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Preface and site entrance

The water molecule

The structure of the water molecule

Water's lone pairs
Water electronic structure

ortho-water and para-water
Water dimer
Water models
Water reactivity

Easier introduction to the water molecule

H2COW [Plug-in, ActiveX] animation

The molecular orbitals of water, H2O

Hydrogen bonding in water

Hydrogen bonds
Water hydrogen bonds
Hydrogen bond cooperativity
Hydrogen bonds and solubility
Rearranging hydrogen bonds
Bifurcated hydrogen bonds
Information transfer

Easier introduction to hydrogen bonding in water

(H2O)2 COW [Plug-in, ActiveX] animation

 All-cis (H2O)5, COW [Plug-in, ActiveX] animation

 Global minimum, COW [Plug-in, ActiveX] animation

The molecular orbitals of a water dimer, (H2O)2

The molecular orbitals of a water cyclic pentamer, (H2O)5

The Phase Diagram of water

Phase diagrams

The phase diagram of water

Density change
Triple points
Ice phases

Known ices

Very high pressure ices

Ice 0 Jmol animation

Computer ices (ice 0)

Vonnegut's ice-nine
Ice crystal data

Ice IJmol animation

Hexagonal ice

Ice nucleation and growth
Is ice slippery?

Ice IJmol animation

Ice Ih/1c (Ice Isd) Jmol animation

Ice II Jmol animation

Ice III Jmol animation

Ice IV Jmol animation

Ice V Jmol animation

Ice VI Jmol animation

Ice VII Jmol animation

Ice VIII Jmol animation

Cubic ice (Ic/XIc)

Alternating 2-D Layers (Ice Ic/ Ice Ih; Ice Isd)









Ice X Jmol animation

Ice XI Jmol animation

Ice XII Jmol animation

Ice XIII Jmol animation

Ice XIV Jmol animation







Amorphous ice and glassy water

Cold metastable water
Ultraviscous water and the glass transition temperature
Low-density amorphous ice (LDA)
High-density amorphous ice (HDA)
Very-high density amorphous ice (VHDA)

Clathrate ices I, II and H

 Clathrate ice I, Jmol animation

 Clathrate ice II, Jmol animation

 Clathrate ice H, Jmol animation

CS-I clathrate
CS-II clathrate
HS-III clathrate
Other structures

Molecular vibration and absorption of water

Water and global warming

Absorption spectra of gaseous, liquid and solid water
The vibrational spectra of liquid water
The visible and UV spectra of liquid water
Absorption and penetration

Water dissociation, 2H2O = H3O+ + OH-

The ionic product, Kw


Variation in Kw with temperature and pressure

pKa and pKb
Hydrogen ions
Hydroxide ions
Grotthuss mechanism
Diffusion of hydrogen ions
Diffusion of hydroxyl ions

H3O+ COW [Plug-in, ActiveX] animation

OH- COW [Plug-in, ActiveX] animation

The molecular orbitals of the H3O+ and OH- ions

H3O2- COW [Plug-in, ActiveX] animation

 Asymmetric H5O2+, COW [Plug-in, ActiveX]

 Symmetric H5O2+, COW [Plug-in, ActiveX]

The molecular orbitals of the hydrated hydroxide ion, H3O2-

The molecular orbitals of the dihydronium ions, H5O2+

Water at interfaces

Confined water

Hydrophobic confinement

Hydrophilic confinement
Capillary rise

Interfacial water and water-gas interfaces

The surface of water
Thermodynamics of the liquid-gas surface for water


Evidence for nanobubbles
The effect of surface charge on surface tension and nanobubble stability

Seventy one anomalous properties of water

The range of anomalous properties of water

Phase anomalies P1-P13

Water has unusually high melting point
Water has unusually high boiling point
Water has unusually high critical point
Solid water exists in a wide variety of stable structures
The thermal conductivity, shear modulus and transverse sound velocity of ice reduce with increasing pressure
The structure of liquid water changes at high pressure
Supercooled water has two phases
Liquid water is easily supercooled but glassified with difficulty
A liquid water phase exists at very low temperatures
Liquid water may be easily superheated
Hot water freezes faster than cold water; the Mpemba effect
Warm water vibrates longer than cold water
Water molecules shrink as the temperature rises and expand as the pressure increases

