Oxygen covalent radius

The strain energies of these five-membered heterocycles are relatively small with values of 23.5, 24.8 and S.SkJmoF estimated for tetrahydrofuran, pyrrolidine and tetrahy-drothiophene respectively (74PMH(6)199). The closeness of the values for the two former compounds reflects the almost identical covalent radii of oxygen (0.66 A) and nitrogen (0.70 A) atoms. The sulfur atom with a much larger covalent radius of 1.04 A causes a... 

To accommodate this problem, scientists have come up with several approaches to measuring atomic sizes. A common one is called the covalent radius, which is half the distance between the nuclei of two identical atoms. This technique works well for atoms such as hydrogen or oxygen, both of which readily pair up to form and O2. But how would one determine the covalent radius of a noble gas, which exists only as single atoms ... 

Note that the N3- ion (radius 171 pm) is much larger than the nitrogen atom, for which the covalent radius is only 71 pm. The oxygen atom (radius 72 pm) is approximately half the size of the oxide ion... 

A simple model for this compound with both the five-rings planar gives an O — O distance oi about bid A, while BbSlEGOBBS [3] value for the covalent radius of oxygen is 1 23 A. Consequently there must be... 

Hightened reactivity of functional groups (e.g. Cl, Br, OH, OR, OCOR, NH2, SH) at the atoms of silicon, aluminum, titanium, phoshorus and other elements in comparison with their reactivity binded with oxygen. This is due to the fact that the silicon atom is one and a half times bigger than the carbon atom it has a covalent radius of 0.117 nm, whereas the radius of the carbon atom is only 0.077 nm. It follows that functional groups of the Si atom are much more distanced from each other than... 

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