chemistry

Xylyl bromide

Xylyl bromide 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 Xylyl bromide rather than just read about it. In short: Xylyl-bromide, also known as methylbenzyl bromide or T-stoff ('substance-T'), is any member or a mixture of organic chemical compounds with the molecular formula C6H4(CH3)(CH2Br). The mixture was formerly used as a tear gas and has an odor reminiscent of lilac.

Key takeaways

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

Reference excerpt

Xylyl-bromide, also known as methylbenzyl bromide or T-stoff ('substance-T'), is any member or a mixture of organic chemical compounds with the molecular formula C6H4(CH3)(CH2Br). The mixture was formerly used as a tear gas and has an odor reminiscent of lilac. All members and the mixture are colourless liquids, although commercial or older samples appear yellowish.

Use as a weapon Xylyl bromide is an irritant and lachrymatory agent. It has been incorporated in chemical weapons since the early months of World War I. Some commentators say the first use was in August 1914, when the French attacked German soldiers with tear gas grenades, but the agent used in that incident was more likely to be ethyl bromoacetate, which the French had tested before the war. The first extensive use of xylyl bromide was the firing by German forces of 18,000 "T-shells" at Russian positions in the Battle of Bolimów in January 1915. The shells were modified 15 cm (6 inch) artillery shells containing an explosive charge and c. 3 kg (7 lb) xylyl bromide. The attack was a complete failure because the winter weather was too cold to permit an effective aerosol, and the agent was either blown back towards the German lines, fell harmlessly to the ground, or was insufficiently concentrated to cause damage. A similar attack at Nieuwpoort in March 1915 was also unsuccessful. Nevertheless, because of its ease of manufacture xylyl bromide was widely used in World War I, in particular as a component of the Germans' Weisskreuz (white cross) mixture.

Structural isomers Three isomers, collectively referred to by CAS registry number 35884-77-6, are:

CAS RN 89-92-9: o-xylyl bromide (2-methylbenzyl bromide, systematic name 1-(bromomethyl)-2-methylbenzene) CAS RN 620-13-3: m-xylyl bromide (3-methylbenzyl bromide, systematic name 1-(bromomethyl)-3-methylbenzene) CAS RN 104-81-4: p-xylyl bromide (4-methylbenzyl bromide, systematic name 1-(bromomethyl)-4-methylbenzene) In the absence of clarification, the name "xylyl bromide" may refer to any one of these isomers or a mixture of all three.

See also Chemical weapons in World War I Tetrabromo-o-xylene

References

External links Hazardous Substances Data Bank (HSDB) record

Worked examples

Example 1 — a first encounter with Xylyl bromide

Start with the simplest possible case. Write down what Xylyl bromide 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 Xylyl bromide 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 Xylyl bromide 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 Xylyl bromide

In research: Xylyl bromide 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 Xylyl bromide 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: Xylyl bromide is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chemical weapons in World War I, Lachrymatory agents, Organobromides, so understanding it makes those chapters shorter.
In everyday life: Look for Xylyl bromide 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 Xylyl bromide in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Xylyl bromide 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 Xylyl bromide out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Xylyl bromide in simple terms?

Why does Xylyl bromide 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 Xylyl bromide?

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 Xylyl bromide.