possible for other sulfur compounds with \( \mathrm{S}-\mathrm{S} \) linkages.