chemistry

Sodium monothiophosphate

Sodium monothiophosphate 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 monothiophosphate rather than just read about it. In short: Sodium monothiophosphate, or sodium phosphorothioate, is an inorganic compound with the chemical formula Na3PO3S. It is a sodium salt of monothiophosphoric acid (H3PO3S).

Key takeaways

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

Reference excerpt

Sodium monothiophosphate, or sodium phosphorothioate, is an inorganic compound with the chemical formula Na3PO3S. It is a sodium salt of monothiophosphoric acid (H3PO3S). Sodium monothiophosphate forms hydrates Na3PO3S·xH2O. The anhydrous form and all hydrates are white solids. The anhydrous salt (x = 0) (Na3PO3S) decomposes without melting at 120-125 °C. More common is the dodecahydrate (Na3PO3S·12H2O). A nonahydrate is also known (Na3PO3S·9H2O). Related salts are the sodium dithiophosphate undecahydrate Na3PO2S2·11H2O, sodium trithiophosphate undecahydrate Na3POS3·11H2O, and sodium tetrathiophosphate octahydrate Na3PS4·8H2O.

Preparation Sodium monothiophosphate is prepared by the base hydrolysis of thiophosphoryl chloride using aqueous sodium hydroxide:

PSCl3 + 6 NaOH + 9 H2O → Na3PO3S·12H2O + 3 NaCl This reaction affords the dodecahydrate, which is easily dehydrated. Partial dehydration over 6.5 M H2SO4 gives the nonahydrate. Under flowing N2, the anhydrous salt is formed. Sodium monothiophosphate decomposes at neutral pH. Silicone grease catalyses the hydrolysis of the monothiophosphate ion PO3S3−, so it is recommended that it is not used in the glass joints. In the anhydrous salt, the P-S bond is 211 pm and the three equivalent P-O bonds are short at 151 pm. These disparate values suggest that the P-S bond is single.

References

Illustrations

Worked examples

Example 1 — a first encounter with Sodium monothiophosphate

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

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

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

Frequently asked questions

What is Sodium monothiophosphate in simple terms?

Sodium monothiophosphate, or sodium phosphorothioate, is an inorganic compound with the chemical formula Na3PO3S. It is a sodium salt of monothiophosphoric acid (H3PO3S).

Why does Sodium monothiophosphate 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 monothiophosphate?

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 monothiophosphate.