01Aug 2019 by Vincent Summers 1 Comment

Don’t Monkey Around – What is a Banana Bond?

Chemistry, Education
A banana bond is not a typical chemical bond by any stretch of the imagination. It is a 3-center, 2-electron bond. The shape of this kind of bond resembles a banana, hence its name. Perhaps the simplest example of a banana bond is demonstrated between boron and hydrogen in the diborane molecule, B2H6. Elemental Atomic Orbitals We begin with a discussion of the much simpler, more typical 2-center, 2-electron single bond. When atoms form molecules, the atomic orbitals involved transform into molecular orbitals. Let's consider a very simple example. Say we want to form one C-H bond of the molecule methane (CH4). Now hydrogen atoms only have one electron. The single electron lies in the 1s2 orbital. That type of orbital possesses spherical symmetry. Unlike hydrogen, carbon has 12 electrons…
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27Jul 2019 by Vincent Summers No Comments

The Curiously Stable Dodecaborate Dianion

Chemistry
There is a lot of talk concerning the chemistry of carbon. And this is totally appropriate. The chemistry of carbon is the chemistry of life. But little is known about boron, which is right next door to carbon on the periodic table of the elements. Yet, boron is a most interesting element. For one thing, boron, like carbon, is capable of bonding to itself. Boron Bonds to Itself There are many compounds in which the element does just that, it bonds to itself. Consider a few of its combinations with hydrogen (see the image). As you advance to larger boron-hydrogen structures, however, it becomes clear the molecular bonding for boron differs considerably from the hydrocarbons. Dodecaborane Dodecaborane somewhat resembles dodecahedrane (C20H20) in outward appearance, even though in terms of bonding,…
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27Nov 2014 by Vincent Summers No Comments

LCAO MO Chemical Bonding Theory and Examples

Chemistry
[caption id="attachment_8903" align="alignright" width="440"] Antibonding sigma orbital.[/caption] LCAO MO The nature of the chemical bond has been of interest for hundreds of years. Theories have been developed to explain how atoms combine to form molecules. The most successful theory to date is the (L)inear (C)ombination of (A)tomic (O)rbitals - (M)olecular (O)rbitals or LCAO MO bonding theory. You've got it: yet another acronym. Atoms have nuclei. These contain protons and neutrons. Electrons travel around these nuclei. Orbitals are mathematical functions that describe their trajectories. As atoms form molecules, atomic orbitals combine to form molecular orbitals. Since orbital functions are described by the Schrödinger wave equation and that equation is linear, molecular orbitals can be described by the linear additive combining of atomic orbitals. Example of Hydrogen Ordinary hydrogen has one proton,…
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