thiosulfate: meaning, definition, pronunciation and examples

C2
UK/ˌθaɪə(ʊ)ˈsʌlfeɪt/US/ˌθaɪoʊˈsʌlfeɪt/

Technical/Scientific

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Quick answer

What does “thiosulfate” mean?

A chemical compound containing the S₂O₃²⁻ anion, where a sulfur atom replaces an oxygen atom in a sulfate ion.

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Pronunciation

Definition

Meaning and Definition

A chemical compound containing the S₂O₃²⁻ anion, where a sulfur atom replaces an oxygen atom in a sulfate ion.

In chemistry, a salt or ester of thiosulfuric acid. In specific applications (e.g., photography, medicine), it refers to sodium thiosulfate (hypo) used as a fixing agent or an antidote.

Dialectal Variation

British vs American Usage

Differences

No significant spelling or usage differences. Both variants use 'thiosulfate', though British publications may occasionally use 'thiosulphate' (see note below).

Connotations

Identical technical meaning in both dialects.

Frequency

Extremely low frequency in general discourse, confined to specialised fields.

Grammar

How to Use “thiosulfate” in a Sentence

[Substance] is treated with thiosulfateThiosulfate reacts with [iodine/cyanide]The thiosulfate concentration was determined by titration.

Vocabulary

Collocations

strong
sodium thiosulfateammonium thiosulfatethiosulfate ionthiosulfate solution
medium
analyse thiosulfateconcentration of thiosulfatereacts with thiosulfateadd thiosulfate
weak
aqueous thiosulfateexcess thiosulfatethiosulfate saltsthiosulfate chemistry

Examples

Examples of “thiosulfate” in a Sentence

noun

British English

  • The thiosulphate was added dropwise to quench the reaction.
  • Old photographic fixer contains used-up thiosulphate.

American English

  • The thiosulfate concentration is critical for the titration endpoint.
  • Sodium thiosulfate is the preferred antidote in this kit.

Usage

Meaning in Context

Business

Rare; only in specific industrial chemical supply or photographic equipment contexts.

Academic

Common in chemistry, chemical engineering, pharmacology, and environmental science textbooks and papers.

Everyday

Virtually never used.

Technical

Standard term in analytical chemistry, water treatment, photography (fixing baths), and medical toxicology (cyanide antidote).

Vocabulary

Synonyms of “thiosulfate”

Neutral

hypo (for sodium thiosulfate in photography)antichlor (in some industrial contexts)

Weak

sulphite (incorrect but common learner error)

Vocabulary

Antonyms of “thiosulfate”

Watch out

Common Mistakes When Using “thiosulfate”

  • Misspelling as 'thiosulphate' (archaic/UK variant) in American contexts.
  • Confusing with 'sulfate' or 'sulfite'.
  • Incorrect plural: 'thiosulfates' is correct.
  • Mispronouncing 'thio-' as /ˈθiːoʊ/ instead of /ˌθaɪoʊ/.

FAQ

Frequently Asked Questions

Both are correct, but 'thiosulfate' is the standard IUPAC and American English spelling. 'Thiosulphate' is an older British variant, now less common even in UK scientific publishing.

'Hypo' is a traditional, informal name for sodium thiosulfate (Na₂S₂O₃), specifically in the context of photography.

Sodium thiosulfate is generally low in toxicity and is even used medically as an antidote. However, as with all chemicals, appropriate safety handling for its specific form and concentration is required.

In chemical nomenclature, the prefix 'thio-' indicates that a sulfur atom replaces an oxygen atom in the parent compound (e.g., sulfate SO₄²⁻ → thiosulfate S₂O₃²⁻).

A chemical compound containing the S₂O₃²⁻ anion, where a sulfur atom replaces an oxygen atom in a sulfate ion.

Thiosulfate is usually technical/scientific in register.

Thiosulfate: in British English it is pronounced /ˌθaɪə(ʊ)ˈsʌlfeɪt/, and in American English it is pronounced /ˌθaɪoʊˈsʌlfeɪt/. Tap the audio buttons above to hear it.

Learning

Memory Aids

Mnemonic

Think: 'THIO' = SULFUR (like 'thiourea'). So, thio-SULFATE = a sulfate with sulfur swapped in.

Conceptual Metaphor

A SUBSTITUTE or STAND-IN (sulfur stands in for oxygen in the sulfate structure).

Practice

Quiz

Fill in the gap
In traditional film development, the fixing bath contains sodium to dissolve unexposed silver halides.
Multiple Choice

What is the primary role of thiosulfate in iodometric titration?