When was the symbol for potassium changed from Ka to K?

Question

Wikipedia says that Ka was a symbol for potassium once.

Current symbol is K.

Name changed due to a standardization of, modernization of, or update to older formerly-used symbol.

When was the symbol for potassium changed from Ka to K? What was the rationale behind that?

Some findings. The INTERNET Database of Periodic Tables's first image with a symbol for potassium is of Charles Daubeny's system using K in 1831. Surprisingly I could not find any use of Ka. But there are many German-speaking books using Ka in the late 19th century, as well as some English ones. More recent findings of Ka: 1894, 1943, 2013

We already had a very competent answer to a similar question here. http://chemistry.stackexchange.com/questions/42561/why-was-lawrenciums-symbol-changed — mhchem, Mar 09 '17 at 09:06
There are many German-speaking books using Ka in the later 19th century. English KaCl findings (because that makes a better search term): 1894, 1943, 2013! — mhchem, Mar 09 '17 at 10:53
If guessing is OK I assume it is to avoid confusion with Potassium K and subscript a, like in pKa. There was no "K" so then the change is simple and easy. — Stian, Mar 09 '17 at 11:20
@StianYttervik That was my guess also. But I need a definite answer (background for my question). — mhchem, Mar 09 '17 at 11:32
This is the original publication in which Jacob Berzelius first proposed the name "kalium" with the symbol "K" for potassium in 1814. Emphasis on proposed, I cannot yet find when this was accepted...we're getting there though! — airhuff, Mar 09 '17 at 19:04
I would speculate that Ka would be easily confused with K(alpha) and the "a" was therefore dropped . — A.K., Oct 15 '21 at 05:49

AChem · Answer 1 · 2021-10-14T20:57:03.283

The symbol for potassium was mostly K in the English speaking world and even some old German book use K (as early as 1829 search Kalium in this book). So there was no official change from Ka to K, because both symbols were concurrently used in various parts of the world, just one symbol, Ka, wiped out of fashion. Perhaps the German logic was to retain (Ka)lium and (Na)trium. It is even interesting to see Ka and K being used in the same paper by no other than Bunsen and Kirchoff (the discoverer of rubidium and cesium). For example,

And their beautiful spectra, note Ka on the left. Available for free from Taylor and Francis or use Google Scholar. G*. Kirchhoff & R. Bunsen (1861) XLII. Chemical analysis by spectrum observations.— Second memoir , The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 22:148, 329-349, DOI: 10.1080/14786446108643164*

Humphrey Davy did not propose a symbol for sodium or potassium (from soda ash and potash, in 1807) because he was not 100% sure if they were elements. He implied that even if someone later shows that they are elements, the names can be retained as elements obtained from those metals.

Google Scholar the DOI, and the first result is that paper. Sorry, it is from Taylor & Francis. — AChem, Oct 14 '21 at 20:55
Neither https://doi.org/10.1080/14786446108643164 nor https://doi.org/10.1039/QJ8611300270 are freely accessible for me. — mhchem, Oct 15 '21 at 21:10
If you really want to read this article, request a friend from a university. For some reasons, I could see pdf option in Google Scholar. — AChem, Oct 15 '21 at 21:27

When was the symbol for potassium changed from Ka to K?

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