Signifying sounds and structures

A comparison of chemical and musical notations

I’ve been looking for similarities between the ways we represent music and organic chemistry on paper. The answer is a stretch but the search was a pleasure.

First day first: in the same way pitches are represented by the position of note heads on the staff, you can draw a line, then go ahead and call that ethane. Organic chemistry and music both begin with fairly simple systems of nomenclature.

The air of competence this imparts on the learner is temporary, however. The dots stack and weave below, on, in between, and above the lines of the musical staff to yield complex chords and dense contrapuntal tapestries. In a similar way, the skeletal formulae representing bonded carbon atoms morph into compounds with names like Ethyl 1,2,3,4-tetrahydro-6-methyl-2-oxo-4-phenylpyrimidine-5-carboxylate.

In both organic chemistry and music, a simple series of symbols can bloom into something approaching impenetrable.

This is daunting, and probably really sucks when you’re trying to learn hard stuff. But it also creates the possibility for a particular type of elegance, rooted in restraint: that of striving for simplicity.

A 1980 entry in the Journal of Organic Chemistry, for example, described “A new, elegant route to a key intermediate” for the synthesis of some chemical. The principal virtue of the new mechanism was that it was a “more straightforward approach” to the intermediate species; the article takes up a page and a half. “Scheme I,” the only scheme, is five steps.

In music as well, simple is beautiful. Look at the chart for Miles Davis’ “Blue in Green” and listen to the head. Some of the loveliest pop music is also basic on paper. “Get Back” by the Beatles strikes me as one example.

On another note, musical and organic chemistry symbols help us to get a handle on topics that are difficult for the human brain to comprehend.

Fundamentally, the sounds that make up music are waves of pressure moving through air over time. Music notation allows us to make sense of it in a visual way so that we can better grasp it, control it, and explore its patterns.

In This is Your Brain on Music, Daniel Levitin points out that “pitch is a purely psychological construct”; “loudness is a purely psychological construct”; “reverberation refers to [ . . . ] perception”; and “meter is created by our brains.” When we write it down, we can keep a record of the changes in these components as if they were primary qualities, inherent in the propagating waves.

Organic chemistry notation similarly helps us work with a difficult concept. In one sense, organic chemistry is electron densities getting close to each other and reconfiguring themselves. At that level, just like with the pressure waves in music, the concept of being able to “see” what is going on breaks down. If you could shrink yourself to 1 angstrom, no one actually believes you would witness a bunch of hexagons skittering around. We represent it this way, though, and it is close enough that we can reliably predict how the real thing will behave.

There are many other features that organic chemistry notation and musical notation have in common, such as moments of symmetry, and a tendency towards making frequent use of certain motifs. The fact of the matter is that most of the similarities discussed above also exist in other sets of symbols, for example those used in mathematics and everyday language.

This of course weakens the force of the argument that organic chemistry and musical notation have something special in common. But there is a potential upside. People should recognize that many of the interesting qualities of their chosen field are shared with another discipline, even when they do not seem connected.

Hopefully, chemists will check out music, musicians will explore math, and mathematicians will become interested in linguistics. News writers should stick to what they know.