| Io - Isn | Nummer |
| Iod | 14 / selten stark 18 / # 21 Haut |
| Iodacetamid | 18 |
| 2-Iodbenzanilid | 16 |
| Iodbenzol | 14 / 18 |
| Iodbenzol-sulfonsäure-chlorid | 2 |
| Iodcyan | xxx |
| 5-Iod-2’-deoxyuridin | 14 / # (19a-c) |
| Iodessigsäure | 2 / 18 |
| Iodessigsäure-anhydrid | 14 / 2 / 18 |
| Iodessigsäure-Natriumsalz | 14 / 18 |
| Iodessigsäure-4-nitro-phenylester | |
| Iodethan | |
| Iodethanol | |
| 2-(2-Iodethyl)-prop-1,3-diyl-diacetat | 16 |
| Iodfenphos | 4 / 18 / 19 |
| Iodixanol | 14 / 19 |
| Iodmethan | 11 / 18 / 19 / 19a / # (19c) / # 21 Haut |
| 1-Iod-2-methyl-propan | 16 |
| Iod-mono-chlorid | xxx |
| Iodnitro-tetra-zolium-violett | xxx |
| Iodoform | 16 / 18 / 19 |
| 4-Iodo-2-[3-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-ureido- sulfonyl]-benzoesäure |
xxx |
| Iodo-sulfuron-methyl-natrium | 16 |
| Iodpenta-fluorid | 5 / 18 |
| Iodpentoxid | 14 / 2 / 18 |
| 2-Iodperfluor-propan | 5 / 18 |
| 2-(4-Iodphenyl)-3-(4-nitrophenyl)-5-phenyl-2H–tetra-zolium- chlorid |
16 |
| 1- / 2- Iodpropan | 16 / 18 |
| 3-Iodpropen | 2 / 18 |
| 3-Iod-2-propinyl-butyl-carbamat | 14 / 18 / 19 |
| 2-(3-Iodprop-2-yn-1-yloxy)-ethylphenyl-carbamat | 16 / 18 / # 6 Augen |
| Iodsäure | 2 / 18 / 19 |
| Iodthymol | 16 |
| Iodwasserstoff .... % | 2 / 11 / 18 / 19 |
| Iodwasserstoff, wasserfrei | 11 / 18 / 19 |
| Iodwasserstoffsäure | 2 / 11 / 18 / 19 |
| Iodylbenzol | 16 / 18 / 19 |
| Iohexol | 14 / 18 |
| Iopentol | |
| Ioxynil | 14 / 19 / # (19b) |
| Ioxynil-octanoat | 16 / 18 / # (19b) |
| Ipomoea tricolor | 14 |
| Ipomoea purga | 16 |
| Ipratropium-bromid | 14 |
| Iprobenphos | 16 |
| Iprodion | 14 / 18 / 19 / # (19a) |
| Iprovalicarb | 16 |
| Iridium | 12 |
| Iridium-chlorid | 16 / 18 |
| Iris pseudacorus | 14 |
| Iroko | 18 |
| Isatin | 16 |
| Isatosäure-anhydrid | 16 / 18 |
| Isazophos | 14 / 18 / 19 |
| I S D N | 16 / 13 |