Artificial Symmetry in Chemistry, the Melting Pot of the Sciences

Chemistry is the melting pot of sciences simply because it coalesces biology and physics unlike any other discipline can. So it only makes sense to, for the sake of these other branches, explain the concept of molecular symmetry in both horizontal and vertical aspects. The chemist Roald Hoffman (pictured here) himself an educator, advocated for a horizontal teaching method, wherein a concept should only be explained in terms of that particular science. For example, symmetry could only be explained using the apropos nomenclature found in chemistry. That will be done in this blog. Having said that, it is also deemed important for people of other scientific disciples to come together and realize the importance of molecular symmetry in their own fields. 

Another Nobel Prize winner Michael Polanyi said at his banquet that "science begins when a body of phenomena is available which shows some coherence and regularities, that science consists  assimilating these regularities in a natural way." Lets use our good ole' common sense for a second here  and recognize that symmetry is nothing more but a manifestation of these regularities. Symmetry is one way in which we can recognize rules patterns. Things like molecular motions are dependent on the rules for symmetry. 

 A symmetry operation is one where there is a "permutation" of atoms so that the molecules the atoms compose or the crystal lattice structures transforms into something that is for all intents and purposes the same as the starting state. No physical property or wave function was damaged in the making of this operation. The nuclear arrangement and other things are static when there is a symmetry operation. However, there exists dynamic properties such as electronic structure and molecular vibration. In the case of molecular vibration, it is impossible to say that a molecule has perfect symmetry in any case. Bond lengths and bond angles perpetually change when this molecule in question is not at zero Kelvin.   There is a plethora of ways vibrations can affect larger molecules (the ones synthesized in the lab, wink, wink) but let us look at H20 as an example. Here the bonds can be elongated equally, bent symmetrically, or elongated asymmetrically. One can know the symmetry of a molecule from a method called vibrational spectroscopy. 

"The sculpture is already there in the raw stone; the task of a good sculptor is merely to eliminate the unnecessary parts of the stone." I think Michelangelo was on to something. Elimination of the unnecessary to form a symmetrical figure, (a human being in the case of the artist or the molecule in the case of the chemist) is something that is seen in chemistry when it comes to bonding and intra-molecular forces. Concerning electronic structure, which is really what dictates who bonds with whom, is directly correlated with symmetry. Molecular Orbitals, which are based on Atomic Orbitals, are linear combinations of those atomic orbitals. 
There is a large number of possibilities but because many do not meet the criteria that symmetry puts forth, many are not considered to be bonding possibilities. 

Symmetry is essential in materials science. Symmetry is considered in crystals (one unit cell structures) and pseudo-crstals (more than one unit cell). After its discovery in 1982 in an electron-diffraction experiment, pseudo-crystals demonstrated ten fold symmetry which was something that was a true revolution in crystallography. Discovery and creation of  new compounds is born at this moment. Symmetry considerations now can be used to assist research in synthesis and discovery. And this is where our trek begins. The synthesis of symmetrical compounds and their implications, moral, scientific, and practical.

Why is Symmetry Important in Chemistry?

     Asking why symmetry is important to chemistry is analogous to asking why red blood cells are essential to a human being. While many people are unaware of the microscopic cells constantly flowing through their veins and capillaries, people are aware that there life would be incredibly different without these petite cells. This is akin to symmetry and its integral role in chemistry. Symmetry is involved in virtually everything ranging from a substance's boiling point to the types of bonds it contains, but never receives the credit that it deserves. When put into perspective, symmetry is involved in everything and is located everywhere.

     In organic chemistry, symmetry is incredibly important in determining a substance's boiling point. In one article, the author relates each compound to a piece in the game Tetris™. As illustrated below, the molecule which is most symmetric (labelled easy) has the capability to stack and form multiple layers, leaving few, if any, space between each layer. The piece labelled "hard", on the other hand, is able to stack with itself; however, there will be large gaps left between each layer which will result in a lower melting point than its symmetric counterpart.

     The following two diagrams further emphasize how important symmetry is when stacking molecules. Perfectly symmetric molecules can also be described as Legos™ because they fit perfectly together when stacked.

     Simply put, less gaps will occur when a symmetric molecule is stacked with itself, hence, resulting in a greater melting point.

     Another area of chemistry where symmetry comes into play is in hydrogen bonding. One specific type of hydrogen bond is named the symmetrical hydrogen bond. Just as its name implies, this variety of hydrogen bond is unique because the hydrogen atom is equidistant from two interchangeable atoms, illustrated in the diagram to the left. In the prior paragraph, it was stated that symmetry increases the intermolecular forces between molecules, and similarly, the symmetric hydrogen bonds are much stronger than a regular hydrogen bond. The strength of a symmetric hydrogen bond is comparable to that of a covalent bond. This could mean that a symmetric hydrogen bond has the potential to have almost forty times the bond energy of that of a regular hydrogen bond!

Bonds displayed in hexabenzocoronene

     Another element of symmetry that was stated previously is its role in determining differences in bonds. In an experiment conducted by Leo Gross of IBM research in Switzerland, he discovered that the bonds in a buckyball, made of 60 carbon atoms, had different strengths. Achieved for the first time in 2009, Gross used a technique that was capable of measuring individual bonds. The bonds appeared in different colors which assisted Gross and his colleagues in determining the strengths of the bond, but symmetry also came into play. The symmetry of the atom allowed the researchers to differentiate the background effects which may have been produced by the new imaging technique from the actual bonds themselves. This is seen with the image on the right (http://www.newscientist.com/article/dn22269-first-images-of-chemical-bond-differences-captured.html) . With out the scientists familiarity with the compound symmetric structure, this experiment would have been a waste!

