Dankeschön or danke schön?

[dense plover]

I just recently communicate to German exchange students in my uni, and somehow they responded to my messages with "Dankeschön" instead of "danke schön" I've googled that Dankeschön is the nomen form, but is it actually correct to respond it that way for thanking someone?

[humble minnow]

No, the noun is not correct in that situation. However, do note that even though it's "danke schön", the spelling "dankeschön" for the response is very common, even though it's basically a "common mistake" rather than official alternative spelling (at least as far as I know).