Ice rules
Encyclopedia
In chemistry, ice rules are basic principles that govern arrangement of atom
s in water ice
. They are also known as Bernal–Fowler rules, after British physicists John Desmond Bernal and Ralph H. Fowler
.
The rules state each oxygen
is covalently bonded
to two hydrogen
atoms, and that the oxygen atom in each water molecule forms up to two hydrogen bonds with other oxygens.
In other words, in ordinary Ih ice every oxygen is bonded to the total of four hydrogens, two of these bonds are strong and two of them are much weaker. Every hydrogen is bonded to two oxygens, strongly to one and weakly to the other. The resulting configuration is geometrically an ordered lattice periodic lattice, but the distribution of weak vs. strong bonds is disordered.
A nice figure of the resulting structure can be found in.
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...
s in water ice
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...
. They are also known as Bernal–Fowler rules, after British physicists John Desmond Bernal and Ralph H. Fowler
Ralph H. Fowler
Sir Ralph Howard Fowler OBE FRS was a British physicist and astronomer.-Education:Fowler was initially educated at home but then attended Evans' preparatory school at Horris Hill and Winchester College...
.
The rules state each oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
is covalently bonded
Covalent bond
A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....
to two hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
atoms, and that the oxygen atom in each water molecule forms up to two hydrogen bonds with other oxygens.
In other words, in ordinary Ih ice every oxygen is bonded to the total of four hydrogens, two of these bonds are strong and two of them are much weaker. Every hydrogen is bonded to two oxygens, strongly to one and weakly to the other. The resulting configuration is geometrically an ordered lattice periodic lattice, but the distribution of weak vs. strong bonds is disordered.
A nice figure of the resulting structure can be found in.
External links
- Bernal–Fowler rules in Glossary of Meteorology. http://amsglossary.allenpress.com/glossary/search?id=bernal-fowler-rules1
- Exposition by Chris Wilson and Brett Marmo. http://virtualexplorer.com.au/special/meansvolume/contribs/wilson/Bernard-Fowler.html