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Formula of Water (H2O)

Identification of Water Chemical Compound

2D chemical structure image of water
Chemical Formula H2O
Molecular Weight 18.01528 g/mol
IUPAC Name water
SMILES String O
InChI InChI=1S/H2O/h1H2
InChIKey XLYOFNOQVPJJNP-UHFFFAOYSA-N

Chemical Formula Description

The water molecule contains a total of 3 atom(s). There are 2 Hydrogen atom(s) and 1 Oxygen atom(s). A chemical formula of water can therefore be written as:

H2O

The chemical formula of water shown above is based on the molecular formula indicating the numbers of each type of atom in a molecule without structural information, which is different from the empirical formula which provides the numerical proportions of atoms of each type.

The above chemical formula is the basis of stoichiometry in chemical equations, i.e., the calculation of relative quantities of reactants and products in chemical reactions. The law of conservation of mass dictates that the quantity of each element given in the chemical formula does not change in a chemical reaction. Thus, each side of the chemical equation must represent the same quantity of any particular element based on the chemical formula.

3D chemical structure image of water
Ball-and-stick model of water

chemical table area

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Input a chemical compound consisting of C, H, N, O, S, F, Cl, Br, I, Si, P, and/or As atom(s)

Input example for Ethanol:

  • Name: ethanol
  • CAS #: 64-17-5
  • Formula: C2H5OH
  • Smiles: CCO
  • InChI: InChI=1S/C2H6O/c1-2-3/h3H,2H2,1H3
  • InChIKey: LFQSCWFLJHTTHZ-UHFFFAOYSA-N

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Additional Information for Identifying Water Molecule

  • Structure Data File (SDF/MOL File) of water

    The structure data file (SDF/MOL File) of water is available for download in the SDF page of water providing the information about the atoms, bonds, connectivity and coordinates of water, which is not completely available in the chemical formula representation. The water structure data file can be imported to most of the cheminformatics software for further analysis and visualization.

  • Chemical structure of water

    The chemical structure image of water is available in chemical structure page of water, which specifies the molecular geometry, i.e., the spatial arrangement of atoms in the chemical formula of water and the chemical bonds that hold the atoms together.

  • Molecular weight of water

    The molecular weight of water is available in molecular weight page of water, which is calculated as the sum of the atomic weights of each constituent element multiplied by the number of atoms of that element specified in the chemical formula of water.


  • InChI (IUPAC International Chemical Identifier) information of water

    The molecular chemical formulas lack structural information. An alternative textual expression including the structural information is InChI. The full standard InChI of water is:

    InChI=1S/H2O/h1H2

    It can provide a standard way to encode the molecular information of water to facilitate the search for the compound information in databases and on the web.

    The condensed, 27 character standard InChIKey (hashed version of the full standard InChI) of water is:

    InChIKey=XLYOFNOQVPJJNP-UHFFFAOYSA-N

    The InChIKey may allow easier web searches for water, but it needs to be linked to the full InChI to get back to the original structure of the water since the full standard InChI cannot be reconstructed from the InChIKey.

  • Other names (synonyms) or registry numbers of water

    The water compound may have different names depending on the various different situations of industrial applications. The list of the other names (synonyms) of water including the registry numbers is given below, if available:

