Sciencemadness Discussion Board

The logic behind symbols of chemical elements ?

metalresearcher - 11-10-2023 at 08:21

That is what always wondered me. The symbols have either one uppercase letter (e.g. B, C, N) or one uppercase and one lowercase letter (Be, Ca, Ni). One can assume that single letter elements are more common, but that is not always the case, e.g. U and W are not that common. And why does a relative common element, like argon gas not just have a single 'A' or Lithium a single 'L' ?

And some names are also weird: yt-t-erbium are three elements in a single name. Lack of fantasy or creativity when the rare earths were discovered ? Sodium and Potassium not having the symbols So and Ps ? Probably due to the alternative names as Natrium and Kalium. Same applies to Tungsten which is a W(olfram) and not a 'T'.
I think it is all about history. Most chemical engineering was developed in the 19th and 20th century and we cannot change names or symbols anymore.
This is an interesting article on the history of symbols.

And what I also consider as weird is that single letter symbols are used for other hydrogen isotopes (D and T), but not for other elements.

And also the same two letter format for some compounds, e.g Me = methyl, Et = ethyl, Ac = acetate (or actinium ?) and not e.g. three letters to avoid confusion with real elements ?.

Are the IUPAC really logical ?

Cathoderay - 11-10-2023 at 09:23

That Wikipedia article is a very condensed history which doesn't do it justice.
Naming of the elements began at least as far back as the 1700s.
Of course at one time there were only four elements, Earth, Fire, Air and Water!
The names originated from many sources, some ancient ones based on the minerals they were found in, later many were suggested by the person that first discovered them. Lately it was more of a committee choice. Different people, different countries, different times.
The symbols are not very logical because they were developed through many years, not all at once, by many people in many places. It is very difficult to get people from many countries to agree on anything.
An interesting popular book that goes into some chemical history, (as well as some interesting stories from the author's boyhood) is "Uncle Tungsten" by Oliver Sachs.

averageaussie - 11-10-2023 at 14:12

regarding ytterbium, terbium, erbium and yttrium are named after the town they were discovered in, ytterby in sweden.

for the hydrogen isotopes, deuterium and tritium have the largest differences in isotopic effects.

the two letter format for compounds very rarely causes confusion, they are most often used in organic chemistry and there are very few overlaps.

j_sum1 - 11-10-2023 at 18:06

Element names and symbols have developed over a long period of time. Similar to most other scientific nomenclature systems.
They begin out of a desire to classify and solve current problems. They develop more fully as new science is discovered and systems emerge to guide the classification.
I would not expect any underlying logic to element names simply because the history extends over a long period and numerous cultures, discoverers and scientific disciplines. I do expect to see certain systems of logic overlaid onto the nomenclature (IUPAC naming rules) as the field has matured.

(I still think J for Nihonium and Q for Quercine instead of Tennessine would have been cool. But then, I did not get a say.)

clearly_not_atara - 11-10-2023 at 19:11

It's all the Germans' fault.

BromicAcid - 11-10-2023 at 19:31

It's not logic so much as history. Early elements soaked up many of the single letter abbreviations and as things grew the two letter abbreviations became the norm. Some of the single letter abbreviations are taken up by other branches of the sciences as you mentioned such as T for tritium, D for deuterium, Ph for phenyl, limiting the options further. Look at origins for things like tungsten (wolfram in German) or Sodium (natrium in Latin). The interesting thing to me is reading through older chemistry texts when certain elements were just coming out like Niobium making its debut as Columbia (symbol Cb but later changed to Nb). Since these all started out as shorthand at one time there wasn't total consensus on what symbols represented which element, and some countries used their own sets of symbols. I remember reading through a paper on methyl iodide published around the turn of the last century that represented it as MeJ, where J is for Jodid (German for Iodide).

[Edited on 10/12/2023 by BromicAcid]

DraconicAcid - 11-10-2023 at 20:05

Quote: Originally posted by BromicAcid  
I remember reading through a paper on methyl iodide published around the turn of the last century that represented it as MeJ, where J is for Jodid (German for Iodide).

I'm pretty sure that J is for Jod, anion or not.

Tsjerk - 11-10-2023 at 20:35

Well, the periodic table is an universal system, not an English one.

[Edited on 12-10-2023 by Tsjerk]

Texium - 11-10-2023 at 20:38

Quote: Originally posted by metalresearcher  
And also the same two letter format for some compounds, e.g Me = methyl, Et = ethyl, Ac = acetate (or actinium ?) and not e.g. three letters to avoid confusion with real elements ?.
It is hardly ever confused. Ac (which to be clear, is acetyl, not acetate, as people on this forum frequently misuse it: acetate is OAc) is ubiquitous in organic chemistry. Actinium is rarely seen at all, especially in organic chemistry, and if it was, context would make it obvious which it is since a trivalent metal ion has a very different bonding pattern than an organic functional group. Even if I said Ac(OAc)3 it looks weird, but it’s pretty clear I mean actinium acetate, since acetyl triacetate would be an incredibly impossible molecule! That’s the only one that could even stand any chance of being confused. The only other functional group abbreviation that is shared with an element is Ts for tosyl/tennessine, and the use of it for tosyl far predates discovery of the element! I think they should have used Tn for tennessine, but oh well. Maybe they thought it looked too much like “tin.”

Why not use 3 letters? We do, sometimes: Boc, Cbz, and TMS are common ones. But generally two letter abbreviations are less clunky and they just look better, so nobody is itching to change them! I think it also points to different perspectives from different branches of chemistry of what is significant and important to represent in a concise manner. You might suggest that the elements, as the fundamental building blocks of chemistry, should always have precedence, while functional groups, that are in a sense, human constructs, should defer to them and settle for clunkier abbreviations. As an organic chemist, though, I use Ac as an abbreviation for acetyl literally every day, but I hardly ever even think about actinium, so I’m not going to use Ace or whatever instead just because of some weird edge case that I’ll probably never encounter.

Don’t even get me started on amino acid single letter codes- they use letters including C, F, H, I, K, P, V, W, and Y, and some of them don’t even contain the letter anywhere in the name! (looking at you, twyptophan) Nonetheless, there are good reasons for them to be used too, even if it is incredibly confusing when you first see them.