Global Molecular Identification from Graphs. IV. Molecules with Four Closed p-Shell Atoms and beyond
Chris J. Walters, Ken Caviness, Ray Hefferlin · 2003
The identification of main-group molecules having atoms with closed valence p shells, i.e., having atoms with eight valence electrons, is continued into the realm of four-atom molecules. All possible covalently-bonded species, obtained from two independent computer programs, are shown. The method for generalizing to molecules in which some or all atoms have closed valence s shells, i.e., having atoms with two valence electrons, is recalled. A list of all proto-type linear/bent four-atom molecules, with dative bonds in addition to covalent and/or van der Waals bonds, is presented (permutations having been culled out). A program code, lists of mol-ecules based on other graphs, and lists of five- and covalently-bonded six-atom species, are available on the Web. For molecules derived from the two other four-vertex graphs, their vast numbers require extensive indexing schemes for the results to be useful. The paper concludes with some preliminary observations concerning the stabilities of four-atom molecules having atoms with closed shells. Instead of classifying the observed means of knotting neckties, »Physicists Thomas Fink and Yong Mao... set out to learn how many ways you can manipulate a tie... in nine or fewer moves. Mathematical modeling revealed the answer: 85. But only 13, including 9 new ones, were aesthetically pleasing.«