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Trimethylsulfonium

Trimethylsulfonium 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 Trimethylsulfonium rather than just read about it. In short: Trimethylsulfonium (systematically named trimethylsulfanium) is an organic cation with the chemical formula (CH3)3S+ (also written as C3H9S+). Compounds Several salts of trimethylsulfonium are known.

Trimethylsulfonium — main illustration
Trimethylsulfonium — illustration

Key takeaways

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

Reference excerpt

Trimethylsulfonium (systematically named trimethylsulfanium) is an organic cation with the chemical formula (CH3)3S+ (also written as C3H9S+).

Compounds

Several salts of trimethylsulfonium are known. X-ray crystallography reveals that the ion has trigonal pyramidal molecular geometry at sulfur atom, with C-S-C angles near 102° and C-S bond distance of 177 picometers. Unless the counteranion is colored, all trimethylsulfonium salts are white or colorless.

Preparation Sulfonium compounds can be synthesised by treating a suitable alkyl halide with a thioether. For example, the reaction of dimethyl sulfide with iodomethane yields trimethylsulfonium iodide:

(CH3)2S + CH3I → [(CH3)3S]+I−

Related An extra oxygen atom can bond to the sulfur atom to yield the trimethylsulfoxonium ion [(CH3)3S=O]+, where the sulfur atom is tetravalent and tetracoordinated.

Use Glyphosate herbicide is often supplied as a trimethylsulfonium salt, referred to as trimesium. When mixed with aluminium bromide, or aluminium chloride or even hydrogen bromide, trimethylsulfonium bromide forms an ionic liquid, which melts at temperatures below standard conditions.

References

See also Onium compounds

Illustrations

Trimethylsulfonium illustration
Trimethylsulfonium: Structure of (CH3)3S+ in its tetraphenylborate salt.[1]
Structure of (CH3)3S+ in its tetraphenylborate salt.[1]

Worked examples

Example 1 — a first encounter with Trimethylsulfonium

Start with the simplest possible case. Write down what Trimethylsulfonium 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 Trimethylsulfonium 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 Trimethylsulfonium 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 Trimethylsulfonium

In research
Trimethylsulfonium 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 Trimethylsulfonium 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
Trimethylsulfonium is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cations, Methyl compounds, Sulfur ions, so understanding it makes those chapters shorter.
In everyday life
Look for Trimethylsulfonium 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 Trimethylsulfonium in 20 minutes

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

Frequently asked questions

What is Trimethylsulfonium in simple terms?

Trimethylsulfonium (systematically named trimethylsulfanium) is an organic cation with the chemical formula (CH3)3S+ (also written as C3H9S+). Compounds Several salts of trimethylsulfonium are known.

Why does Trimethylsulfonium 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 Trimethylsulfonium?

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 Trimethylsulfonium.

Tags

  • Cations
  • Methyl compounds
  • Sulfur ions

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