More than Twelve Atoms

Boranes Containing More than Twelve Boron Atoms.196... 

Among of the systems under study, clusters with three, five, six and twelve atoms possess higher symmetries having more than a twofold rotational axis. As a result doubly degenerate librational states occur in these complexes. In Fig. 10 one of the possible representations of these degenerate states in the HCl(Ar)i2 cluster is displayed, however, any linear combination of these functions is also valid. Three pronounced recurrences shown in Fig. 10 demonstrate repeated collisions of hydrogen with the cluster. The situation becomes dramatically different for photolysis started from the first non-degenerate librationally excited state. In this... 

How big of a number does the mole represent Promise not to panic— one mole represents a set of 602,000,000,000,000,000,000,000 items So, just as a dozen eggs represents twelve eggs, a mole of carbon atoms represents 602,000,000,000,000,000,000,000 carbon atoms. This is an incredibly large number, but I assure you that such a large number is entirely necessary when dealing with atoms. For example, the last time that you took a sip of water, you likely held more than 602,000,000,000,000,000,000,000 atoms in your mouth ... 

Figure 13. The number of molecules containing a given number of carbon atoms for anthracene shock simulations with shock direction along the a axis at impact velocities of ten (solid bars) and twelve (open bars) km/s. The peaks for unreacted anthracene molecules (14 carbons) are far off scale with more than 1200 molecules.

Atoms of the second-period elements cannot have more than eight valence electrons around the central atom, bnt atoms of elements in and beyond the third period of the periodic table form some compounds in which more than eight electrons snrronnd the central atom. In addition to the 3s and 3p orbitals, elements in the third period also have 3d orbitals that can be nsed in bonding. These orbitals allow an atom to form an expanded octet. One componnd in which there is an expanded octet is snlfnr hexafluoride, a very stable compound. The electron configuration of snlfnr is [Ne]3x 3p". In SFg, each of snlfnr s six valence electrons forms a covalent bond with a flnorine atom, so there are twelve electrons around the central sulfur atom ... 

---