Ronald Gillespie
Encyclopedia
Ronald James Gillespie, CM
(August 21, 1924), a chemistry
professor at McMaster University
, specializes in the field of Molecular Geometry
in Chemistry. In 2007 he was awarded the Order of Canada
.
He was educated at the University of London
obtaining a B.Sc in 1945, a Ph.D in 1949 and a D.Sc in 1957. He was Assistant Lecturer and then Lecturer in the Department of Chemistry at University College London
in England
from 1950 to 1958. He moved to McMaster University
, Hamilton, Ontario
, Canada
in 1958 and is now emeritus professor. He was elected as a Fellow of the Royal Society of Canada
in 1965 and a Fellow of the Royal Society of London in 1977.
Gillespie has done extensive work on expanding the idea of the Valence Shell Electron Pair Repulsion (VSEPR) model of Molecular Geometry, which he developed with Ronald Nyholm, and setting the rules for assigning numbers. He has written several books on this VSEPR topic in chemistry
. With other workers he developed LCP theory
, (ligand close packing theory), which for some molecules allows geometry to be predicted on the basis of ligand-ligand repulsions. Gillespie has also done extensive work on interpreting the covalent radius of fluorine
. The covalent radius
of most atoms is found by taking half the length of a single bond between two similar atoms in a neutral molecule. Calculating the covalent radius for fluorine
is more difficult because of its high electronegativity
compared to its small atomic radius
size. Ronald Gillespie’s work on the bond length of fluorine focuses on theoretically determining the covalent radius of fluorine by examining its covalent radius when it is attached to several different atoms.
Order of Canada
The Order of Canada is a Canadian national order, admission into which is, within the system of orders, decorations, and medals of Canada, the second highest honour for merit...
(August 21, 1924), a chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
professor at McMaster University
McMaster University
McMaster University is a public research university whose main campus is located in Hamilton, Ontario, Canada. The main campus is located on of land in the residential neighbourhood of Westdale, adjacent to Hamilton's Royal Botanical Gardens...
, specializes in the field of Molecular Geometry
Molecular geometry
Molecular geometry or molecular structure is the three-dimensional arrangement of the atoms that constitute a molecule. It determines several properties of a substance including its reactivity, polarity, phase of matter, color, magnetism, and biological activity.- Molecular geometry determination...
in Chemistry. In 2007 he was awarded the Order of Canada
Order of Canada
The Order of Canada is a Canadian national order, admission into which is, within the system of orders, decorations, and medals of Canada, the second highest honour for merit...
.
He was educated at the University of London
University of London
-20th century:Shortly after 6 Burlington Gardens was vacated, the University went through a period of rapid expansion. Bedford College, Royal Holloway and the London School of Economics all joined in 1900, Regent's Park College, which had affiliated in 1841 became an official divinity school of the...
obtaining a B.Sc in 1945, a Ph.D in 1949 and a D.Sc in 1957. He was Assistant Lecturer and then Lecturer in the Department of Chemistry at University College London
University College London
University College London is a public research university located in London, United Kingdom and the oldest and largest constituent college of the federal University of London...
in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
from 1950 to 1958. He moved to McMaster University
McMaster University
McMaster University is a public research university whose main campus is located in Hamilton, Ontario, Canada. The main campus is located on of land in the residential neighbourhood of Westdale, adjacent to Hamilton's Royal Botanical Gardens...
, Hamilton, Ontario
Hamilton, Ontario
Hamilton is a port city in the Canadian province of Ontario. Conceived by George Hamilton when he purchased the Durand farm shortly after the War of 1812, Hamilton has become the centre of a densely populated and industrialized region at the west end of Lake Ontario known as the Golden Horseshoe...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
in 1958 and is now emeritus professor. He was elected as a Fellow of the Royal Society of Canada
Royal Society of Canada
The Royal Society of Canada , may also operate under the more descriptive name RSC: The Academies of Arts, Humanities and Sciences of Canada , is the oldest association of scientists and scholars in Canada...
in 1965 and a Fellow of the Royal Society of London in 1977.
Gillespie has done extensive work on expanding the idea of the Valence Shell Electron Pair Repulsion (VSEPR) model of Molecular Geometry, which he developed with Ronald Nyholm, and setting the rules for assigning numbers. He has written several books on this VSEPR topic in chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
. With other workers he developed LCP theory
LCP theory
In chemistry, ligand close packing theory , sometimes called the ligand close packing model describes how ligand – ligand repulsions affect the geometry around a central atom. It has been developed by R.J Gillespie and others from 1997 onwards and is said to sit alongside VSEPR which was...
, (ligand close packing theory), which for some molecules allows geometry to be predicted on the basis of ligand-ligand repulsions. Gillespie has also done extensive work on interpreting the covalent radius of fluorine
Covalent radius of fluorine
The covalent radius of fluorine is a measure of the size of a fluorine atom; it is approximated at about 60 picometres.Since fluorine is a relatively small atom with a large electronegativity, its covalent radius is difficult to evaluate. The covalent radius is defined as half the bond lengths...
. The covalent radius
Covalent radius
The covalent radius, rcov, is a measure of the size of an atom that forms part of one covalent bond. It is usually measured either in picometres or angstroms , with 1 Å = 100 pm....
of most atoms is found by taking half the length of a single bond between two similar atoms in a neutral molecule. Calculating the covalent radius for fluorine
Fluorine
Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...
is more difficult because of its high electronegativity
Electronegativity
Electronegativity, symbol χ , is a chemical property that describes the tendency of an atom or a functional group to attract electrons towards itself. An atom's electronegativity is affected by both its atomic number and the distance that its valence electrons reside from the charged nucleus...
compared to its small atomic radius
Atomic radius
The atomic radius of a chemical element is a measure of the size of its atoms, usually the mean or typical distance from the nucleus to the boundary of the surrounding cloud of electrons...
size. Ronald Gillespie’s work on the bond length of fluorine focuses on theoretically determining the covalent radius of fluorine by examining its covalent radius when it is attached to several different atoms.
Publications
- Chemical Bonding and Molecular Geometry: From Lewis to Electron Densities (Topics in Inorganic Chemistry) by Ronald J. Gillespie and Paul L. A. Popelier
- Atoms, Molecules and Reactions: An Introduction to Chemistry by Ronald J. Gillespie
- Chemistry by Ronald J. Gillespie, David Humphreys, Colin Baird, and E. A. Robinson