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This produces an ionic bond with covalent character. A cation having inert gas like configuration has less polarizing power in comparison to cation having pseudo-inert gas like configuration. Graph of percentage ionic character. The situation is different in the case of aluminum fluoride, AlF 3. In this case, iodine is replaced by fluorine, a ...
Using the electroneutrality principle the assumption is made that the Co-N bond will have 50% ionic character thus resulting in a zero charge on the cobalt atom. Due to the difference in electronegativity the N-H bond would 17% ionic character and therefore a charge of 0.166 on each of the 18 hydrogen atoms.
For example, Na–Cl and Mg–O interactions have a few percent covalency, while Si–O bonds are usually ~50% ionic and ~50% covalent. Pauling estimated that an electronegativity difference of 1.7 (on the Pauling scale ) corresponds to 50% ionic character, so that a difference greater than 1.7 corresponds to a bond which is predominantly ionic.
Pauling proposed an equation to relate the "ionic character" of a bond to the difference in electronegativity of the two atoms, [5] although this has fallen somewhat into disuse.
It also dicusses the percent of ionicity. It would be useful to also include the equation by which percent ionicity can be calculated. % ionic character of a bond = 1 - exp (1/4 * delta chi ^2) where delta chi is the difference between electronegativity of the anion and cation.
For typical ionic solids, the cations are smaller than the anions, and each cation is surrounded by coordinated anions which form a polyhedron.The sum of the ionic radii determines the cation-anion distance, while the cation-anion radius ratio + / (or /) determines the coordination number (C.N.) of the cation, as well as the shape of the coordinated polyhedron of anions.
The circumstances under which a compound will have ionic or covalent character can typically be understood using Fajans' rules, which use only charges and the sizes of each ion. According to these rules, compounds with the most ionic character will have large positive ions with a low charge, bonded to a small negative ion with a high charge. [25]
[9] [10] One estimate puts the percentage of ionic character of alkyllithium compounds at 80 to 88%. [ 11 ] In allyl lithium compounds, the lithium cation coordinates to the face of the carbon π bond in an η 3 fashion instead of a localized, carbanionic center, thus, allyllithiums are often less aggregated than alkyllithiums.