    • AR-1L8208
    • OXO
    • HYD
    • eau
    • DIS
    • 8O
    • 558440-22-5
    • Water, for embryo transfer, sterile-filtered, BioXtra, suitable for mouse embryo
    • Water solution, contains 10.0 % (v/v) methanol, 0.10 % (v/v) trifluoroacetic acid
    • Water solution, contains 0.10 % (v/v) formic acid, 50.0 % (v/v) acetonitrile
    • Water solution, contains 0.1 % (v/v) formic acid, 20 % (v/v) acetonitrile
    • Water solution, contains 0.05 % (w/v) ammonium formate, 0.1 % (v/v) formic acid
    • Sterile Diluent for Merck Sharp & Dohme Corp. Live Attenuated Virus Vaccines
    • Water, for cell biology, free of endotoxins, ultrafiltered and autoclaved
    • Water solution, contains 0.1 % (v/v) trifluoroacetic acid, for HPLC
    • Water solution, HPLC grade, contains 0.035 % (v/v) acetic acid
    • Physicianscare Ophthalmic Solution Eyewash Purified Water, 98.3%
    • Water, sterile-filtered, BioReagent, suitable for cell culture
    • Water, for molecular biology, DEPC-treated and sterile filtered
    • Water solution, for HPLC, contains 0.1 % (v/v) formic acid
    • Water solution, contains 0.06 % (v/v) trifluoroacetic acid
    • Water solution, contains 0.05 % (v/v) trifluoroacetic acid
    • Water solution, contains 10 mM ammonium acetate, for HPLC
    • Water solution, contains 0.1 % (v/v) ammonium hydroxide
    • Density Standard 998 kg/m3, H&D Fitzgerald Ltd. Quality
    • Bacteriostatic Water for Injection USP-pre-filled Syringe
    • Water, for HPCE, for luminescence, for UV-spectroscopy
    • I14-102543
    • Water, deuterium-depleted, <=1 ppm (Deuterium oxide)
    • Water solution, contains 0.10 % (v/v) acetic acid
    • Water solution, contains 0.05 % (v/v) acetic acid
    • Water solution, 0.005N in sulfuric acid, for HPLC
    • Diluting Medium for Insulin Zinc Injectable Suspension
    • First Aid Direct Buffered Eyewash Sterile Isotonic
    • Water, deuterium-depleted, 99.99995 atom %
    • D00001
    • Water, packaged for use in deposition systems
    • Water, deuterium depleted, deuterium 2-3 ppm
    • Diluting Medium for Soluble Insulin Injection
    • Diluting Medium for Isophane Insulin Injection
    • Water, ACS reagent, for ultratrace analysis
    • Sterile purified water in containers (JP17)
    • Fad First Aid Direct Buffered Eye and Skin
    • Emergency Eye Wash, Pw, Sterile Ster-aide
    • Water, ultrapure, Spectrophotometric Grade
    • Water for injection in containers (JP17)
    • Plum Duo Emergency Eyewash Ph Neutralizing
    • A-med Brand First Aid Eye and Skin-rinse
    • Sterilized Water for Injections Ph. Eur.
    • Sterile Isotonic Buffered Genuine Eyewash
    • Physicianscare Ophthalmic Solution Eyewash
    • Airlife Sterile Water for Inhalation USP
    • Xpect Buffered Eyewash Sterile Isotonic
    • Sterile Water for Injection 100% USP
    • 558440-53-2
    • Xpect First Aid Buffered Eye and Skin
    • RTR-011310
    • Bacteriostatic Water for Injection USP
    • Water with 0.1% trifluoroacetic acid
    • Sterile Water for Injection, U.S.P.
    • Sterile Water for Inhalation USP 3ml
    • Plum Emergency Eyewash Ph Neutralizing
    • E-Toxate(TM) Water, endotoxin, free
    • Sterile Water for Inhalation U.S.P.
    • Purified water in containers (JP17)
    • Collyrium for Fresh Eyes - Eye Wash
    • Water, tested according to Ph.Eur.
    • Medi-first Plus First Aid Eye Wash
    • Walgreens Sterile Soothing Eye Wash
    • Water, deionized water, ACS 1L
    • Sperian Eyesaline Emergency Eyewash
    • [OH2]
    • Sterile Water for Injection, USP
    • Salinaax Eye Wash and Skin Flush
    • Xpect First Aid Buffered Eyewash
    • Sterile Water for Irrigation USP
    • Sterile Water for Inhalation USP
    • Water, Molecular Biology Reagent
    • Water for Injection Sterile USP
    • Sterile Water for Injection USP
    • Hydrogen hydroxide (HH or HOH)
    • HMDB02111
    • Green Guard First Aid Eye Wash
    • Aerowash Eyewash and Skin-rinse
    • Water, BioPerformance Certified
    • Medi-first First Aid Eye Wash
    • Bacteriostatic water for injection in plastic container
