A catalyst is a compound which allows a chemical reaction to occur without undergoing a chemical change itself. Thus it is not 'used up' when performing its function. Thus the word catalyst is a common metaphor for something which is not expended when used.

Is there a word to mean the opposite? For example food and firewood can only be used once. In usage they are, by definition, expended. They are examples of _______.

This is in contrast with, say, a nappy, which is still a nappy after being soiled. However a clean nappy might be an example of a _______ as after used it is no longer a clean nappy.

I would love if _____ were also a piece of chemistry jargon which passed into lay usage.

  • What has that to do with catalysis? A catalyst is more of something else than not being used up. – Kris Apr 27 '15 at 13:26
  • What do you understand the word catalyst to mean? – Daron Apr 27 '15 at 13:28
  • The fact that a catalyst is not changed by the chemical reaction it allows does not make it a metaphor for something that is not expended when used. I have never heard that usage and I would be very confused were I to hear it. I contend the word 'catalyst' is a common metaphor for "that which [triggers and] facilitates an outcome". Therefore you are not looking for a synonym of 'catalyst'. – Marv Mills Apr 27 '15 at 14:31
  • Not every word has an opposite - most do not! Ask for what you want, but don't call it an opposite. It would be just as valid to call something which wasn't consumed but had no effect on the reaction the opposite of a catalyst, or something which induced a change and somehow absorbed more matter from the reaction. – curiousdannii Apr 27 '15 at 14:48
  • I would not suggest every word has an opposite. But I would expect at least a technical term to exist for a compound which is expended as part of a chemical reaction. – Daron Apr 27 '15 at 15:04

Food and firewood are examples of fuel. In addition to being the raw material for synthesis of complex living tissue, food is basically fuel for the production of energy, without which no chemical reaction would occur in the living organism. Thus, these consumables could, metaphorically, be referred to as fuel.

  • I have discovered the word reactant, which the IUPAC define as 'A substance that is consumed in the course of a chemical reaction'. That's pretty much the technical term I'm looking for. But it doesn't have as nice a ring to it as the word I remember once remembering. So fuel. That's a beautiful answer. – Daron Apr 27 '15 at 15:09

If are looking for a word to refer to something that has a single use, after which it is expended, I would use the word disposable or expendable.

If you are looking, on the other hand, to a word that conveys the oppossite meaning of 'speedign up a reaction', then you may use retardant

According to Collins (http://www.collinsdictionary.com/dictionary/english/catalyst?showCookiePolicy=true):



1) a substance that increases the rate of a chemical reaction without itself suffering any permanent chemical change Compare inhibitor (sense 2)
2) a person or thing that causes a change

So retardant might be the word you are looking for in the sense that instead of speeding a reaction, it slows it down.

According to Collins (http://www.collinsdictionary.com/dictionary/english/retardant?showCookiePolicy=true):



1) a substance that reduces the rate of a chemical reaction

  • It would be much more constructive to explain the reason for the downvote... – SamuelVimes Apr 28 '15 at 7:46

A direct negation of a catalyst is an inhibitor. Meaning it specifically prevents something from happening, instead of triggering it.

What you're focusing on is whether or not the item is consumed in the process (which a catalyst by definition isn't).

I'd stick to referring to it as a consumable (product), or that it "is consumed in the process".


Reactant or reagent

A reagent /riˈeɪdʒənt/ is a substance or compound added to a system to cause a chemical reaction, or added to test if a reaction occurs. The terms reactant and reagent are often used interchangeably—however, a reactant is more specifically a substance consumed in the course of a chemical reaction.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.