isologue

Very Low (Technical/Specialist)
UK/ˈaɪsəlɒɡ/US/ˈaɪsəˌlɔːɡ/

Formal, Technical, Scientific

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Definition

Meaning

A chemical compound that is structurally similar to another, differing only by the replacement of an atom or group with another of similar valency or properties.

In a broader scientific context, any entity (e.g., a molecule, gene, or structure) that is analogous to another in form or function, often within a homologous series.

Linguistics

Semantic Notes

Primarily used in chemistry and biochemistry. The term denotes a specific type of structural analogy, not just general similarity. It implies a systematic, predictable variation within a series of related compounds.

Dialectal Variation

British vs American Usage

Differences

No significant differences in meaning or usage. Spelling is identical.

Connotations

None beyond its technical definition.

Frequency

Equally rare and specialised in both varieties.

Vocabulary

Collocations

strong
chemical isologuestructural isologueseries of isologues
medium
form an isologuebehave as an isologueisologue of
weak
synthetic isologuebiological isologueclose isologue

Grammar

Valency Patterns

X is an isologue of YThe isologues of benzeneTo form isologues with

Vocabulary

Synonyms

Strong

homolog (in specific series)congener (in chemistry)

Neutral

structural analogcongener

Weak

analoguerelated compound

Vocabulary

Antonyms

heterologueunrelated compoundstructurally distinct entity

Usage

Context Usage

Business

Not used.

Academic

Used in specialised chemistry and biochemistry papers to describe compound relationships.

Everyday

Never used.

Technical

Core term in specific sub-fields of chemistry for precise classification of molecular structures.

Examples

By Part of Speech

adjective

British English

  • The isologue series showed predictable changes in boiling point.
  • They studied the isologue relationships within the new polymer family.

American English

  • The isologue compounds were tested for reactivity.
  • An isologue replacement was made in the synthetic pathway.

Examples

By CEFR Level

B2
  • Researchers identified a new isologue in the laboratory.
  • The properties of an isologue can often be predicted from its relatives.
C1
  • The team synthesised the sulphur isologue of the original oxygen-based compound to study its metabolic pathway.
  • By examining a complete series of isologues, they were able to deduce the key structural determinant for receptor binding.

Learning

Memory Aids

Mnemonic

Think 'ISO' (same) + 'LOGUE' (as in analogue, meaning a similar thing). An isologue is the 'same kind of talk' or story in chemical structure.

Conceptual Metaphor

CHEMICAL COMPOUNDS ARE WORDS IN A LANGUAGE (where isologues are synonyms or words with the same grammatical structure).

Watch out

Common Pitfalls

Translation Traps (for Russian speakers)

  • Do not confuse with 'изолог' (a term from mathematics/geometry referring to a line of equal values). The chemical term is highly specific.
  • Avoid direct translation as 'изолог' in a chemical context without verifying the intended mathematical vs. chemical meaning.

Common Mistakes

  • Using 'isologue' to mean any similar thing outside of precise chemical/structural series.
  • Confusing it with 'isotope' (same element, different neutrons) or 'isomer' (same formula, different arrangement).

Practice

Quiz

Fill in the gap
In organic chemistry, a thiophene is often considered the sulphur of furan.
Multiple Choice

In which field is the term 'isologue' primarily used?

FAQ

Frequently Asked Questions

No, it is a highly specialised technical term used almost exclusively in chemistry and related sciences.

An isomer has the same molecular formula but a different arrangement of atoms. An isologue has a similar structure but with a specific atom or group replaced by another of similar valency (e.g., oxygen replaced by sulphur).

No, standard usage is only as a noun or adjective (e.g., 'isologue compound').

No, it is only relevant for learners specializing in advanced chemistry or biochemistry.