Covalent radius: group 1
When two atoms of the same kind are bonded through a single bond in a neutral molecule, then one half of the bond length is referred to as the covalent radius. This is unambiguous for molecules such as Cl2, the other halogens, and for other cases such as hydrogen, silicon, carbon (as diamond), sulphur, germanium, tin, and a few other cases. However for oxygen, O2, the situation is less clear as the order of the oxygen-oxygen bond is double. In this case, and indeed for most of the periodic table, it is necessary to infer the covalent radius from molecules containing O-O single bonds or from molecules containing a C-X bond in which the covalent radius of X is known.
The data for s- and p-block elements is broadly consistent across a number of sources but note that the values quoted for N (70 pm), O (66 pm), and F (60 pm) are sometimes less than those quoted here. Also the value for hydrogen is sometimes given as 30 pm. Soemtimes sources give the values for the Group 1 and Group 2 metals as larger than those given here.
It may be necessary to treat the values for the d-block elements with some caution. Values are not often given in most sources.
- R.T. Sanderson in Chemical Periodicity, Reinhold, New York, USA, 1962.
- L.E. Sutton (ed.) in Table of interatomic distances and configuration in molecules and ions, Supplement 1956-1959, Special publication No. 18, Chemical Society, London, UK, 1965.
- J.E. Huheey, E.A. Keiter, and R.L. Keiter in Inorganic Chemistry : Principles of Structure and Reactivity, 4th edition, HarperCollins, New York, USA, 1993.
- W.W. Porterfield in Inorganic chemistry, a unified approach, Addison Wesley Publishing Co., Reading Massachusetts, USA, 1984.
- A.M. James and M.P. Lord in Macmillan's Chemical and Physical Data, Macmillan, London, UK, 1992.
You can buy periodic table posters, mugs, T-shirts, fridge magnets, games, molecular models, and more at the WebElements shop
- Search WebElements
- Search Chemistry Web
- Essential data
- The elements round us
- Compounds: halides, oxides, sulfides, hydrides, and complexes; lattice energies; and reduction potentials
- Reactions of : reactions with air; water; halogens; acids; and bases
- Electronegativities: Pauling; Sanderson; Allred-Rochow; Mulliken-Jaffe; and Allen
- Bond enthalpies of diatomic species
- Lattice energies: oxides and halides
- Element properties
- Physics properties: boiling point; melting point; density; and molar volume; thermal conductivity; and electrical resistivity; bulk modulus; critical temperature; superconductivity temperature; hardness (mineralogical, Brinell, and Vickers); linear expansion coefficient; Poisson's ratio; reflectivity; refractive index; rigidity modulus; Young's modulus; and velocity of sound
- Crystal structure
- Thermochemistry: enthalpies of atomisation, fusion, and vaporisation, thermodynamic properties
- Atom properties
- Electronic properties: electronic configuration; term symbol; electron affinity; ionisation energies; and atomic spectra
- Atom sizes: atomic radii; Shannon and Pauling Ionic radii; covalent radius; metallic radius; element bond length; and Van der Waals radius
- Electron shell properties: effective nuclear charge; electron binding energies; and valence orbital radii maxima
- Nuclear properties
Search Chemistry Web