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Dihydrogen oxide


Q. What is dihydrogen oxide, and what is it used for. If you can help I would appreciate it greatly.

Anderson Dillan
- St. Paul, Minnesota


A. `You're joking, aren't you? Write down what the chemical formula of dihydrogen oxide would be - look familiar?

Bill Reynolds
Bill Reynolds [deceased]
consultant metallurgist - Ballarat, Victoria, Australia
We sadly relate the news that Bill passed away on Jan. 29, 2010.

A. Dihydrogen oxide is a widely used fire extinguishing agentplus an indispensable solvent for life processes.

Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

A. Dihydrogen oxide is used extensively in industry for the dilution of waste streams for treatment by the waste treatment system. It is also known to cause incredible erosion into igneous formations.

Dan Brewer
chemical process supplier - Gurnee, Illinois


Basel [last name deleted for privacy by Editor]
- Los Angeles, California


A. O doesn't exist, it's either O2 or O with a valence of -2, unless it's O3.

tom pullizzi animated    tomPullizziSignature
Tom Pullizzi
Falls Township, Pennsylvania

A. Plasmatic Oxygen is simply O because it's energy state is too high to form any long term chemical bonds. So O exists.

Jon Mayo
- San Jose, California

The chemical symbol for oxygen is 'O' But when written as itself, not part of a chemical bond it is written as O2. This is because there must be 2 oxygen atoms, otherwise they explode when in contact with other air particles, because the outer electron shell is not full. Having 2 oxygen atoms together completes the shell and makes it full. This is year 8 science.

Stephanie S. [last name deleted for privacy by Editor]
- Ballarat, Victoria, Australia

By the way O2 exists in nature as O2 for the exact reason that it will not constantly react and cause explosion, this already happened in the formation of earth. But in reality oxygen is actually O. The Oxygen we breathe is O2 and the oxygen in the ozone layer is O3. But oxygen itself is just O.

Rafi Matta
- Mississauga, Ontario, Canada

It can be fatal when experienced in sufficient quantities under unfortunate circumstances.

Noelle B. [last name deleted for privacy by Editor]
- Chattanooga, Tennessee

DiHydrogen Oxide: Formed from an extremely energetic chemical reaction between its constituent elements, producing enough heat to melt most metals, it then becomes a very stable molecule. It's melting point is low, and it's boiling point relatively low, it is nontoxic in moderate quantities, and is used in many manufacturing processes, including food preparation. Extremely effective solvent, can be used for many cleaning purposes, except for some fabrics. Reacts strongly to alkali metals, releasing Hydrogen in the process, producing an explosive gas.

Wayne Blackburn
Computer Support - Cincinnati, Ohio

A common myth about Dihydrogen Monoxide is that it is poisonous and it should be avoided, although it is a very bad idea to believe. Con artists trick normal peoples' minds to believe that Dihydrogen Monoxide is bad; although, when you think about is clearly the prefix di means 2, and the chemical symbol for Hydrogen is H. Now we got H2. The prefix mon means 1 and oxide is a word for oxygen; therefore, we add all these symbols together we get H2O which is of course water. Now we should realize that this is a bad trick that must be nipped in the bud. Thanks for your time.

Colin Trundle
- Alexandria, Kentucky, USA

Dihydrogen oxide is water and it hurts... yes it does if I were to throw an ice cube at you it would hurt wouldn't it? If I pour hot water on you I am sure that will also hurt. People water is harmful..

Carlos Arkidzon
- Placentia, California

When you balance the equation dihydrogen oxide you have the H2, which equals +2nd the O that equals -2. That is why the equation is H20. Therefore, monoxide exists in compounds.

Lisa Strunk
- Kingman, Arizona

There's a difference between water and dihydrogen monoxide. Water is H20 but covalent. Dihydrogen monoxide is ionic. Oxide is O2-, which means it gives two electrons to two hydrogen atoms, then giving 2H+. And we all know what happens in an ionic reaction, so I won't go further. Thus, dihydrogen monoxide is NOT water, but IS H20.

