Portal talk:Chemistry

New tracking category for deprecated mhchem syntax

The <ce /> or <chem> allows to format chemical sum formulae as described in https://en.wikipedia.org/wiki/Help:Displaying_a_formula#Chemistry

Technically this command was based on the MathJax adoption of the mhchem LaTeX package. This package changed from version 2 to version 3 http://vesta.informatik.rwth-aachen.de/ftp/pub/mirror/ctan/macros/latex/contrib/mhchem/mhchem.pdf and the migration is difficult:

Migrating from version 3{...}does escape to text now,  not math.$...$does only escape to ‘font-correctedmath mode’—check the results. Additional spaces will be inserted: A$x\,$H2Oshouldbe changed to$x$ H2O. Appearance of bonds, radical dot,x, single-letter variables,-in subscripts etc.  slightly changed—check if this fits with your font, in particular yourtext font.  Check all complex subscripts and superscripts (more than just number or acharge). The arrow arguments are set with the same syntax as the\cecommand—use$...$or${...}$for math. Deprecated commands like\cf,,and‘and\hyphenand\cmathwere removed completely.\ceewas removed—just use\ce.

As a first step we introduced a new tracking category https://en.wikipedia.org/w/index.php?title=Category:Pages_that_use_a_deprecated_format_of_the_chem_tags&action=edit&redlink=1 which is availibe from today for new formulae. https://phabricator.wikimedia.org/T225030

Any feedback is apprechaiated.

--Physikerwelt (talk) 14:06, 6 June 2019 (UTC)

If a page contains the correct formula of sulfuric acid, <chem>H2SO4</chem> or of disulfuric acid, <chem>H2S2O7</chem>, it is listed in this category, although the formulas are correct. Variants of this would work, e.g.

${\ce {H2S2O_{n}}}$ ${\ce {H2S2O}}$ ${\ce {H2S2O1}}$ ${\ce {H2S2O2}}$ ${\ce {H2S2O3}}$ ${\ce {H2S2O4}}$ ${\ce {H2S2O6}}$ ${\ce {H2S2O8}}$ ${\ce {H2S2O9}}$ ${\ce {H2S2O10}}$ ${\ce {H2S2O11}}$ ${\ce {H2S2O12}}$ ${\ce {H2S2O13}}$ ${\ce {H2S2O14}}$ ${\ce {H2S2O15}}$ ${\ce {H2S2O16}}$ ${\ce {H2S2O17}}$ ${\ce {H2S2O18}}$ ${\ce {H2S2O19}}$ ${\ce {H2S2O20}}$ ${\ce {H2SO4 + H2O}}$

will not be included in the category. The most important one, sulfuric acid H2SO4, does not work.

<chem>A ->[\text{text above}][\text{text below}] B</chem> works as expected, giving ${\ce {A->[{\text{text above}}][{\text{text below}}]B}}$ without problems. However, any variant of that, like

<chem>A ->[\text{text above}][\text{text below}] BC</chem>,

<chem>A ->[\text{text bove}][\text{text below}] B</chem> or

<chem>A ->[\text{B}][\text{C}] D</chem>

<chem>A ->[\text{text above}] B</chem> will result in formulas that looks as expected, but which is also in the "deprecated"-category. It seems hard to find examples where the \text{} labelling (suggested here) of the arrow works without being listed as "deprecated". --Nick B. (talk) 06:20, 16 May 2020 (UTC)

Some entries are cached. That is why the second example with BC renderes different from B. Also I suspect H2SO4 is a caching issue. See https://en.wikipedia.org/wiki/User:Physikerwelt/H2SO4. This page would be tracked as well, or? --Physikerwelt (talk) 11:31, 18 May 2020 (UTC)

The new page with the H2SO4 chem formula is included in the tracking category. Is it possible to modify the criteria and/or the caching which cause a page with a correct formula to be included in the list? Nick B. (talk) 15:00, 21 May 2020 (UTC)

Another simple example is RnF2: a page with <chem>RnF2</chem> will be included in the deprecated_format list (<chem>RnF_2</chem> can be used to display RnF2 without that problem: ${\ce {RnF_2}}$) Why is such a simple and correct fomula listed there? Nick B. (talk) 13:46, 8 June 2020 (UTC)

Wrong entries in the list, questionable naming. Use?

Simple and correct formulas, e.g. ${\ce {H2SO4}}$, ${\ce {CO2}}$, ${\ce {RnF2}}$, ${\ce {O2+}}$, ${\ce {NaBr}}$, causes pages to be included in the list "deprecated format of the chem tags". This is highly misleading. Please make sure that a page with a correct formula is not listed in a Maintenance categroy which belongs to the "Category:Articles with math errors".

The name "Pages that use a deprecated format of the chem tags" is highly misleading. Most pages are included in this category because within the chem-tags, math-Symbols like \cdot oder \equiv are used. In my opinion, calling a combination of math symbols and chem tags as "deprecated format" is not appropriate. Please consider renaming the category, e.g. "Pages that use math symbols within chem tags" and please consider to remove the category from "Category:Articles with math errors" since this is not really a math error (or consider renaming this category as well).

In which cases is this category helpful at all? In many cases, the math symbols within the chem tags work in spite of the listing as "deprecated". There are cases where chem-Tags do not work well, e.g. whith italic text. However, the category is not helpful in finding the cases where switching to math is really necessary. Nick B. (talk) 14:38, 23 August 2022 (UTC)

Information request for chemical compounds and bots

Hi, I am a user of Wikipedia ita, for some time now we have been having a discussion and I think that here I could find some answers to our doubts.

We are thinking if there is a bot that deals with the insertion of chemical compound data (chemical-physical properties and H and P phrases) on wikidata. The doubt arose because the data reported on our pages are not always correct or taken from official sources and having the data on wikidata from which to draw would remove many problems from that point of view, in fact using a bot that keeps the data on updated wikidata and that verifies the data shown in the wikipedia pages, there would be no problems.

My question is if you know if there is such a bot or if it can be programmed, the benefit would be great for all the different wikipedia.

I hope for your answer. -Griot Matteo (talk) 07:03, 27 May 2020 (UTC)

Yep it will make a difference 👽👽👽👽 14:24, 11 February 2021 (UTC) — Preceding unsigned comment added by Inventor24 (talk • contribs)