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How do i? Easily insert chemical symbols with subscripts (iPad/iPhone)

Joined
3 Jan 2016
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383
Location
Woking, UK
I have just worked out how to improve the readability and geeky accuracy of my posts when referring to NH₃/NH₄⁺, CO₂, NO₂⁻, NO₃⁻, O₂, etc etc. It's easy!

Most of the time I'm posting from an iPad, so that's where I've solved the problem. It would also work on an iPhone. I dare say Android devices might have similar functionality - and if not, why not?!

Firstly, to gain access to the little subscript and superscript characters, you need to download an app that allows you to insert Unicode characters. It isn't important what "Unicode" is; it's simply the numeric code that modern computer systems use to encode the myriad of characters and symbols used in text. The app I downloaded is free, and is simply called "Unicode Free".

From the app, you can tap on one of the categories on the left-hand side to select just the subset of characters that you're interested in (otherwise there would be thousands to wade through). So for our purposes you want "Superscripts, subscripts and marks". The right-hand side of the screen shows a pretty comprehensive table of characters. You can fairly easily find the subscript "2", "3", etc, as well as the superscript plus and minus. Tapping any of them brings up a dialog box with further information about the character, and it also has a "copy" command on it that copies the character to the clipboard - you can then paste it anywhere you want it.

But doing it that way every time would be horribly tedious, so there's a second part of my suggestion that makes it fully automatic. Once you've learnt how to copy and paste the special characters from "Unicode Free", you can set up a bunch of keyboard shortcuts that will automagically insert the correctly formatted chemical formulae for you. Go into Settings, then General, then Keyboard, then Text Replacement. Here you can define shortcuts that get automatically replaced by more complex things. Tap the "+" in the top-right corner to add a new one, and type "nh3" into the box labelled "Shortcut". Into the box labelled "Phrase", type "NH" in capitals, and then paste the subscript "3". Then tap "Save" in the top-right corner.

Now, whenever you type "nh3" anywhere on your iPad/iPhone, it will suggest "NH₃" as a replacement. If you simply carry on typing it will perform the replacement automatically, but you can override the replacement in the usual way if you don't want it (as I have done several times while typing this post). The shortcut is case-insensitive, so it will work even if you type "Nh3".

Obviously you can repeat the above instructions to add all the other chemical formulae, and you can include the superscript plus and minus if you want. You only have to set it up once on each device, and it should work in every app.
 
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So far I've set up these shortcuts:

caco3 ➝ CaCO₃
co2 ➝ CO₂
kh2po4 ➝ KH₂PO₄
kno3 ➝ KNO₃
nh3 ➝ NH₃
nh4 ➝ NH₄⁺
no2 ➝ NO₂⁻
no3 ➝ NO₃⁻
o2 ➝ O₂
po4 ➝ PO₄³⁻

And if you don't want to download "Unicode Free", you could simply copy and paste the chemical formulae from this post!
 
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