sulfoarsenide

The story

1. Latinsulpur
2. Latinsulfur
3. Latinsulphur
4. Anglo-Normansulfre
5. Middle Englishsulphur
6. Englishsulfur
7. Englishsulfo-
8. Proto-Indo-European*ǵʰelh₃-
9. Proto-Indo-European*ǵʰl̥h₃enyom
10. Proto-Indo-Iranian*ȷ́ʰr̥Hanyam
11. Proto-Iranian*jr̥Hanyam
12. Old Median*zaranyam
13. Old Median*kā
14. Old Median*zaraniyakā
15. Middle Persian*zarnīk
16. Classical Syriacܙܪܢܝܟܐ (zarnīḵā)
17. Arabicالزَرْنِيخ (az-zarnīḵ)
18. Medieval Greekἀρσενικόν (arsenikón)
19. Latinarsenicum
20. Middle Frencharsenic
21. Middle Englisharsenik
22. Englisharsenic
23. Proto-Indo-European*dʰeh₁-
24. Englisharsenide
25. English todaysulfoarsenide

From sulfo- + arsenide.