Adam Large
- Los Angeles, California

Water, Water, Water.. is the answer.H2O is the answer. Surely, isn't it at least 60 percent that's what we really are. So, that's why we love it, deep inside. O, and U2.

Victor Panebianco
- nsw, in Sydney, Australia


Water makes up 80% of our body mass...

Gem Mel
- Sheffield, South Yorkshire, UK

H2O. It is just exaggerated over the internet. I think it is just like the "Global Warming" scandal. Politicians just trying to get elected.

Jordan Smith
- Heltersberg, Rheinland-Pfalz, Germany


Dihydrogen monoxide is not the correct name for the compound with the chemical formula H2O.. AND IS NOT WATER

Dihydrogen monoxide is some layman's obvious attempt to try and fabricate a scientific name for water, but didn't know the basic principles of naming compounds!

The correct 'scientific' name for water is hydrogen oxide!

H2O is a 2 element, nonmetal-nonmetal compound and the prefixes mon-, di-, tri-, tetra- etc.. only apply to the second element!

Like Ca2O is Calcium oxide, not dicalcium oxide!

H2CO3 is hydrogen carbonate, not dihydrogen carbonate!

P2O5 is Phosphorus pentoxide, not diphosphorus pentoxide!

Mr Williams
- Sydney, Australia

The mono- prefix is often dropped for the second-named element if it is the only common compound the elements form. Thus referring to H2S as hydrogen monosulfide is much rarer than the name hydrogen sulfide. However, since carbon and oxygen can form several compounds (carbon monoxide, carbon dioxide, tricarbon dioxide, and dicarbon monoxide), the mono- prefix is kept, as it is with silicon monoxide and silicon dioxide. Indeed, hydrogen and oxygen do form another common compound, H2O2. Using prefix nomenclature this compound would be called dihydrogen dioxide, also known as hydrogen peroxide. Thus, keeping the mono- in dihydrogen monoxide does serve to distinguish it from another compound.

Tom Milac
- Sierra Vista, Arizona
February 3, 2008

Mr. Williams from Sydney,
you are missing something..
it is dihydrogen monoxide because they are non-metals.
you use prefix in covalent compounds, when non-metals are bonded together..

just thought I could add some note..*^^*
by the way, this is grade 10 science!

Katarina L [last name deleted for privacy by Editor]
- Toronto, Ontario, Canada
May 19, 2008

Dihydrogen Oxide/ dihydrogen monoxide is water and is NOT a misnomer, as Mr. Williams from Sydney suggests. Saying that Dihydrogen monoxide should simply be called hydrogen monoxide would be like saying benzene (C6H6) is the same as butyne (C4H6), because although they are definitely different, they should both be called carbon hexahydrogen because you don't put a prefix on the carbon. This is, of course, according to your instructions, Mr. Williams. Please do not confuse people, if I didn't know better, that review would have brought me a failing grade in my class had I read it then. I'm truly sorry if this review rubs against you in the wrong way, I would just like to make sure that undeserved grades are not given because of the would-be-misled students who read your answer and listened to it.

Shelby H [last name deleted for privacy by Editor]
- Wake Forest, North Carolina
August 17, 2008

Hi Shelby. Neither Mr. Williams nor any other poster owes anyone the obligation to remain silent under fear that their posting will not agree with your teacher.

The people in charge of such conventions note that the important thing is that you convey to the listener what substance you are speaking of. I think you'll find that prefixes like 'di' and 'mono' are added to avoid ambiguity, and usually omitted if there is no chance of ambiguity.

But the need for clarity trumps the small sin of superfluity or redundancy; so I believe that ALL of the terms are acceptable. Those arcane "conventions" that some readers have quoted clearly PERMIT omission of numerical prefixes, but I think they do not demand it.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
August 20, 2008

October 9, 2008

Naming Binary molecule follows this role.

The least electronegative atom are named first and the other atom is modified with the suffix -ide. If there are more than one atom which made up the Least electronegative part of the molecule it is numbered with Greek numerical prefix.