Vitruvian Man

     Symmetry has been valued by humans ever since Leonardo da Vinci created the Vitruvian Man in 1487, a drawing that focuses on the proportions and symmetrical nature of human beings. However currently, there are many other implications of symmetry. Defined by dictionary.com as "the correspondence in size, form, and arrangement of parts on opposite sides of a plane, line, or point; regularity of form or arrangement in terms of like, reciprocal, or corresponding parts", this word has a plethora of value which its definition does not imply. Symmetry is key in determining a compounds boiling point and melting point. Scientists are attempting to create drugs with symmetrical properties in order to cure disease. Symmetry is also giving scientists a better understanding of cancer and it provides incite onto how stem cells function. Symmetry may just be another word, but it is found everywhere and its value in chemistry, and life, is indescribable.

Starting with the Basics

Undoubtedly, the most reasonable area of chemistry to start in our discussions lies in the elements that compose of all matter. Were these elements that we know about discovered or created?

First, one might expect all of the elements to have been "discovered," since humans did not first "create" such elements such as oxygen or hydrogen. Furthermore, many elements that had been artificially synthesized-- such as Technetium (Tc)--  had been found to be naturally occurring also. So is this area of chemistry actually a simple series of discoveries?

Not quite. (Of course, chemistry would not let us off that easily.) The key phrase in that previous paragraph is the reference to "many [synthesized] elements." In fact, there are elements which we know of solely by synthesis. The most recent example is about Element 117, which was successfully synthesized on 2010.

Temporarily named ununseptium (Uus), the element is one of the heaviest element that we know of. 

(A Simplified electron cloud model of ununseptium: each dot represents an electron, and each number on the top right corner denotes the number of electrons in each "ring," starting from the inner-most one)

The team responsible for the element had smashed isotopes of calcium and radioactive berkelium in a particle accelerator, in order to create a mere 6 atoms of Element 117 (which lasted for a fraction of a second), marking the first recorded "discovery" of ununseptium as The New York Times had labeled it. Yet is it truly a discovery?

As we defined previously, a discovery involves "unknown" materials. Although some specific details of the element had not been known, at least the general possibility of the concept had been known since the creation of the periodic table. For example, we knew that a theoretical Element 117 would have 117 protons. Moreover, this element had not been "found" like how other elements such as oxygen had been found (for instance, this was not found in a "natural surrounding"). But most importantly, the team that created the element had planned and used specific procedures to form the element that did not exist beforehand. This directly correlates to the definition of "create."

Therefore, we can see that artificially synthesized elements such as Uus are more results of creation than discovery; yet nonetheless other "naturally occurring" elements are results of discovery than creation. It is very perplexing to see that even in the realm of the basic building blocks of chemistry-- the world of elements-- the conflicting distinctions between discovery and creation is evident. 

On a last note, Dr. Kenton Moody, a member of the team that created Uus, declared that,

The question we’re trying to answer is, ‘Does the periodic table come to an end, and if so, where does it end?’

His question reveals yet another in response, which we will leave as an open question for now: Is there a limit to such achievements of creation, or are we bounded by the things we can discover?

Before We Start

So obviously, the question posted earlier (whether chemistry is discovered or created) is much more complicated than a simple yes or no question. To even begin to answer this, we need to explore and sort through numerous branches of chemistry-- both deeply and carefully. But first, and perhaps most importantly, we need to clarify what we specifically mean when we say that something is "created" or "destroyed."  

In general, dictionary.com provides the following definitions:

Discover: gain sight or knowledge of (something previously unseen or unknown)

Create: to cause to come into being, as something unique that would not naturally evolve or that is not made by ordinary processes.

Basically, the distinction lies in the fact that creation revolves around the formation of previously nonexistent materials or ideas by humans and our invented "processes," while discovery relies more broadly on finding unknown substances or concepts. We will discuss the context of chemistry around these definitions, at least for now.


Just as importantly, we need to establish why this distinction even matters, in a practical sense. You might be asking yourself, "Does the difference significantly and tangibly affect applications of chemistry in our world?" And the answer is yes, beyond doubt.

The ethical dilemmas that the question of discovery or creation can prove to be vital in the realm of chemistry. By differentiating and classifying different aspects of chemistry under the two categories, we protect ourselves from the arrogant delusions that humans are the creators and the centers of the world (which result in major blockades to scientific advancements); we must prevent the scene that philosopher Immanuel Kant described as the current, disappointing actions of humankind: "Our intellect does not draw its laws from nature but imposes its laws upon nature." At the same time, we realize through such discussions the purpose of chemistry-- to study the "discovered" and balance them with our own "creations" in order to behoove the welfare of all life. 

With this in mind, we begin our journey on the synthesis of symmetry-- discovered or created 

Opening Post

Hello, welcome to our blog!

In this blog, we will be addressing a variety of topics regarding the synthesis of symmetric molecules, ranging from the process of forming these molecules to their practical applications. Ethical considerations throughout each process will also be discussed.

In addition, we will also be addressing a key topic, which we'll leave as an open question for now:

Is chemistry discovered or created?