aqueous cation H₃O⁺, the type of oxonium ion produced by protonation of water

Ball-and-stick model of the hydronium ion
In chemistry, hydronium (hydroxonium in traditional British English) is the cation ... H3O+, the type of oxonium ion produced by protonation of water. It is often viewed as the positive ion present … Wikipedia
Factsheet
Names IUPAC name
oxonium
Other names
hydronium ion
Identifiers
CAS Number 13968-08-6 Y
Factsheet
Names IUPAC name
oxonium
Other names
hydronium ion
Identifiers
CAS Number 13968-08-6 Y
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Wikipedia
en.wikipedia.org › wiki › Hydronium
Hydronium - Wikipedia
3 weeks ago - In chemistry, hydronium (hydroxonium in traditional British English) is the cation ... H3O+, the type of oxonium ion produced by protonation of water.
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American Chemical Society
acs.org › molecule-of-the-week › archive › h › hydronium-ion.html
Hydronium ion - American Chemical Society
November 19, 2025 - All acidic aqueous solutions contain protonated water, known commonly as the hydronium ion (H3O+). Brønsted acids release one or more of their protons (hydrogen ions), which combine with water molecules.
Discussions

Does the hydronium ion (H3O+) actually exist? If so, how does H+ ion molecule bond with the water molecule, seeing as it has no electrons?
It's like any other atom, it borrows the electron from the oxygen. It's not a very powerful bond which is why H3O is a less common molecule compared to H2O More on reddit.com
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March 3, 2023
The hydronium ion H3O+ is the strongest acid that can exist in aq...
The hydronium ion H3O+ is the strongest acid that can exist in aqueous solution because stronger acids dissociate by transferring a proton to water. What is the strongest base that can exist in aqueous solution? - McMurry Chemistry 8th Edition - solution to problem 55 in chapter 16. More on pearson.com
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July 23, 2022
Hydronium ion concentration in pure water
What is your question? That, molarity was set such that you would get this concentration, in pure water, at a fairly arbitrary temperature? That is not how moles, or molarity, was defined. If your question is, was the neutral pH boundary set such that water under these conditions is neutral? Then, yes. More on reddit.com
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November 9, 2021
Calculating Hydronium ion concentration from pH (and identifying molecules based on pH)
The first problem (pH one) is correct You started the second one (which form is basic/acidic) with the right premises and reasoning but you came to the wrong conclusions. Think again about what you labelled acidic and basic. Which proton could be lost by the acidic form? Which atom could receive a proton in the basic form? More on reddit.com
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August 13, 2019
People also ask