H2O Di-hydrogen oxide. Note Hydrogen is less electronegative than oxygen

Thus Di-hydrogen oxide is the Systematic nomenclature name for water

Salem Phillip
- La Pastor Santa Cruz, Trinidad

May 21, 2009

I wish the grade school teachers would take some Physics before they teach about molecules. All this discussion about one of the best-and-yet-worst molecules in existence on Earth, and detected in inter-stellar space, but somewhat lacking on most other bodies of the "Solar System". One question not clear yet is, does this molecule exist on bodies orbiting other stars.

(Please do not call them "other Suns" because we do try to give a different name to each star, and our closest star is the only one called "Sun", or more properly, "Helios". Let's all call our system "the Helios system". Now try it, everybody. Say "Helios System". Wasn't that nice? And don't call dirt "earth", but you can call it "soil".)

But you all should know that the proper name for the molecule under discussion is Oxygen-dihydrate. (Still chuckling from grading my students.)

R W. McCrackin
Emeritus Physics Professor - Corvallis, Oregon

Russell McCrackin,

You forgot another common, non-"Sun" name for the primary star of our system.


As much of the popular culture, science, and literature of the world refers to our system more regularly as the "Sol System", if we ever expand civilization to a point where stars are used at markers of travel and tourism, the "Sol System" is more likely to be utilized than the "Helios System".

As for Dihydrogen Oxide. It is a highly corrosive and erosive substance. It can cause respiratory concerns if inhaled, and heart failure if ingested in sufficient quantities. It is resistive to kinetic forces, and cause injury or death if one encounters a sufficient quantity at a high enough velocity.

Nurse Whitmore
- Vancouver, Canada
September 12, 2009

Professor McCrackin, you are right to chuckle about the wrong identification of 'dihydrogen oxide'.
But the alternative name you suggested for the H2O molecule, i.e. 'oxygen dihydrate', is incorrect.
According to IUPAC nomenclature guidelines, 'hydrate' means that water molecules are *added* to a chemically stable compound, e.g. manganese (II) sulphate monohydrate is MnSO4·H2O.
Therefore 'oxygen dihydrate' should be something like O2·2H20, which clearly does not exist.

I'm afraid now somebody else too is chuckling...

Andrea Pollett
- Roma (Caput Mundi), Italy
December 30, 2009

Hi, Andrea. I like your answer. It seems to suggest that we could also call H2O "nullandvoid hydrate" :-)


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

Katrina L from Toronto, Canada,
Yes, this is a grade 10 science question and I think that it is a silly one.
Thank you to all who have responded to this question before me because even though by the time I had finished reading your answers I had forgotten what the original question was, I too am chuckling. Not at you, with you.

Isabelle M [last name deleted for privacy by Editor]
- Mackay, Queensland, Australia
March 27, 2010

It is Dihydrogen Oxide, since both hydrogen and oxygen are nonmetals. Since they are both nonmetals, the first nonmetal, hydrogen, will be greek-prefix-ized according to the number of atoms. Since there were 2 hydrogen atoms, di- is the prefix. So Di + Hydrogen + Oxide (1 oxygen atom)=

Dihydrogen Oxide!

John D.
- Minneapolis, Minnesota
April 25, 2011

The History Channel show, The Universe, (from 2005, and available on Netflix), says water is hydrogen dioxide. Wouldn't this be HO2? I'm guessing they misspoke, but I would like a confirmation or rebuttal.

Ken Silva
- Phoenix, Arizona
May 30, 2011

What geeky scientists. I don't even know what H20 is... :P

Alice Andersson
- Libertyville, Illinois USA
November 20, 2011

Hi. Being from the plating industry where we deal constantly with ionization, hydrogen embrittlement, pH, hydrolysis, and generally the effects of water separating into H+ and OH - . . .

I think the name I like the name hydrogen hydroxide :-)


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
April 8, 2013

!! Excuse me, Ted, this is highly unprofessional and irrelevant. I'm extremely distressed and upset because of your response . You have 2 hours to change it. Or else.

Karen Hill
Main character - New York, New York
January 6, 2022

Sorry, Karen, we've changed it and beg your forgiveness. We all realize that the show can't go on if the main character storms off. What color M&M's did you demand again?

Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha - Pine Beach, New Jersey
January 2022

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