The most common and most likely answer to this crossword clue is the 8 letter word ISOTOPES
I've seen this crossword clue in The Daily Telegraph
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S
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More clues leading to the result ISOTOPES
- One then drinks different forms from table
- Spies too involved making variant forms of arsenic?
- One appeal about drink that may be radioactive
- I call for help carrying most important electronic and nuclear materials
- I like that poet’s new elementary forms
- Elementary variants to posies after arrangement
- 18 Poet is so worried these may be radioactive
- Atomic elements presented in bizarre depositions without din
- Big shot regularly has drinks in different forms
Buddy explains!

The straight part
We know that "nuclear materials" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case nuclear materials = isotopes.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 ISOTOPES mean?
ISOTOPES noun- Any of two or more forms of an element where the atoms have the same number of protons, but a different number of neutrons within their nuclei. As a consequence, atoms of isotopes will have the same atomic number but a different mass number.