chemistry

Sodium metatungstate

Sodium metatungstate 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 metatungstate rather than just read about it. In short: Sodium metatungstate is the inorganic compound with the formula Na6[H2W12O40], sometimes written 3Na2WO4·9WO3·H2O. It is also referred to as sodium polytungstate (SPT).

Key takeaways

Sodium metatungstate 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 metatungstate to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Sodium metatungstate from memory before moving on to harder problems.

Reference excerpt

Sodium metatungstate is the inorganic compound with the formula Na6[H2W12O40], sometimes written 3Na2WO4·9WO3·H2O. It is also referred to as sodium polytungstate (SPT). This salt has been used in the manufacture of dense aqueous solutions. Sodium metatungstate exists as white solid. The anion is the polyoxotungstate [H2W12O40]6-, which features six-coordinated tungsten(VI) centers interconnected with doubly- and triply bridging oxo ligands. Due to its very high solubility in water (max. density 3.1 g/cm3), SPT is widely used as to produce "heavy liquid" for gravity separation (sink /float analysis) and density gradient centrifugation. It has significant advantages when compared to zinc chloride solution or the toxic halogenated carbons for sink-swim analysis. Aqueous SPT is non-toxic (unlike the denser Clerici solution), non-flammable, odorless, reusable and additionally it has a low viscosity.

References

Further reading Gregory, Murray R.; Johnston, Keith A. (1987). "A nontoxic substitute for hazardous heavy liquids—aqueous sodium polytungstate (3Na2WO4.9WO3.H2O) solution (Note)". New Zealand Journal of Geology and Geophysics. 30 (3): 317. Bibcode:1987NZJGG..30..317G. doi:10.1080/00288306.1987.10552626. Bolch, C. J. S. (1997). "The use of sodium polytungstate for the separation and concentration of living dinoflagellate cysts from marine sediments". Phycologia. 36 (6): 472–478. Bibcode:1997Phyco..36..472B. doi:10.2216/i0031-8884-36-6-472.1. Six, J (1999). "Recycling of sodium polytungstate used in soil organic matter studies". Soil Biology and Biochemistry. 31 (8): 1193–1196. Bibcode:1999SBiBi..31.1193S. doi:10.1016/S0038-0717(99)00023-1. Savage, N. M. (1988). "The use of sodium polytungstate for conodont separations" (PDF). Journal of Micropalaeontology. 7 (1): 39–40. Bibcode:1988JMicP...7...39S. doi:10.1144/jm.7.1.39. S2CID 129701930.

Illustrations

Worked examples

Example 1 — a first encounter with Sodium metatungstate

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

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

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

Frequently asked questions

What is Sodium metatungstate in simple terms?

Sodium metatungstate is the inorganic compound with the formula Na6[H2W12O40], sometimes written 3Na2WO4·9WO3·H2O. It is also referred to as sodium polytungstate (SPT).

Why does Sodium metatungstate 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 metatungstate?

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 metatungstate.