ArticleslgStudy

chemistry

Metallaborane

Metallaborane 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 Metallaborane rather than just read about it. In short: In chemistry, a metalloborane is a compound that contains one or more metal atoms and one or more boron hydride unit. These compounds are related conceptually and often synthetically to the boron-hydride clusters by replacement of BHn units – sometimes called vertices – with metal-containing fragments.

Metallaborane — main illustration
Metallaborane — illustration

Key takeaways

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

Reference excerpt

In chemistry, a metalloborane is a compound that contains one or more metal atoms and one or more boron hydride unit. These compounds are related conceptually and often synthetically to the boron-hydride clusters by replacement of BHn units – sometimes called vertices – with metal-containing fragments. Often these metal fragments are derived from metal carbonyls or cyclopentadienyl complexes. Their structures can often be rationalized by polyhedral skeletal electron pair theory. The inventory of these compounds is large, and their structures can be quite complicated.

Examples

Two simple examples are B4H8Fe(CO)3 and B4H8Co(C5H5). The MB4 cores (M = Fe or Co) of these two compounds adopt structures expected for nido 5-vertex clusters. The iron compound is produced by reaction of diiron nonacarbonyl with pentaborane. B4H8Fe(CO)3 and cyclobutadieneiron tricarbonyl have similar structures.

Metallacarboranes

Even greater in scope than metalloboranes are metallacarboranes. These cages have carbon vertices, often CH, in addition to BH and M vertices. A well-developed class of metallacarboranes are prepared from dicarbollides, anions of the formula [C2B9H11]2−. These anions function as ligands for a variety of metals, often forming sandwich complexes. Some metalloboranes are derived by the metalation of neutral carboranes. Illustrative are the six-and seven-vertex cages prepared from closo-C2B3H5. Reaction of this carborane with iron carbonyl sources gives closo Fe- and Fe2-containing products, according to these idealized equations:

C2B3H5 + Fe2(CO)9 → C2B3H5Fe(CO)3 + Fe(CO)5 + CO C2B3H5Fe(CO)3 + Fe2(CO)9 → C2B3H5(Fe(CO)3)2 + Fe(CO)5 + CO A further example of insertion into a closo carborane is the synthesis of the yellow-orange closo-1,2,3-(CO)3FeC2B4H6:

closo-C2B4H8 + Fe2(CO)9 → closo-(CO)3FeC2B4H6 + Fe(CO)5 + CO A closely related reaction involves the capping of an anionic nido carborane C2B4H−7

closo-C2B4H8 + NaH → Na(nido-B4H7) + H2 Na(nido-B4H7) + CoCl2 + NaC5H5 → closo-(C5H5)CoB4H6 + 2 NaCl + … The last reaction is worked up with acid and air.

See also Metal complexes of borohydride, coordination complexes containing the borohydride (BH−4) ligand.

References

Illustrations

Metallaborane: Structure of .mw-parser-output .template-chem2-su{display:inline-block;font-size:80%;line-height:1;vertical-align:-0.35em}.mw-parser-output .template-chem2-su>span{display:block;text-align:left}.mw-parser-output sub.template-chem2-sub{font-size:80%;vertical-align:-0.35em}.mw-parser-output sup.template-chem2-sup{font-size:80%;vertical-align:0.65em}(C5(CH3)5)FeHCo(CO)3B4H7.[1] Color code: yellow = B, blue = Fe & Co, red = O, gray = C.
Structure of .mw-parser-output .template-chem2-su{display:inline-block;font-size:80%;line-height:1;vertical-align:-0.35em}.mw-parser-output .template-chem2-su>span{display:block;text-align:left}.mw-parser-output sub.template-chem2-sub{font-size:80%;vertical-align:-0.35em}.mw-parser-output sup.template-chem2-sup{font-size:80%;vertical-align:0.65em}(C5(CH3)5)FeHCo(CO)3B4H7.[1] Color code: yellow = B, blue = Fe & Co, red = O, gray = C.
Metallaborane: Chemical structure of B4H8Fe(CO)3. As is customary for boron hydrides, the lines drawn between B and H do not represent 2-center, 2-electron bonds.
Chemical structure of B4H8Fe(CO)3. As is customary for boron hydrides, the lines drawn between B and H do not represent 2-center, 2-electron bonds.
Metallaborane: Structure of (Me4N+)2[Fe(C2B9H11)2]2−, showing only one Me4N+.[4]
Structure of (Me4N+)2[Fe(C2B9H11)2]2−, showing only one Me4N+.[4]

Worked examples

Example 1 — a first encounter with Metallaborane

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

In research
Metallaborane 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 Metallaborane 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
Metallaborane is common in secondary-school and first-year university syllabi. It links to neighbouring topics Boranes, Cluster chemistry, so understanding it makes those chapters shorter.
In everyday life
Look for Metallaborane 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.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Metallaborane in 20 minutes

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

Frequently asked questions

What is Metallaborane in simple terms?

In chemistry, a metalloborane is a compound that contains one or more metal atoms and one or more boron hydride unit. These compounds are related conceptually and often synthetically to the boron-hydride clusters by replacement of BHn units – sometimes called vertices – with metal-containing fragme…

Why does Metallaborane 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 Metallaborane?

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 Metallaborane.

Tags

  • Boranes
  • Cluster chemistry

Keep exploring