Is hydronium a cation?
Yes. Hydronium is a cation that has a formula of H3O+. Since it has a positive charge, it classifies as a cation.
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study.com
study.com › courses › science courses › chemistry 101: general chemistry
Hydronium Ion | Definition, Formula & Calculation - Lesson | Study.com
Is H3O+ a cation?
Yes. Hydronium is a cation that has a formula of H3O+. Since it has a positive charge, it classifies as a cation.
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study.com
study.com › courses › science courses › chemistry 101: general chemistry
Hydronium Ion | Definition, Formula & Calculation - Lesson | Study.com
Is H3O+ an acid or base?
H3O+ is the sign of an acid being present. The concentration of H3O+ determines the magnitude of the acidity of a solution.
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study.com
study.com › courses › science courses › chemistry 101: general chemistry
Hydronium Ion | Definition, Formula & Calculation - Lesson | Study.com
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Chemistry LibreTexts
chem.libretexts.org › bookshelves › physical & theoretical chemistry › supplemental modules (physical and theoretical chemistry) › acids and bases › acids and bases in aqueous solutions
The Hydronium Ion - Chemistry LibreTexts
January 30, 2023 - The hydronium ion is an important factor when dealing with chemical reactions that occur in aqueous solutions. Its concentration relative to hydroxide is a direct measure of the pH of a solution.
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PubChem
pubchem.ncbi.nlm.nih.gov › compound › Oxonium
Oxonium | H3O+ | CID 123332 - PubChem
Oxonium | H3O+ | CID 123332 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety/hazards/toxicity information, supplier lists, and more.
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Jack Westin
jackwestin.com › resources › mcat-content › ions-in-solutions › hydration-the-hydronium-ion
Hydration The Hydronium Ion - Ions In Solutions - MCAT Content
July 20, 2020 - When water is used as the solvent, the dissolving process is called hydration. Hydronium is the common name for the aqueous cation H3O+, the type of oxonium ion produced by protonation of water.
Find elsewhere
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Study.com
study.com › courses › science courses › chemistry 101: general chemistry
Hydronium Ion | Definition, Formula & Calculation - Lesson | Study.com
September 18, 2017 - It occurs when a hydrogen ion combines with a water molecule. Hydronium is a cation that has a formula of H3O+. It often is made from a water molecule combined with a positively charged hydrogen ion.
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ScienceDirect
sciencedirect.com › topics › earth-and-planetary-sciences › hydronium-ion
Hydronium Ion - an overview | ScienceDirect Topics
The ability of carbonic anhydrase to catalyze the absorption of CO2 into water-containing liquids by conversion of CO2 plus water to bicarbonate and protons (or hydronium ions) and the release of CO2 from water-containing liquids containing bicarbonate and a source of protons is an inherent, defined property of carbonic anhydrase enzymes.
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Gonzaga
guweb2.gonzaga.edu › faculty › cronk › CHEM101pub › hydronium.html
CHEM 101 - Hydronium ion
March 25, 2020 - This ionic equation is commonly abbreviated by chemists by elimination of a water molecule and letting H+(aq) represent hydronium ion:
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Fiveable
fiveable.me › all key terms › organic chemistry › hydronium ion
Hydronium Ion Definition - Organic Chemistry Key Term | Fiveable
The hydronium ion, represented as H3O+, is a cation formed when a proton (H+) is added to a water molecule. It is a key player in the understanding of acid-base chemistry and the strength of acids and bases.
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Wiley Online Library
onlinelibrary.wiley.com › doi › abs › 10.1002 › 047147844X.pc291
The Hydronium Ion - David - Major Reference Works - Wiley Online Library
July 15, 2005 - The simplest representation of H+(aq) is the hydronium ion (sometimes also referred to as the oxonium ion or the hydroxonium ion), H3O+(aq), but this is just the first in a series the next few members of which are H5O2+, H7O3+, H9O4+, and in ...
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Fiveable
fiveable.me › all key terms › intro to chemistry › hydronium
Hydronium Definition - Intro to Chemistry Key Term | Fiveable
Hydronium is the positively charged ion formed when a proton (H+) is added to a water molecule (H2O), resulting in the formula H3O+. This ion plays a crucial role in understanding the concepts of pH and pOH, which are essential in the study of chemistry.
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Biology As Poetry
biologyaspoetry.com › terms › hydronium_ion.html
Hydronium Ion - Biology As Poetry
H3O+; that is, a positively charged and therefore polar substance consisting of one oxygen atom and three hydrogen atoms. Hydronium ions are cations that form from the chemical reaction of hydrogen ions, and water and are found in aqueous solution.
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University of Waterloo
uwaterloo.ca › chem13-news-magazine › december-2016-january-2017 › feature › hydronium-ion-yes-or-no
Hydronium ion: Yes or no? | Chem 13 News Magazine | University of Waterloo
December 7, 2018 - Streamlining the acid ionization equation with the H+ ion makes the weak acid the star of the show, with the emphasis on the loss of the proton from the acid. Referring to H+ as a proton also requires a bit of explanation and a few moments of digesting by most high school chemistry students, but they usually get the hang of it after a few examples. And now, many years later, I have joined the hydronium ion camp.
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Chemistry LibreTexts
chem.libretexts.org › campus bookshelves › portland community college › ch105: allied health chemistry ii › 5: acids and bases
5.2: Hydronium Ions - Chemistry LibreTexts
December 13, 2024 - Because a proton is only about one ten-thousandth as big as an average atom or ion, water dipoles can approach very close to a hydrogen ion in solution. Consequently the proton can exert a very strong attractive force on a lone pair of electrons in a water molecule—strong enough to form a coordinate covalent bond: The H3O+ formed in this way is called a hydronium ion (on the left in the figure below).
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Quora
quora.com › What-is-hydronium-What-purpose-does-it-serve
What is hydronium? What purpose does it serve? - Quora
Answer (1 of 2): Hydronium is H3O+ which is really a water molecule with an extra Proton. This makes the molecule low on the pH scale and hence, acidic! It is illusive in nature and is found in minute amounts in normal drinking water.
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Pearson
pearson.com › all textbooks › mcmurry 8th edition › ch.16 - aqueous equilibria: acids & bases › problem 55
The hydronium ion H3O+ is the strongest acid that can exist - McMurry 8th Edition Ch 16 Problem 55
According to the Brønsted-Lowry theory, acids are proton donors, while bases are proton acceptors. In aqueous solutions, the strength of an acid is determined by its ability to donate protons to water, forming hydronium ions (H3O+).
Published   July 23, 2022