Density anomalies D1-D22

The density of ice increases on heating (up to 70 K)
Water expands on freezing
Pressure reduces ice's melting point
Liquid water has a high density that increases on heating
The surface of water is denser than the bulk
Pressure reduces the temperature of maximum density
There is a minimum in the density of supercooled water
Water has a low thermal expansivity
Water's thermal expansivity reduces at low temperatures
Water's thermal expansivity increases with increased pressure
The number of nearest neighbors increases on melting
Nearest neighbors increases with temperature
Water has unusually low compressibility
The compressibility drops as temperature increases
The compressibility-temperature maximum
The speed of sound increases with temperature up to 74 °C
The speed of sound may show a minimum
'Fast sound' is found at high frequencies
NMR relaxation time is very small at low temperatures
The NMR shift increases to a maximum at low (supercool) temperatures
The refractive index of water has a maximum value
The change in volume as liquid changes to gas is very large

Material anomalies M1-M15

No aqueous solution is ideal
D2O and T2O differ significantly from H2O
Liquid H2O and D2O differ significantly in their phase behavior
H2O and D 2O ices differ significantly in their quantum behavior
The mean kinetic energy of water's hydrogen atoms increases at low temperature
Solutes have varying effects on water's properties
Non-polar gases solubility decreases with temperature
The dielectric constant of water is high
The relative permittivity shows a temperature maximum
Proton and hydroxide ion mobilities are anomalously fast
The electrical conductivity of water rises to a maximum
The electrical conductivity of water rises with frequency
Acidity constants of weak acids show temperature minima
X-ray diffraction shows an unusually detailed structure
Under high pressure water molecules move apart

Thermodynamic anomalies T1-T11

The heat of fusion of water exhibits a maximum at -17 °C
Water has higher specific heat capacity than ice or steam
The specific heat capacity (CP and CV) is unusually high
The specific heat capacity CP has a minimum at 36°
The specific heat capacity (CP) has a maximum
The specific heat capacity (CP) has a pressure minimum
The heat capacity (CV) has a maximum
High heat of vaporization
High heat of sublimation
High entropy of vaporization
The thermal conductivity of water is high

Physical anomalies F1-F10

Water has unusually high viscosity
Large viscosity and Prandtl number increase as the temperature is lowered
Water's viscosity decreases with pressure below 33 °C
Large diffusion decrease as the temperature is lowered
The self-diffusion of water increases with the density
The thermal diffusivity rises to a maximum at about 0.8 GPa
Water has unusually high surface tension
Some salts give a surface tension minimum; the Jones-Ray effect
Some salts prevent the coalescence of small bubbles
The molar ionic volumes of salts show maxima with respect to temperature

Properties of water and its isotopologues

Short properties list for liquid H2O

Changes in some properties with temperature (-30 °C - 100 °C)

Changes in some further properties with temperature (0 °C - 373 °C)

Important constants and conversion factors

Periodic Table

Unexpected properties of water

Vapor pressure-Temperature behavior

Pressure-Temperature-Density behavior

Volume-Temperature behavior

Temperature-viscosity behavior

Temperature-enthalpy of vaporization relationship

Water molecular models

Water model parameterization

Water model descriptions
Water model properties

Water clustering in liquid water

 (H2O)8 equilibria animation

Overview of the structuring in liquid water

Water clustering
Cluster and H-bond lifetimes are independent
Icosahedral water cluster

Introduction to water clustering

Water's two-state cluster history

Outline of methods for investigating water structure

Why different methods give different water structures?
Dielectric spectroscopy
Diffraction methods
Nuclear Magnetic Resonance (NMR)

Osmotic stress
Physical properties
Vibrational spectra
X-Ray spectroscopy

(H2O)100 and (H2O)280 clusters Jmol animation

(H2O)280 cluster equilibria Jmol animation

Tetrahedral (H2O)14 cluster Jmol animation

The icosahedral (H2O)280 water clusters

Tetrahedral units
Icosahedral clusters
Cluster equilibria
Cluster density
Sub-structures of the icosahedral water cluster
Connectivity map of the water icosahedron
Solid geometry of the icosahedral cluster (Java)

