sulfate

sulfate — noun

1. the US way of writing the word that British English spells as 'sulphate'; both f

1.nounintransitive
Definition

the US way of writing the word that British English spells as 'sulphate'; both forms have the same chemical meanings

Example

In American scientific journals, they write 'sulfate' with an 'f'.

US vs UK spelling difference

The spelling 'sulfate' is standard in US chemistry textbooks.

Usage Note

This sense is purely a spelling variant. In Taiwan, English-language chemistry materials tend to follow US spelling conventions, so 'sulfate' is the more common form seen locally.

2. a chemical substance formed when sulfuric acid reacts with a metal, alkali, or o

2.nounintransitiveB2
Definition

a chemical substance formed when sulfuric acid reacts with a metal, alkali, or other base; many sulfates are used in fertilizers, cleaning products, medicines, and industrial processes

Example

The river contained high levels of sulfate from agricultural runoff.

sulfate as an environmental pollutant

Copper sulfate is often used to control algae in swimming pools.

Common collocations
  • sulfate content
  • sulfate levels
  • sulfate minerals
  • sulfate compounds
  • sulfate salts

Grammar Patterns

sulfate + of + metal/element

Usage Note

Countable when referring to a specific type of sulfate (e.g. 'three different sulfates'), uncountable when referring to the general substance. The word often appears as a modifier before another noun, as in 'sulfate salts' or 'sulfate minerals'.

Common Mistakes

The water contains sulfate of sodium.
The water contains sodium sulfate.
In chemistry, the metal or element name comes before 'sulfate', not after it with 'of'.

3. a tiny particle (a negatively charged ion, known as an anion) made of one sulfur

3.nounintransitiveC1
Definition

a tiny particle (a negatively charged ion, known as an anion) made of one sulfur atom and four oxygen atoms, written as SO₄²⁻; this ion is the part of a sulfate compound that carries its chemical properties

Example

A sulfate ion carries a negative charge of two and is very stable in water.

sulfate ion as a charged particle

In this reaction, the sulfate group is replaced by a chloride ion.

Common collocations
  • sulfate ion
  • sulfate group
  • sulfate anion
  • sulfate radical
Synonyms

Grammar Patterns

sulfate + ion / group / anion

Usage Note

Distinguish from noun sense 2: sense 3 refers specifically to the ionic particle (SO₄²⁻) itself, not to a full salt or ester compound. This sense is used mainly in discussions of chemical bonding, reaction mechanisms, and ionic equations.

Common Mistakes

The sulfate formula is SO₄.
The sulfate formula is SO₄²⁻.
The sulfate ion carries a 2− charge, which must be shown in chemical equations.

sulfate — verb

Word family

  • sulfuric
    adjectiveB2
  • sulfurous
    adjectiveC1
  • sulfur
    nounB2
  • sulfite
    nounC1
  • sulfide
    nounC1
  • sulfonate
    noun / verbC2

Synonym discussion

Sense: noun/2

These four terms all relate to the element sulfur but refer to different chemical forms. 'Sulfate' (SO₄²⁻) is the most oxidized form and the one most commonly encountered in everyday products — shampoos contain sodium laureth sulfate, and Epsom salt is magnesium sulfate. 'Sulfite' (SO₃²⁻) has one fewer oxygen atom and is used as a food preservative in dried fruit and wine. 'Sulfide' (S²⁻) has no oxygen at all and often smells like rotten eggs; it is found in minerals such as pyrite. 'Sulfur' is the pure element itself, a yellow solid. In short: sulfate has 4 oxygens, sulfite has 3, sulfide has none, and sulfur is the element. The different endings signal different chemical behaviour: for instance, sulfate salts are generally stable and safe, while sulfides can be toxic or flammable.

sulfate ↗sulfitesulfidesulfur

Common collocations

Nouns

  • sulfate content
  • sulfate levels
  • sulfate concentration
  • sulfate compound
  • sulfate salt
  • sulfate mineral
  • sulfate ion
  • sulfate solution

Phrases

  • a sulfate of [metal/element]
  • high in sulfate
  • low in sulfate

Prepositions

  • sulfate of [metal/element]
  • sulfate in [solution/soil/water]

Etymology

LatinFrenchEnglish

The word 'sulfate' comes from the modern Latin 'sulphas' (stem 'sulfat-'), built from 'sulfur' (the element) plus the chemical suffix '-ate', which chemists use to name salts of oxygen-containing acids. The suffix '-ate' indicates the form with the highest number of oxygen atoms — compare 'sulfite' (fewer oxygens) and 'sulfide' (no oxygen). The US spelling with 'f' ('sulfate') became standard in American English during the 19th-century spelling reforms, while British English kept the 'ph' spelling ('sulphate') reflecting the Greek root 'theion' via Latin.