Chemical substance In organic chemistry, there can be more than one chemical compound with the same composition and molecular weight. Generally, these are called isomers. Isomers usually have substantially different chemical properties, and often may be isolated without spontaneously interconverting. A common example is glucose vs. fructose. The former is an aldehyde, the latter is a ketone. Their interconversion requires either enzymatic or acid-base catalysis. However, tautomers are an exception: the isomerization occurs spontaneously in ordinary conditions, such that a pure substance cannot be isolated into its tautomers, even if these can be identified spectroscopically or even isolated in special conditions. A
Nasik magic hypercube original definition of nasik.<br> A "nasik" magic cube would have 13 magic lines passing through each of its "m" cells. (This cube also contains 9"m" pandiagonal magic squares of order "m".)<br> A "nasik" magic tesseract would have 40 lines passing through each of its "m" cells.<br> And so on. In 1866 and 1878, Rev. A. H. Frost coined the term "Nasik" for the type of magic square we commonly call "pandiagonal" and often call "perfect". He then demonstrated the concept with an order-7 cube we now class as "pandiagonal", and an order-8 cube we class as "pantriagonal".<br> In another 1878