Lewis acids and bases Lewis acids and bases A Lewis acid is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any species that has a filled orbital containing an electron pair which is not involved in bonding but may form a dative bond with a Lewis acid to form a Lewis adduct. For example, NH is a Lewis base, because it can donate its lone pair of electrons. Trimethylborane (MeB) is a Lewis acid as it is capable of accepting a lone
Magic cube classes diagonal:)<br>. Included below are references and links to discussions of the old definition<br> With the popularity of personal computers it became easier to examine the finer details of magic cubes. Also more and more work was being done with higher dimension magic Hypercubes. For example, John Hendricks constructed the world's first Nasik magic tesseract in 2000. Classed as a perfect magic tesseract by Hendricks definition. A magic hypercube of dimension "n" is perfect if all pan-n-agonals sum correctly. Then all lower dimension hypercubes contained in it are also perfect.<br> For dimension 2, The Pandiagonal Magic Square has been called "perfect"