Thanks to the Chinese Breeze books I'm learning what 氰化物 means. Not that I expect to use it anytime soon...

The Chinese Breeze reader plus a few dictionaries I've checked show it as qing2hua4wu4, Skritter has qing1hua4wu4.

(Let me know if there's a more appropriate place to flag issues with particular words.)

Skritter is right on this one. On Pleco my various dictionaries have 氢 as a first tone. And the one dictionary that has the word Hydride has the same tone combination as Skritter.

http://xh.5156edu.com/html3/12636.html

Above online dictionary that calls itself an online Xinhua dictionary has it as second tone, Taiwanese Chinese dictionary below has it as first. A couple of other mainland sources had it as second tone.

http://dict.revised.moe.edu.tw/cgi-bin/newDict/dict.sh?cond=%D9%E6&pieceLen=50&fld=1&cat=&ukey=1824326435&serial=1&recNo=1&op=f&imgFont=1

Are the following two getting mixed up?

氢化物[氫--]
qīnghuàwù
(NOUN) hydride

氰化物
qínghuàwù
(NOUN) cyanide

Which Chinese Breeze reader was it in, please?

Hi all - this was in the Level 1 reader “错，错，错！”

They list it as 氰化物 qínghuàwù

The dictionaries I checked that showed it that way were:
Pleco - ABC and CC dictionaries
nciku.com
iCED iOS app - ABC and CC dictionaries
mdbg.net

Not sure about nciku, but I guess all of those are really just checking CC-CEDICT and the ABC dictionary (which is a Taiwanese company right?)

But I did find that in the print 2nd edition of the Oxford Concise English-Chinese dictionary it was shown as qīnghuàwù.

I'm not really at a level yet where I can refer to Chinese language dictionaries to track down the etymology of this stuff.

Seems like 氰 looked up on its own will show both 1st and 2nd tones.

Ah, I actually read that one, but I didn't think much about the cyanide.
I can only find it in one Pleco dictionary (ABC), and that has first tone - other dictionaries on Pleco have at least the qíng, first tone again, but one has both first and second.

So, sorry if this is obvious but is there some place where I can officially submit a proposed correction? Somewhat new to all this on Skritter.

Other cyanide-related compounds, looked up in Skritter, have 氰 as 2nd tone (e.g. 氰化). That combined with how it's listed in the Chinese Breeze book and the various dictionary entries make me suspect it should be changed in this case.

I'm not totally sure, but I've taken your suggestion and changed it to second tone here. You can bring up a correction anywhere and we'll see it, although if you see it during practice, it's easiest to just submit it there.