chemistry

Sodium tetraphenylborate

Sodium tetraphenylborate 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 Sodium tetraphenylborate rather than just read about it. In short: Sodium tetraphenylborate is the organic compound with the formula NaB(C6H5)4. It is a salt, wherein the anion consists of four phenyl rings bonded to boron.

Key takeaways

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

Reference excerpt

Sodium tetraphenylborate is the organic compound with the formula NaB(C6H5)4. It is a salt, wherein the anion consists of four phenyl rings bonded to boron. This white crystalline solid is used to prepare other tetraphenylborate salts, which are often highly soluble in organic solvents. The compound is used in inorganic and organometallic chemistry as a precipitating agent for potassium, ammonium, rubidium, and caesium ions, and some organic nitrogen compounds.

Synthesis and structure Sodium tetraphenylborate is synthesized by the reaction between sodium tetrafluoroborate and phenylmagnesium bromide:

NaBF4 + 4 PhMgBr → 2 MgBr2 + 2 MgF2 + NaBPh4 (where Ph = phenyl) A related synthesis involves the use of phenylsodium in place of the Grignard reagent. Unlike smaller counteranions, such as nitrate and the halides, tetraphenylborate confers lipophilicity to its salts. Many analogous tetraarylborates have been synthesized, containing both electron-rich and electron-deficient aryl groups. The anhydrous salt adopts a polymeric structure in the solid state consisting of Na+-phenyl interactions. As such the salt could be classified as an organosodium compound.

Use in chemical synthesis

Preparation of N-acylammonium salts Addition of sodium tetraphenylborate to a solution of a tertiary amine and an acid chloride in acetonitrile gives the acylonium salt by precipitating NaCl from the reaction mixture. This method has a broad scope:

RC(O)Cl + R'3N + NaB(C6H5)4 → [RC(O)NR'3][B(C6H5)4] + NaCl Sodium tetraphenylborate is also employed as a phenyl donor in palladium-catalyzed cross-coupling reactions involving vinyl and aryl triflates to give arylalkenes and biaryl compounds in good yields and under mild conditions, respectively.

Use in coordination chemistry Tetraphenylborates are often studied in organometallic chemistry because of their good solubility in nonpolar solvents and their crystallinity. For example, the homoleptic trimethylphosphite complexes {M[P(OCH3)3]5}2+ (Ni, Pd, and Pt) have been prepared as their tetraphenylborate salts. Similarly, sodium tetraphenylborate has been used to isolate complexes containing dinitrogen ligands. In the reaction below, sodium tetraphenylborate allows N2 to displace the chloride ligand, which is removed from solution as a precipitate of sodium chloride:

FeHCl(diphosphine)2 + NaB(C6H5)4 + N2 → [FeH(N2)(diphosphine)2]B(C6H5)4 + NaCl The use of tetraphenylborate is limited to non-acidic cations. With strong acids, the anion undergoes protonolysis to give triphenylborane and benzene:

H+ + B(C6H5)4− → B(C6H5)3 + C6H6

Related tetraorganoborates Weakly coordinating anions often are based on tetraarylborates, with electronegative substituents. Examples include B(C6F5)4− and Brookhart's acid containing the tetrakis[3,5-bis(trifluoromethyl)phenyl]borate anion.

References

Illustrations

Worked examples

Example 1 — a first encounter with Sodium tetraphenylborate

Start with the simplest possible case. Write down what Sodium tetraphenylborate 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 Sodium tetraphenylborate 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 Sodium tetraphenylborate 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 Sodium tetraphenylborate

In research: Sodium tetraphenylborate 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 Sodium tetraphenylborate 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: Sodium tetraphenylborate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Sodium compounds, Tetraphenylborates, so understanding it makes those chapters shorter.
In everyday life: Look for Sodium tetraphenylborate 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 Sodium tetraphenylborate in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sodium tetraphenylborate 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.
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Frequently asked questions

What is Sodium tetraphenylborate in simple terms?

Sodium tetraphenylborate is the organic compound with the formula NaB(C6H5)4. It is a salt, wherein the anion consists of four phenyl rings bonded to boron.

Why does Sodium tetraphenylborate 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 Sodium tetraphenylborate?

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 Sodium tetraphenylborate.