Super cluster ((H2O)280)13 Jmol animation

Super network ((H2O)100)n Jmol animation

Cluster puckering Jmol animation

Tetrahedra cluster Jmol animation

Bicyclo-octamers cluster Jmol animation

Super clusters of water molecules

Water cluster equilibria, puckering and temperature effects

Water icosahedral cluster architecture

Explanation of water cluster equilibria using animated gifs

Spherical coordinates of the icosahedral water clusters

Shell radii and occupancy of the icosahedral water clusters

Superstrand Jmol animation

Alternative icosahedral clusters Jmol animation

Alternative tetrahedral clusters Jmol animation

 Cavities and networks, Jmol animation

 Clathrate-like, Jmol animation

Super clusters of water molecules

Alternative icosahedral clustering of water

Alternative tetrahedral clustering of water

Water cluster architecture, based on gas clathrates

Paper model of an icosahedral water structure

Paper model of an truncated icosahedral water structure

Plain paper model of the layers of a truncated icosahedral water structure

Evidence for icosahedral water clusters

The radial distribution function
Other support from diffraction data
Support from clathrate structures
Evidence from amorphous ice and low density water
Other evidence

Water cluster conclusions


Protein hydration

The contribution of water to protein structure

Water in protein recognition and binding
Water in protein function

Protein folding and denaturation
Protein folding
Protein crystallization
Protein denaturation

Nucleic acid hydration

DNA hydration
DNA processing

Inositol Jmol animation

Cyclodextrin Jmol animation

Sugar hydration

Aqueous properties of the cyclodextrins

Polysaccharide hydration
Alternatives for defining bound and unbound water
Polar effects, for example, α-D-galacturonic acid
Weak hydrogen bonding, for example, α-L-arabinofuranose
Strong hydrogen bonding, for example, β-1-4-linked D-xylose
Hydrophobic effects, for example, β-1-4-linked D-xylose
Effects of other solutes: non-ionic
Effects of other solutes: ionic
Conclusions concerning polysaccharide hydration

Introduction to polysaccharides

Chart showing the furan pseudorotational angles of ribose and deoxyribose

Hydrocolloids and gums

Hydrocolloid polymers


Mixtures of hydrocolloids
Effect on viscosity
Hydrocolloid action

Agar Jmol animation

Alginate Jmol animation

Arabinoxylan Jmol animation

Carrageenan Jmol animation

CMC Jmol animation

Cellulose Jmol animation

Curdlan Jmol animation

Gelatin Jmol animation










β-Glucan Jmol animation


Gum arabic

Guar gum Jmol animation

Locust bean gum Jmol animation

Pectin Jmol animation

Starch Jmol animation

Xanthan gum Jmol animation

Guar gum

Locust bean gum



Xanthan gum

Hydrocolloid rheology

Structural effects
Further rheological terminology

Hydrocolloids and health (Dietary fiber)

Dietary fiber
The colon
Colonic fermentation
Water-holding capacity (WHC)
Viscosity and gel formation
Binding to bile acids

Ion hydration and aqueous solutions of salts

Methods for determining ion hydration
Water clustering around ions

SO42 cluster Jmol animation

Sulfate and other large anions

The Hofmeister series

H3O+ magic number cluster Jmol animation 

The H3O+ magic number cluster ions

Water clustering around the SO42- cluster

CO2 cluster Jmol animation

Water clustering around the CO2 cluster

Kosmotropes and chaotropes 

Definitions of kosmotropes and chaotropes

Ionic kosmotropes and chaotropes
Non-ionic kosmotropes and chaotropes

Hydrophobic hydration

The hydrophobic effect
Extensive hydrophobic interfaces
Solubility effects
Salting-out and salting-in
Alcoholic solutions

Carboxylate link Jmol animation

Intracellular water

Intracellular solutions contain more K+ ions
Membranes help create a tendency towards low density water in cells
The effect of intracellular protein on water structuring
The importance of protein carboxylate groups
The importance of protein mobility
Cooperative conversion of the water structuring
Actin, tubulins and the intermediate filaments

