chemistry

Sodium decavanadate

Sodium decavanadate 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 decavanadate rather than just read about it. In short: Sodium decavanadate describes any member of the family of inorganic compounds with the formula Na6[V10O28]·nH2O. These are sodium salts of the orange-colored decavanadate anion [V10O28]6−.

Key takeaways

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

Reference excerpt

Sodium decavanadate describes any member of the family of inorganic compounds with the formula Na6[V10O28]·nH2O. These are sodium salts of the orange-colored decavanadate anion [V10O28]6−. Numerous other decavanadate salts have been isolated and studied since 1956 when it was first characterized.

Acid-base properties Aqueous vanadate (V) compounds undergo various self-condensation reactions. Depending on pH, major vanadate anions in solution include VO2(H2O)+4, VO3−4, V2O3−7, V3O3−9, V4O4−12, and V10O6−28. The anions often reversibly protonate. Decavanadate forms according to this equilibrium:

H3V10O3−28 ⇌ H2V10O4−28 + H+ H2V10O4−28 ⇌ HV10O5−28 + H+ HV10O5−28(aq) ⇌ V10O6−28 + H+ The structure of the various protonation states of the decavanadate ion has been examined by 51V NMR spectroscopy. Each species gives three signals; with slightly varying chemical shifts around −425, −506, and −523 ppm relative to vanadium oxytrichloride; suggesting that rapid proton exchange occurs resulting in equally symmetric species. The three protonations of decavanadate have been shown to occur at the bridging oxygen centers, indicated as B and C in figure 1. Decavanadate is most stable in the pH 4–7 region. Solutions of vanadate turn bright orange at pH 6.5, indicating the presence of decavanadate. Other vanadates are colorless. Below pH 2.0, brown V2O5 precipitates as the hydrate.

V10O6−28 + 6 H+ + 12 H2 ⇌ 5 V2O5

Structure

The decavanadate ion consists of ten fused VO6 octahedra and has D2h symmetry. The structure of Na6[V10O28]·18H2O has been confirmed with X-ray crystallography. The decavanadate anions contains three sets of equivalent V atoms (see fig. 1). These include two central VO6 octahedra (Vc) and four each peripheral tetragonal-pyramidal VO5 groups (Va and Vb). There are seven unique groups of oxygen atoms (labeled A through G). Two of these (A) bridge to six V centers, four (B) bridge three V centers, fourteen of these (C, D and E) span edges between pairs of V centers, and eight (F and G) are peripheral. The oxidation state of vanadium in decavanadate is +5.

Preparation The preparation of decavanadate is achieved by acidifying an aqueous solution of orthovanadate (VO3−4:

10 Na3[VO4] + 24 HOAc → Na6[V10O28] + 12 H2O + 24 NaOAc The formation of decavanadate is optimized by maintaining a pH range of 4–7. Typical side products include metavanadate, VO−3, and hexavanadate, V6O2−16, ions.

Potential uses Decavanadate has been found to inhibit phosphoglycerate mutase, an enzyme which catalyzes step 8 of glycolysis. In addition, decavandate was found to have modest inhibition of Leishmania tarentolae viability, suggesting that decavandate may have a potential use as a topical inhibitor of protozoan parasites.

Related decavanadates Many decavanadate salts have been characterized. NH+4, Ca2+, Ba2+, Sr2+, and group I decavanadate salts are prepared by the acid–base reaction between V2O5 and the oxide, hydroxide, carbonate, or hydrogen carbonate of the desired positive ion.

6 NH3 + 5 V2O5 + 3 H2O ⇌ (NH4)6[V10O28] Other decavanadates:

(NH4)6[V10O28]·6H2O K6[V10O28]·9H2O K6[V10O28]·10H2O Ca3[V10O28]·16H2O K2Mg2[V10O28]·16H2O K2Zn2[V10O28]·16H2O Cs2Mg2[V10O28]·16H2O Cs4Na2[V10O28]·10H2O K4Na2[V10O28]·16H2O Sr3[V10O28]·22H2O Ba3[V10O28]·19H2O [(C6H5)4P]H3V10O28·4CH3CN Ag6[V10O28]·4H2O Naturally occurring decavanadates include:

Ca3V10O28·17H2O (Pascoite) Ca2Mg(V10O28)·16H2O (Magnesiopascoite) Na4Mg(V10O28)·24H2O (Huemulite)

References

Illustrations

Sodium decavanadate: Figure 1: structure of decavanadate ion with equivalent V and O atoms indicated — Figure 1: structure of decavanadate ion with equivalent V and O atoms indicated

Worked examples

Example 1 — a first encounter with Sodium decavanadate

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

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

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Frequently asked questions

What is Sodium decavanadate in simple terms?

Sodium decavanadate describes any member of the family of inorganic compounds with the formula Na6[V10O28]·nH2O. These are sodium salts of the orange-colored decavanadate anion [V10O28]6−.

Why does Sodium decavanadate 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 decavanadate?

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 decavanadate.