The wiki page states that "Splitting harmonium through distillation will give something different from atium and lerasium." But the WoB it cites (pasted below)
Questioner
If I was to take harmonium and separate it out through distillation, would I get lerasium and atium or something that functions similarly?
Brandon Sanderson
No, you would-- It actually has become a different--
Questioner
Can't be split?
Brandon Sanderson
Yeah. I mean, you could find a way, but you're not going to get it through normal, mechanical means.
It seems Brandon is saying that Harmonium is a pure metal and not an alloy and thus distilling it wont split it into anything. This contradicts the info on the wiki.
Skyward Houston signing (Nov. 19, 2018)