It looks like the author's first language may be Dutch, where carbon monoxide is "koolmonoxid" and "kool" can mean both "coal" and "carbon" (although there are more specific words for coal such as "steenkool" = "stone carbon").

Same in most Germanic/Scandinavian languages I believe. Carbon and Coal are synonymous.

Coal as in coal power, coal barbecue, and the element carbon use the same word. That’s not a coincidence.

Apart from some exotic forms like diamonds, trees or rabbits (less pure), coal is how we normally encounter carbon.

In German "Kohle" means coal, and "Kohlenstoff" is carbon. It's not the same word.

(But carbon monoxide is "Kohlenmonoxid")

But "Kohlenstoffmonoxid" is the actual correct term. https://de.wikipedia.org/wiki/Kohlenstoffmonoxid

"Kullos" = "coal fumes" is a term for carbon monoxide in Norwegian.

>Apart from some exotic forms like diamonds, trees or rabbits (less pure), coal is how we normally encounter carbon.

Also graphite. But yeah, coal is basically the purest form of carbon in common bulk usage.

The same in Polish, which is a Slavic language - Carbon Monoxide is "Tlenek Węgla" - and "Węgiel" literally means coal.

Same in Czech. "Kyslicnik uhlicity", and "uhli" means coal (plural).

In Russian, Carbon is "Uglerod", whereas coal is "Ugle". CO, when not referred to by its colloquial name, would be "Uglekislorod" - literally, Coal-oxide.