Crossword Genius

Element nitrogen is missing from compound number 1 (6)

Ross

I believe the answer is:

erbium

'element' is the definition.
(erbium is a chemical element)

I don't understand the remainder of the clue.

(Another definition for erbium that I've seen is " Metal element with atomic number 68".)

I've seen this clue in the Independent.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.