double salt
Very Low (Technical/Specialist)Technical/Scientific
Definition
Meaning
A chemical compound formed by the combination of two different salts which crystallize together in a definite ratio but ionize as separate entities when dissolved.
In a metaphorical sense, can be used to describe a two-fold source of irritation or preservation, or a two-part structure that maintains distinct components within a single form.
Linguistics
Semantic Notes
Refers specifically to a solid crystalline structure in chemistry. The components are present in a fixed molecular ratio. Not the same as a salt dissolved in double the water.
Dialectal Variation
British vs American Usage
Differences
No significant difference in usage or definition between BrE and AmE in the scientific context.
Connotations
Purely technical/scientific. No colloquial or idiomatic usage.
Frequency
Exclusively found in chemistry texts, lectures, and research papers in both varieties.
Vocabulary
Collocations
Grammar
Valency Patterns
N is a double salt of X and Y.The double salt crystallizes from solution.X and Y combine to form the double salt Z.Vocabulary
Synonyms
Neutral
Weak
Vocabulary
Antonyms
Usage
Context Usage
Business
Not used.
Academic
Used almost exclusively in chemistry and materials science contexts.
Everyday
Extremely rare to non-existent in everyday conversation.
Technical
Core term in inorganic and analytical chemistry.
Examples
By Part of Speech
adjective
British English
- The double salt formation was confirmed by X-ray analysis.
American English
- They studied the double salt properties under various conditions.
Examples
By CEFR Level
- In the lab, we made a double salt called alum.
- Potassium aluminium sulphate is a common double salt used in water purification and tanning.
- The research focused on synthesising novel double salts to exploit their unique magnetic and conductive properties in the solid state.
Learning
Memory Aids
Mnemonic
Think of a 'salt shaker' with TWO different coloured salts (e.g., white and blue) mixed together in perfect 1:1 layers, but when shaken into water, they separate into their own ions.
Conceptual Metaphor
A MARRIED COUPLE LIVING IN ONE HOUSE: Two distinct entities (salts) sharing a single, ordered structure (the crystal lattice) but maintaining their individual identities (ions) when active (dissolved).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not translate literally as 'двойная соль' without confirming the chemical context, as this could be misinterpreted as simply 'twice the amount of salt'.
- The Russian chemical term is 'двойная соль', but the conceptual understanding is key.
Common Mistakes
- Confusing it with a mixture of two salts. A double salt has a fixed stoichiometry.
- Using it to mean 'extra salty' or 'twice as much salt'.
- Thinking it remains combined in solution (it dissociates).
Practice
Quiz
What is the defining characteristic of a double salt when dissolved in water?
FAQ
Frequently Asked Questions
No. A complex salt gives a complex ion in solution (e.g., [Cu(NH3)4]²⁺). A double salt dissociates into simple ions of its components.
No, that would be confusing. You should say 'twice the amount of salt' or 'double the salt'.
Yes, common alum (potassium aluminium sulphate dodecahydrate, KAl(SO4)2·12H2O) is a classic pedagogical example of a double salt.
Virtually nowhere. It is a highly specialised scientific term. You might see it in historical texts on alchemy, industrial chemistry patents, or advanced material science articles.