Reducing agent
element or compound that loses (or "donates") an electron to another chemical species in a redox chemical reaction; losing electrons,oxidized,"reduces" (are "oxidized" by) oxidizers (oxidizing agents)
In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an electron recipient (called the oxidizing agent, oxidant, oxidizer, or electron acceptor).
Examples of substances that are common reducing agents include hydrogen, carbon monoxide, the alkali metals, formic acid, oxalic acid, and sulfite compounds.
In their pre-reaction states, reducers have extra electrons (that is, they are by themselves reduced) and oxidizers lack electrons (that is, they are by themselves oxidized). This is commonly expressed in terms of their oxidation states. An agent's oxidation state describes its degree of loss of electrons, where the higher the oxidation state then the fewer electrons it has. So initially, prior to the reaction, a reducing agent is typically in one of its lower possible oxidation states; its oxidation state increases during the reaction while that of the oxidizer decreases.
Thus in a redox reaction, the agent whose oxidation state increases, that "loses/donates electrons", that "is oxidized", and that "reduces" is called the reducer or reducing agent, while the agent whose oxidation state decreases, that "gains/accepts/receives electrons", that "is reduced", and that "oxidizes" is called the oxidizer or oxidizing agent.
For example, consider the overall reaction for aerobic cellular respiration:
C6H12O6(s) + 6O2(g) → 6CO2(g) + 6H2O(l)
The oxygen (O2) is being reduced, so it is the oxidizing agent. The glucose (C6H12O6) is being oxidized, so it is the reducing agent.
Characteristics
Consider the following reaction:
2 [Fe(CN)6]4− + Cl2 → 2 [Fe(CN)6]3− + 2 Cl−
The reducing agent in this reaction is ferrocyanide ([Fe(CN)6]4−).
This brief starts where responsible research should: with the source description of “Reducing agent” as element or compound that loses (or "donates") an electron to another chemical species in a redox chemical reaction; losing electrons,oxidized,"reduces" (are "oxidized" by) oxidizers (oxidizing agents). Everything that follows is an evidence route, not borrowed authority.
Why this record matters
The subject matters to the science & nature register because the source frames it as element or compound that loses (or "donates") an electron to another chemical species in a redox chemical reaction; losing electrons,oxidized,"reduces" (are "oxidized" by) oxidizers (oxidizing agents). Its deeper value depends on whether names, dates, institutions and citations support that framing.
Datasets, specimens, observations and peer-reviewed methods provide the appropriate test for the technical claims summarized here. The source revision retrieved here is dated Sep 8, 2026. The linked authority identifier is Q216830. None of the 0 selected statements returned an explicit reference.
Scientific names, classifications and consensus can change while older terminology persists in catalogues and historical literature. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Check terminology, classification and the date of the cited evidence. Scientific names and technical consensus can change while older records retain historical value.
- Current terminology
- Classification context
- Finding cited technical literature
Primary datasets, specimen catalogues, standards bodies and the most recent peer-reviewed literature.
Three-step research path
- Establish the record: confirm the title “Reducing agent”, its source revision and the description used here.
- Expand the search: follow Reducing agent primary sources, Reducing agent archive and Reducing research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Reducing agent”?
- Which observation, specimen, dataset or publication supports the account?
- Is the terminology current, historical or disputed?
Search terms from this dossier
This entry incorporates text from “Reducing agent” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.