    • 059QF0KO0R
    • Water, ultrapure, HPLC Grade
    • WATER, For PCR Applications
    • Water, for ion chromatography
    • Water for injection (JP17)
    • Fad First Aid Direct Eyewash
    • C C(KO
    • Water, demineralized, p.A.
    • GLUCOSE 4-O4 GROUP
    • Cederroth Emergency Eye Wash
    • DEUTERIUM OXIDE- D
    • Water, HPLC gradient grade
    • Thesafetydirector Aquapreserv
    • Sterile water for injection in plastic container
    • Dihydrogen monoxide (DHMO)
    • Water, RNase, DNase-free
    • Distilled water, for HPLC
    • Plum Duo Emergency Eyewash
    • Water, for TOC analysis
    • Water (JP17/USP)
    • Sperian Eyesaline Eyewash
    • Purified water (JP17)
    • Eyewash Flushing Solution
    • Water, purified (USP)
    • DISORDERED SOLVENT
    • an unknown oxygen source
    • Water, sterile filtered
    • Water for Injection BP
    • Physicianscare Eye Wash
    • Industrial Neutral-eyes
    • Plum Emergency Eyewash
    • OXO GROUP
    • Water, Endotoxin-free
    • Water, DEPC-Treated
    • BOUND OXYGEN
    • HYDROXY GROUP
    • Family Care Eye Wash
    • Haws Eyewash Additive
    • Water, LC/MS
    • Sterile water (TN)
    • Water, PCR Reagent
    • UNKNOWN
    • Rugby Eye Irrigating
    • Water, HPLC Plus
    • Water, HPLC grade
    • Water, ACS reagent
    • First Aid Eye Wash
    • Eyesaline Concentrate
    • Water, HPLC
    • Bacteriostatic Water
    • Pure Water Density Standard, UKAS ISO/IEC17025 and ISO Guide 34 certified, density: 0.9982 g/mL at 20 C, density: 0.9970 g/mL at 25 C
    • Water for injection, bacteriostatic
    • Scienceware Eyewash
    • Medi-first Eyewash
    • Sterile Water Inj
    • Salinaax Eye Wash
    • Sterile water in plastic container
    • Eys Eye Wash
    • Buffered Eye-lert
    • Boraqua Eye Wash
    • Major Eye Wash
    • Hydrohydroxic acid
    • hydrogen hydroxide
    • Eye Wash
    • DI water
    • Bouton Eye Wash
    • Eye Clean
    • Hydrogen monoxide
    • water-
    • Eye Stream
    • Dorama-neo
    • Water Additive
    • Sterile Diluent
    • Hydric acid
    • Eye Irrigating
    • Aqua Purificata
    • Hydroxic acid
    • Hydroxy radical
    • Water for irrigation, sterile
    • Water for inhalation, sterile
    • Wasser
    • Ocufresh
    • Eyewash
    • Tritiotope
    • Water for injection, sterile
    • dihydridooxygen
    • acqua
    • Sterile water for inhalation
    • Water, sterile purified
    • Water, purified sterile
    • Water for hemodialysis
    • Sterile purified water
    • UNK
    • GTE
    • Pur-wash
    • aqua
    • agua
    • Water, distilled, conductivity or of similar purity
    • HOH
    • DEUTERIUM OXIDE- D
    • MFCD00011332
    • Water, for HPLC
    • Hydrol
    • Ice
    • Bacteriostatic water for injection
    • BOUND WATER
    • H2O
    • Water (distilled)
    • Sterile water for irrigation
    • Sterile water for injection
    • Water for injection
    • Water, distilled
    • Water, sterile
    • oxidane
    • Deionized water
    • DHMO
    • steam
    • Dihydrogen Monoxide
    • Water, mineral
    • Sterile water
    • Water, deionized
    • Water, purified
    • Water vapor
    • 7732-18-5
    • Purified water
    • Distilled water
    • Dihydrogen oxide

Water Identification Summary Frequently Asked Questions (FAQs)

What’s the chemical formula of water?
H2O
How many atoms and what are they in the water structure?
3 atom(s) - 2 Hydrogen atom(s) and 1 Oxygen atom(s)
How many chemical bonds and what are they in the water structure?
2 bond(s) - 1 water molecule(s)
What’s the molecular weight of water?
18.01528 g/mol
What’s the SMILES string of water?
O
What’s the InChI of water?
InChI=1S/H2O/h1H2
What’s the InChIKey of water?
XLYOFNOQVPJJNP-UHFFFAOYSA-N

4368 The contents of this page can freely be shared if cited as follows:
Source: Chemical Compounds Deep Data Source (CCDDS; https://www.molinstincts.com) based on 41 patented QSQN and QN technology
commercialized into Mol-Instincts database and ChemRTP, ChemEssen, Inc (2024).

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