science

Tetrabromonickelate

Tetrabromonickelate is a science 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 Tetrabromonickelate rather than just read about it. In short: The tetrabromonickelate anion contains a doubly-charged nickel atom (Ni2+) surrounded by four bromide ions in a tetrahedral arrangement. The formula is [NiBr4]2−.

Key takeaways

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

Reference excerpt

The tetrabromonickelate anion contains a doubly-charged nickel atom (Ni2+) surrounded by four bromide ions in a tetrahedral arrangement. The formula is [NiBr4]2−. The anion combines with cations to form a series of salts called tetrabromonickelates. Strongly-coordinating solvents will displace one or more of the bromido ligands from the complex. Solvents that can dissolve tetrabromonickelate include acetone, acetonitrile, methyl ethyl ketone, and nitromethane. In the visible absorption spectrum there is a strong absorption band termed ν3 near 710 nm which is caused by an electronic transition from 3T1(F) → 3T1(P). Another strong absorption in the near infrared called ν2 near 770 nm is due to the 3T1(F) → 3A2(F) transition.

Salts Dilithium tetrabromonickelate forms a dark blue solution in tetrahydrofuran. A mixture of lithium bromide and nickel bromide in water or methanol can transfer [NiBr4]2− ions into a cyclohexane-amine mixture. The solution formed is green. Tetraethylammonium tetrabromonickelate is blue. tetra-n-butylammonium tetrabromonickelate is purple blue in color, melting around 83°C. It is formed from nickel bromide and tetra-n-butylammonium bromide in ethyl alcohol. Tetraphenylphosphonium tetrabromonickelate(II) can be made from nickel bromide, triphenylphosphine, and bromobenzene by heating them together in a sealed tube at 250 °C. This substance is dark blue. If it is heated over 260° the color changes to green, and it melts at 273 °C. A dark blue oil, bis-(o-tolyltriethylphosphonium) tetrabromonickelate (o-CH3C6H6PEt3)2NiBr4 can be made from the reaction of o-tolyl bis-triethylphosphine, nickel bromide and o-tolyl bromide. (o-CH3OC6H6PEt3)2NiBr4 and (C6H5PEt3)2NiBr4 are made in a similar way. bis-(benzo[e]-1,3-dithiepan-2-diethylimmonium) tetrabromonickelate, abbreviated as (xdtc)2NiBr4, has dark blue crystals that melt at 166 °C. It is made from α,α'-dibromo-o-xylene and bis-(N,N-diethyldithiocarbamato)nickel(II) dissolved in 1,2-dichloroethane. bis-(tetra-n-butylphosphonium) tetrabromonickelate can form as a glass when nickel bromide is dissolved in molten tetra-n-butylphosphonium iodide. Blue 1,1,1-trimethylhydrazinium tetrabromonickelate [H2NN(CH3)3]2NiBr4 is a salt stable between 70° and 260 °C. It can be formed by heating an octahedral neutral nickel complex where the trimethylhydrazinium and bromide are all ligands on a nickel atom. The salt decomposes at room temperature to polymeric trimethylhydrazinium nickel tribromide. The salt decomposes when dissolved in polar solvents, due to solvolysis.

Related One bromine atom can be substituted by other ligands, such as triphenylphosphine, to make a dark green triphenylphosphinetribromonickelate ion. Analogous tetrahedral nickelates include tetrafluoronickelates, tetrachloronickelates, tetraiodonickelates, and tetracyanonickelates.

References

Worked examples

Example 1 — a first encounter with Tetrabromonickelate

Start with the simplest possible case. Write down what Tetrabromonickelate claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Tetrabromonickelate 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 Tetrabromonickelate 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 Tetrabromonickelate

In research: Tetrabromonickelate appears in science 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 Tetrabromonickelate 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: Tetrabromonickelate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Bromometallates, Nickel complexes, so understanding it makes those chapters shorter.
In everyday life: Look for Tetrabromonickelate 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 Tetrabromonickelate in 20 minutes

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

Frequently asked questions

What is Tetrabromonickelate in simple terms?

The tetrabromonickelate anion contains a doubly-charged nickel atom (Ni2+) surrounded by four bromide ions in a tetrahedral arrangement. The formula is [NiBr4]2−.

Why does Tetrabromonickelate matter?

Because it connects several science 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 Tetrabromonickelate?

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 Tetrabromonickelate.