Bond energy
You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.
Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [1] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.
In chemistry, bond energy (E) is a measure of bond strength in a chemical bond. For example the carbon-hydrogen bond energy in methane E(C–H) is the enthalpy change involved with breaking up one molecule of methane into a carbon atom and 4 hydrogen radicals divided by 4. Bond energy (E) should not be confused with bond dissociation energy.
Another example: an O–H bond of a water molecule (H–O–H) has 493.4 kJ mol-1 of bond dissociation energy, and 424.4 kJ mol-1 is needed to cleave the remaining O–H bond. The bond energy of the O–H bonds in water is 458.9 kJ mol-1, which is the average of the values.
Some bond energy trends (units are in kcal/mol and (kJ/mol)) :
| H | F | Cl | Br | I | OH | N | NH2 | |
|---|---|---|---|---|---|---|---|---|
| bond energies H–X | 104 (436) | 135 (570) | 103 (431) | 87 (366) | 71 (298) | 119 (498) | 110 ( 460) | — |
| bond energies CH3–X | 105 (440) | 109 (452) | 84 (352) | 70 (293) | 56 (236) | 91 (382) | — | 87 (365) |
Bond energy/distance correlation
Bond strength (energy) can be directly related to the bond distance. Therefore we can use the metallic, ionic, or covalent radii of each atom in the molecule to determine the bond strength. For example, the covalent radius of boron is estimated at 83.0 pm, but the bond length of B–B in B2Cl4 is 175 pm, a significantly larger value. This would indicate that the bond between the two boron atoms is a rather weak single bond. In another example, the metallic radius of rhenium is 137.5 pm, with a Re–Re bond length of 224 pm in the compound Re2Cl8. From this data, we can conclude that the bond is a very strong bond or a quadruple bond. This method of determination is most useful for covalently bonded compounds .
What determines Bonding Energy
There are several contributing factors but usually the most important is the difference in the electronegativity of the two atoms bonding together.
See also
External links
References
- ^ Handbook of Chemistry & Physics 65th Edition CRC Press ISBN 0-8493-0465-2
- ^ Alcock, N.W. Bonding and Structure: structural principles in inorganic and organic chemistry Ellis Horwood Ltd., New York. 1990 pp. 40-42.
- ^ http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/B/BondEnergy.htmlar:طاقة رابطةja:結合エネルギー
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
