The Hill system (or Hill notation) is a system of writing chemical formulas such that the number of carbon atoms in a molecule is indicated first, the number of hydrogen atoms next, and then the number of all other chemical elements subsequently, in alphabetical order. When the formula contains no carbon, all the elements, including hydrogen, are listed alphabetically.
By sorting formulas according to the number of atoms of each element present in the formula according to these rules, with differences in earlier elements or numbers being treated as more significant than differences in any later element or number — like sorting text strings into lexicographical order — it is possible to collate chemical formulas into what is known as Hill system order.
The Hill system was first published by Edwin A. Hill of the United States Patent and Trademark Office in 1900. It is the most commonly used system in chemical databases and printed indexes to sort lists of compounds.
Read more about Hill System: Example
Famous quotes containing the words hill and/or system:
“For most of the guys killings got to be accepted. Murder was the only way everybody stayed in line. You got out of line, you got whacked. Everybody knew the rules.”
—Nicholas Pileggi, U.S. screenwriter, and Martin Scorsese. Henry Hill (Ray Liotta)
“Television is an excellent system when one has nothing to lose, as is the case with a nomadic and rootless country like the United States, but in Europe the affect of television is that of a bulldozer which reduces culture to the lowest possible denominator.”
—Marc Fumaroli (b. 1932)