The most common and most likely answer to this crossword clue is the 9 letter word NONMETALS
N
O
N
M
E
T
A
L
S
Buddy explains!
The straight part
We know that "He & I" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case he & i = nonmetals.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does NONMETALS mean?
NONMETALS noun- An element, such as phosphorus or chlorine, that does not have the chemical or physical properties of a metal.