| 1,6-heptadiyne | heptadiyne | C7H8 | C 1s | hz-0cckk.os | HS90 |
| hexachlorodisilane | hexachlorodisilane | Cl6Si2 | Cl 2p | sc-0cll3.os | W92 |
| hexachlorodisilane | hexachlorodisilane | Cl6Si2 | Si 2p | sc-0sil3.os | W92 |
| 2,4-hexadyne | hexadyne | C6H6 | C 1s | hv-0cckk.os | HS90 |
| Hexafluorobenzene | hexafluorobenzene | C6F6 | C 1s | hf-0cckk.os | HF&87 |
| Hexafluorobenzene | hexafluorobenzene | C6F6 | F 1s | hf-0ffkk.os | HF&87 |
| 1,3- Hexafluorobutadiene | hexafluorobutadiene | C4F6 | C 1s | fb-0cckk.os | RI&88 |
| 1,3- Hexafluorobutadiene | hexafluorobutadiene | C4F6 | F 1s | fb-0ffkk.os | RI&88 |
| Hexafluoroethane | hexafluoroethane | C2F6 | C 1s | fe-0cckk.os | RI&88 |
| Hexafluoroethane | hexafluoroethane | C2F6 | F 1s | fe-0ffkk.os | IM&88 |
| hexamethyl disiloxane | hexamethyl disiloxane | C6H18OSi2 | C 1s | ss-0cckk.os | UT+97 |
| hexamethyl disiloxane | hexamethyl disiloxane | C6H18OSi2 | O 1s | ss-0ookk.os | UT+97 |
| hexamethyl disiloxane | hexamethyl disiloxane | C6H18OSi2 | Si 2p | ss-0sill.os | UT+97 |
| hexamethyldisilane | hexamethyldisilane | C6H18Si2 | C 1s | si-0cckk.os | W92 |
| hexamethyldisilane | hexamethyldisilane | C6H18Si2 | Si 2p | si-0sil3.os | W92 |
| n-Hexane | hexane | C6H14 | C 1s | nh-0cckk.os | HI87 |
| Hexaphenyldisilane | hexaphenyldisilane | C36H30Si2 | C1s | a1-0cckk.os | HH13 |
| Hexaphenyldisilane | hexaphenyldisilane | C36H30Si2 | C1s | a1-0sill.os | HH13 |
| Hexaphenyldisilane | hexaphenyldisilane | C36H30Si2 | C1s | a1-1cckk.os | HH13 |
| Hexaphenyldisilane | hexaphenyldisilane | C36H30Si2 | Si 2p | a1-1sill.os | HH13 |
| 4-HEXEN-3-ONE | hexen-3-one | C6H10O | C1s | ke-0cckk.os | LUH99 |
| 4-HEXEN-3-ONE | hexen-3-one | C6H10O | O1s | ke-0ookk.os | LUH99 |
| N-Hexylpyruvamide | hexylpyruvamide | C1s | pz-0cckk.os | UP |
| 3-Hx-thiophene | hx-thiophene | C10H17S | C 1s | sh-0cckk.os | HT&90 |
| 3-Hx-thiophene | hx-thiophene | C10H17S | S 2p | sh-0ssl3.os | HT&90 |
| Hydrazine | hydrazine | H4N2 | N 1s | hn-0nnkk.os | H90a |
| Hydrogen peroxide | hydrogen peroxide | H2O2 | O 1s | hp-0ookk.os | RH91 |
| Hydroquinone | hydroquinone | C6H6O2 | C 1s | qh-0cckk.os | FH92 |
| Hydroquinone | hydroquinone | C6H6O2 | O 1s | qh-0ookk.os | FH92 |
| Imidazole | imidazole | C3H4N2 | C 1s | iz-0cckk.os | AHG93 |
| Imidazole | imidazole | C3H4N2 | N 1s | iz-0nnkk.os | AHG93 |
| Iron | iron | Fe | Fe 2p,2s | aaa-fell.os | SF |
| Iron nonacarbonyl | iron nonacarbonyl | C9Fe2O9 | C 1s | fk-0cckk.os | RI&88 |
| Iron nonacarbonyl | iron nonacarbonyl | C9Fe2O9 | Fe 2p | fk-0fel3.os | RI&88 |
| Iron nonacarbonyl | iron nonacarbonyl | C9Fe2O9 | O 1s | fk-0ookk.os | WRH92 |
| Iron Pentacarbonyl | iron pentacarbonyl | C5FeO5 | C 1s | fw-0cckk.os | RI&88 |
| Iron Pentacarbonyl | iron pentacarbonyl | C5FeO5 | Fe 2p | fw-0fel3.os | RI&88 |
| Iron Pentacarbonyl | iron pentacarbonyl | C5FeO5 | O 1s | fw-0ookk.os | RI&88 |
| Iron-phosphaborane | iron-phosphaborane | B5C17FeH22O2 | B 1s | bi-0bbkk.os | HLD91 |
| Iron-phosphaborane | iron-phosphaborane | B5C17FeH22O2 | C 1s | bi-0cckk.os | HLD91 |
| Iron-phosphaborane | iron-phosphaborane | B5C17FeH22O2 | Fe 2p | bi-0fell.os | HLD91 |
| iron-phthalocyanine | iron-phthalocyanine | C32H16N8Fe | C 1s | zf-0cckk.os | RSH93 |
| Isobutane | isobutane | C4H10 | C 1s | ib-0cckk.os | HI87 |
| Isopentane (i.e. 2-methylbutane) | isopentane (i.e. 2-methylbutane | C5H12 | C 1s | ip-0cckk.os | HI87 |
| Isopropanol | isopropanol | C3H8O | C1s | is-0cckk.os | HH13 |
| Isopropanol | isopropanol | C3H8O | C1s | is-0ookk.os | HH13 |
| isopropyl ether | isopropyl ether | C6H14O | C 1s | ie-0cckk.os | UH&95b |
| isopropyl ether | isopropyl ether | C6H14O | O 1s | ie-0ookk.os | UH&95b |
| lactic acid | lactic acid | C3H6O3 | 01s | la-0ookk.os | GC&03 |
| lactic acid | lactic acid | C3H6O3 | C1s | la-0cckk.os | GC&03 |