Water on Earth
The origin of Earth's water
Water availability
Water use
Reverse osmosis

Water and life
Can life exist without water?
Consequences of changes in water’s hydrogen bond strength
Estimating the effect of changes in water hydrogen bond strength
Effect of water hydrogen bond strength on melting and boiling point
Effect of hydrogen bond strength on the temperature of maximum density
Effect of water hydrogen bond strength on kosmotropes and chaotropes
Effect of water hydrogen bond strength on its dissociation
Effect of water hydrogen bond strength on biomolecule hydration
Effect of water hydrogen bond strength on its other physical properties
Conclusions concerning water and life

Water and health

Water content
Water balance
Water requirements
Water roles
Water for drinking

Magnetic and electric effects on water

Electric effects on water
Magnetic effects on water
Electromagnetic effects on water
Magnetic descaling of water
Water redox processes
Driving cars using water

Water and microwaves

Dielectric loss
Effect of salt
Electromagnetic penetration

Dielectric constant and polarization

Background information and definitions
Polarization and polarizability
Refractive index

The complex dielectric permittivity behavior of water

The complex dielectric permittivity

Water activity

Colligative properties of water

Overview of colligative properties : mole fraction : molarity, molality, % w/w and % w/v
Vapor pressure lowering : CaCl2
Freezing point depression : examples : Glucose : Urea : Ethanol : NaCl : CaCl2
Boiling point elevation : Glucose
Osmotic pressure
Self-generation of osmotic pressure at interfaces

Osmotic pressure stabilises nanobubbles

Molarity and molality

Aqueous biphasic systems

Polyoxomolybdate systems

{Mo132} nanodrop Jmol animation

 nanodrop + fullerene, Jmol animation

{Mo154} nanowheel Jmol animation

{Mo132} nanocapsule and aqueous nanodrop

Molybdenum blue {Mo154} nanowheel

How does the {Mo154} nanowheel hydrate?
How do the nanowheels form large spherical clusters?

 Single C60, Jmol animation

(C60)13 cluster, Jmol animation

Aqueous solutions of fuillerenes, C60 and C70

Frequently asked questions concerning liquid water

How can hot water freeze quicker than cold water?

Can increasing pressure prevent water from freezing?

Is water good for you?

Is water blue?

Why does salt lower the freezing point of water?

Does water have a memory?

Does magnetic descaling of water work?

How can a liquid have a structure?

Does the radial distribution peak at about 3.7 Å exist?

Is there fine structure in the radial distribution function?

Do interstitial water molecules exist?

Icosahedral clustering and the two-state mixture model?

Water-related material


What ist homeopathy?

Published evidence for and against homeopathy
Homeopathic solutions
Does homeopathy work?

Memory of water

Does water have memory?

Is water special?
Does the glassware matter?
Is gas important?
Does dilution happen as predicted?
Solutions are more complex than expected
Peroxide and radical production in water
Possible scenarios for the memory effect in homeopathic solutions

'Polywater', declustered water and other waters

Clustered and 'declustered' water

Fullerane Jmol animation

Platonic solids Java animation

Novel fulleranes

Platonic solids, water and the golden ratio

Contributed papers

 pdf file

J. G. Watterson, Enzyme function: random events or coherent


Book reviews

Aqueous systems at elevated temperatures and pressures

Handbook of refractive index and dispersion of water for scientists and engineers

References (currently 2582)

1 - 100

101 - 200

201 - 300

301 - 400

401 - 500

501 - 600

601 - 700

701 - 800

801 - 900

901 - 1000

1001 - 1100

1101 - 1200

1201 - 1300

1301 - 1400

1401 - 1500

1501 - 1600

1601 - 1700

1701 - 1800

1801 - 1900

1901 - 2000

2001 - 2100

2101 - 2200

Visitor's Book, recent postings

Visitor's Book archive, 2000-2003

Visitor's Book archive, 2004-2006

Add to Visitor's Book

 Links with animation

 Earlier publications




Water related links

Martin Chaplin CV


Site news

Minor edits

Site Table of Contents



Enzyme Technology ebook



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This page was last updated by Martin Chaplin on 10 September, 2014

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