Why haven't chemists created a periodic table of compounds?

A Periodic Table of compounds?

• There are over 20 million known compounds. yeah, thats reason enough.

• One major reason I can think of, that hasn't been addressed yet, is the periodicity of the elements. You can line the elements up into neat functional groups--alkali metals, transition elements, halogens and so on. This you couldn't do with compounds, even if you had a separate table for hydrocarbons, one for elastomers, one for dyestuffs... Compounds also find wide use as smaller blocks of larger compounds. We call these precursors. Take toluene. It's a very toxic compound, but if you compound it into toluene diisocyanate, then compound that into polyurethane, it becomes safe enough that you can build it into replacement hip joints. Chemists do keep books of compounds, but a table on a big sheet of paper the size of...oh, the entire side of a Wal-Mart store might be big enough? It could never happen.
  

• This would be an impossible task/table as there are literally tens of millions of compounds, and new compounds are being created or developed all the time. For an idea of how many compounds there are, have a look at an Aldrich catalogue, which you'll find in most labs.
  

• Also, probably for the same reason multiplication tables don't include every combination. Once you know the basic ones, you can fairly easily calculate the rest. It is assumed that you can infer the atomic weights, etc. from the combinations of two or more elements. It's not always exact, but probably close enough.

• Why should there be a periodic table of compounds? People used to have no idea how chemicals worked. Then they got an inkling that everything may be made of atoms. They then began to study elements (types of atoms) by experimenting on the elements themselves, and on their compounds. It was only then, in the 19th century I think, that people like Mendeleyev spotted patterns in the way the elements acted and reacted. This must have come as a surprise! In fact it was probably resisted by some people, as most big discoveries are. We had no reason to expect such a pattern relating the physical and chemical properties of elements to their atomic masses. We had no idea what atoms are made of. Today, of course, we know why this pattern exists (electron shells and all that). In fact, we now have a pretty good understanding of how chemistry works. If there had been some nice table we could put all compounds into, we would have put one together by now.

• The periodic table is nicely organized. Creating a table for compounds would be very hard to have this same organization. Elements are the foundation for compounds. Understanding how the elements work (or I might add how the atoms, electrons, protons, and type of the element works) is the main reason how compounds are created. Therefore, studying all fields of chemistry (general chemistry and organic chemistry would be a good start) will help improve this knowledge. Listing numerous amounts of compounds is ridiculous if someone already knows how the elements act. There's just no need to!

First answer by ID1420595056. Last edit by Rasip. Contributor trust: 3 [recommend contributor]. Question popularity: 66 [recommend question]