chemistry

Selenosulfide

Selenosulfide is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Selenosulfide rather than just read about it. In short: In chemistry, a selenosulfide refers to distinct classes of inorganic and organic compounds containing sulfur and selenium. The organic derivatives contain Se-S bonds, whereas the inorganic derivatives are more variable.

Key takeaways

Selenosulfide belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Selenosulfide to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Selenosulfide from memory before moving on to harder problems.

Reference excerpt

In chemistry, a selenosulfide refers to distinct classes of inorganic and organic compounds containing sulfur and selenium. The organic derivatives contain Se-S bonds, whereas the inorganic derivatives are more variable.

Organic selenosulfides These species are classified as both organosulfur and organoselenium compounds. They are hybrids of organic disulfides and organic diselenides.

Preparation, structure, and reactivity Selenosulfides have been prepared by the reaction of selenyl halides with thiols:

RSeCl + R'SH → RSeSR' + HCl The equilibrium between diselenides and disulfides lies on the left:

RSeSeR + R'SSR' ↽ − ⇀ {\displaystyle {\ce {<<=>}}} 2 RSeSR' Because of the facility of this equilibrium, many of the best characterized examples of selenosulfides are cyclic, whereby S-Se bonds are stabilized intramolecularly. One example is the 1,8-selenosulfide of naphthalene. The selenium-sulfur bond length is about 220 picometers, the average of a typical S-S and Se-Se bond.

Occurrence Selenosulfide groups can be found in almost all living organisms as part of various peroxidase enzymes, such as glutathione peroxidase and thioredoxin reductase. They are formed by the oxidative coupling of selenocysteine and cysteine residues. This reaction is powered by the decomposition of cellular peroxides, which can be highly damaging and a source of oxidative stress. Selenocysteine has a lower reduction potential than cysteine, making it very suitable for proteins that are involved in antioxidant activity. Selenosulfides have been identified in some species of Allium and in roasted coffee. The mammalian version of the protein thioredoxin reductase contains a selenocysteine residue which forms a thioselenide (analogous to a disulfide) upon oxidation.

Inorganic selenosulfides

Some inorganic selenide sulfide compounds are also known. Simplest is the material selenium sulfide, which has medicinal properties. It adopt the diverse structures of elemental sulfur but with some S atoms replaced by Se. Other inorganic selenide sulfide compounds occur as minerals and as pigments. One example is antimony selenosulfide. The pigment cadmium red consists of cadmium sulfoselenide. It is a solid solution of cadmium sulfide, which is yellow, and cadmium selenide, which is dark brown. It is used as an artist's pigment. Unlike the organic selenosulfides and unlike selenide sulfide itself, no S-Se bond exists in CdS1−xSex or in Sb2S3−xSex.

References

Illustrations

Worked examples

Example 1 — a first encounter with Selenosulfide

Start with the simplest possible case. Write down what Selenosulfide claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Selenosulfide before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Selenosulfide ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Selenosulfide

In research: Selenosulfide appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Selenosulfide in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Selenosulfide is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cadmium compounds, Chalcogenides, Mixed anion compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Selenosulfide outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Selenosulfide in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Selenosulfide means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Selenosulfide out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Selenosulfide in simple terms?

Why does Selenosulfide matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Selenosulfide?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Selenosulfide.