How Many Chemical Compounds Exist?

The universe is filled with billions of chemicals, each representing a tiny pinprick of potential. And we have only identified 1% of them. Scientists believe that undiscovered chemical compounds could assist to reduce greenhouse gas emissions or spark a medicinal breakthrough similar to penicillin.

But first, let’s be clear: chemists are interested. Since Russian chemist Dmitri Mendeleev created the periodic table of elements in 1869, which is essentially a chemist’s Lego set, scientists have been discovering the chemicals that helped shape the contemporary world. We needed nuclear fusion (firing atoms at each other at the speed of light) to create the final few elements. In 2010, this method was used to synthesize element 117, tennessine. 

However, in order to understand the entire extent of the chemical cosmos, you must also understand chemical components. Some occur naturally; for example, water is made up of hydrogen and oxygen. Others, like as nylon, were developed in lab tests and are now produced in factories.

Elements are made up of one sort of atom, while atoms are made up of even smaller particles such as electrons and protons. All chemical compounds consist of two or more atoms. Although it is possible that there are still undiscovered elements to locate, this is doubtful. So, how many chemical compounds can we create with the 118 distinct types of element Lego pieces we now have?

Large Numbers

We can begin by preparing all of the two-atom compounds. There are many of these: N2 (nitrogen) and O2 (oxygen) combined account for 99% of our air. It would probably take a chemist around a year to create one compound, and there are 6,903 two-atom compounds in principle. So there’s a town of chemists working all year to create every feasible two-atom molecule.

There are approximately 1.6 million three-atom compounds such as H₂0 (water) and C0₂ (carbon dioxide), equivalent to the combined population of Birmingham and Edinburgh. Once we reach four- and five-atom molecules, everyone on Earth would have to produce three compounds each. And to generate all these chemical compounds, we’d have to recycle all of the materials in the universe multiple times.

However, this is an oversimplification. Compound structure and stability can make synthesis more complex and difficult.

The largest chemical compound to date was created in 2009 and has approximately 3 million atoms. We don’t know what it accomplishes yet, but similar molecules are used to keep cancer medications in the body until they reach the correct location.

Also read : Common Chemical Compounds Used in Everyday Life

Chemistry Has It’s Law

Surely, not all of those chemicals are feasible.

Yes, there are laws, but they are rather flexible, which opens up additional options for chemical compounds.

Even the solitary “noble gases” (neon, argon, xenon, and helium), which rarely bond to anything, can form compounds. Argon hydride (ArH+) does not occur naturally on Earth but has been discovered in space. Scientists have been able to create synthetic versions in laboratories that simulate deep space conditions. So, when you incorporate harsh settings in your computations, the number of potential molecules grows. 

Carbon prefers to be connected to one to four other atoms, however five is feasible on rare occasions and for brief periods of time. Consider a bus with a maximum capacity of four. The bus is at the stop, and passengers are getting on and off; during this time, there may be more than four individuals on the bus.

Some scientists spend their entire lives trying to create molecules that, according to the chemistry rules, should not exist. Sometimes they succeed.

Another topic scientists must consider is if the desired molecule can only live in space or severe settings, such as the high heat and pressure found at hydrothermal vents, which are similar to geysers but located on the ocean floor.

How Scientists Look for New Compound

Often, the solution is to look for molecules that are similar to those that are currently recognized. There are two major approaches to accomplish this. One method involves modifying a known substance by adding, removing, or swapping some atoms. Another approach is to use fresh starting materials in a previously recognized chemical reaction. This occurs when the method of creation remains consistent yet the products differ significantly. Both of these strategies involve searching for known unknowns.

Returning to Lego, it’s like building a house, then a slightly different house, or purchasing new bricks and adding a second story. Many scientists spend their careers exploring one of these chemical houses.

But How Would We Look for a Brand New Compound?

Chemists can learn about novel substances by observing nature. Penicillin was discovered in 1928 when Alexander Fleming noticed that mould in his petri dishes inhibited bacterial growth.

Over a decade later, in 1939, Howard Florey discovered how to make penicillin in meaningful quantities, still using mould. However, it took Dorothy Crowfoot Hodgkin until 1945 to establish the chemical structure of penicillin.

That is significant because a portion of penicillin’s structure has atoms arranged in a square, which is an uncommon chemical arrangement that few chemists would expect and is difficult to create. Understanding penicillin’s structure allowed us to identify its appearance and search for chemical cousins. If you are allergic to penicillin and require an alternate antibiotic, you can thank Crowfoot Hodgkin.

Nowadays, it is much easier to determine the structure of novel molecules. Crowfoot Hodgkin created the X-ray technology that she used to discover the structure of penicillin, and it is now used to analyze compounds around the world. And the same MRI approach used in hospitals to identify disease may be applied to chemical molecules to determine their structure.

But even if a chemist predicted an entirely new structure unconnected to any molecule known on Earth, they would still have to create it, which is the difficult part. Knowing that a chemical compound exists does not tell you anything about its structure or the conditions required to produce it.

Many important chemicals, such as penicillin, are easier and cheaper to “grow” and extract from molds, plants, or insects. Thus, scientists looking for new chemistry continue to hunt for inspiration in the smallest corners of the environment around us.