Browse reference spectra from the USGS Spectral Library Version 7 and other curated sources. Each spectrum includes interactive plots, metadata, and downloadable data.
Have an unknown spectrum? Match it against this entire library with HQI similarity scoring — no install, no data leaves your machine.
Identify My SampleLearn more about how spectral matching works, HQI scoring, and building a personal reference library on the Spectral Library Search page.
| Formula | Modality | Category | Source | ||
|---|---|---|---|---|---|
| 3,4-DIHYDRO-2H-PYRAN | C5H8O | Mass Spec | Chemical | MassBank | |
| 3,4-DIHYDRO-6-HYDROXY-2,5,7,8-TETRAMETHYL-2-(2-BENZIMIDAZOLETHIO)ETHYL-2H-1-BENZOPYRAN | C22H26N2O2S | Mass Spec | Chemical | MassBank | |
| 3,4-DIHYDRO-6-HYDROXY-2-(2-(IMIDAZOL-1-YL)ETHYL)-2,5,7,8-TETRAMETHYL-2H-1-BENZOPYRAN | C18H24N2O2 | Mass Spec | Chemical | MassBank | |
| 3,4-DIHYDRO-7-HYDROXY-2-(2-HYDROXYETHYL)-6-HEXYL-2-METHYL-2H-1-BENZOPYRAN | C18H28O3 | Mass Spec | Chemical | MassBank | |
| 3,4-DIHYDROCOUMARIN | C9H8O2 | Mass Spec | Chemical | MassBank | |
| 3,4-DIHYDROXYBENZOIC ACID | C7H6O4 | Mass Spec | Chemical | MassBank | |
| 3,4-DIHYDROXYHYDROCINNAM1C AC1D-TRI-TMS | C18H34O4Si3 | Mass Spec | Chemical | MassBank | |
| 3,4-DIHYDROXYPHENYLETHAN-1,2-DIOL | C8H10O4 | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHOXYACETOPHENONE | C10H12O3 | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHOXYBENZOIC ACID | C9H10O4 | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHOXYBENZOIC ACID METHYL ESTER | C10H12O4 | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHOXYBENZOIC ACID TRIMETHYLSILYL ESTER | C12H18O4Si | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHOXYBENZYL ACETATE | C11H14O4 | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHOXYCINNAMIC ACID | C11H12O4 | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHYL-1,1-DI(PARA-TOLYL)-1-SILACYCLOPENT-3-ENE | C20H24Si | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHYL-1,1-DIPHENYL-1-SILACYCLOPENT-3-ENE | C18H20Si | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHYL-6-(2,5-DIMETHYLPHENYL)-6-PHENYL-1,1-BIS(TRIMETHYLSILYL)-1-SILACYCLOHEX-3-ENE | C27H42Si3 | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHYLANILINE | C8H11N | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHYLBENZENAMINE | C8H11N | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHYLBENZOIC ACID METHYL ESTER | C10H12O2 | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHYLBENZOIC ACID TRIMETHYLSILYL ESTER | C12H18O2Si | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHYLPHENOL | C8H10O | Mass Spec | Chemical | MassBank | |
| 3,4-DIMETHYLPYRIDINE | C7H9N | Mass Spec | Chemical | MassBank | |
| 3,4-Dehydroxy-3'-deoxycapsanthin | C40H54O | Mass Spec | Chemical | MassBank | |
| 3,4-Diaminotoluene | C7H10N2 | Mass Spec | Chemical | MassBank | |
| 3,4-Dichlorophenylurea | C7H6Cl2N2O | Mass Spec | Environmental | MassBank | |
| 3,4-Didehydrorhodopin | C40H56O | Mass Spec | Natural product | MassBank | |
| 3,4-Dihydrospheroidene | C41H62O | Mass Spec | Natural product | MassBank | |
| 3,4-Dihydrospirilloxanthin | C42H62O2 | Mass Spec | Natural product | MassBank | |
| 3,4-Dihydroxy-L-phenylalanine | C9H11NO4 | Mass Spec | Natural product | MassBank | |
| 3,4-Dihydroxymandelate | C8H8O5 | Mass Spec | Chemical | MassBank | |
| 3,4-Dihydroxyphenyl Acetic acid | C8H8O4 | Mass Spec | Natural product | MassBank | |
| 3,4-Dihydroxyphenylacetic acid | C8H8O4 | Mass Spec | Natural product | MassBank | |
| 3,4-EPOXY MENTHANE | C10H18O | Mass Spec | Chemical | MassBank | |
| 3,4-Epoxy-7-octene | C8H14O | Mass Spec | Natural product | MassBank | |
| 3,4-HEXANEDIONE | C6H10O2 | Mass Spec | Chemical | MassBank | |
| 3,4-METHYLENEDIOXYBENZALDEHYDE | C8H6O3 | Mass Spec | Chemical | MassBank | |
| 3,4-METHYLENEDIOXYBENZENEACETIC ACID | C9H8O4 | Mass Spec | Chemical | MassBank | |
| 3,4-METHYLENEDIOXYBENZENEACETONITRIL | C9H7NO2 | Mass Spec | Chemical | MassBank | |
| 3,4-METHYLENEDIOXYBENZENEMETHANOL | C8H8O3 | Mass Spec | Chemical | MassBank | |
| 3,4-METHYLENEDIOXYBENZYL PROPIONATE | C11H12O4 | Mass Spec | Chemical | MassBank | |
| 3,4-METHYLENEDIOXYCINNAMIC ACID | C10H8O4 | Mass Spec | Chemical | MassBank | |
| 3,4-METHYLENEDIOXYPHENYL VINYL KETONE | C10H8O3 | Mass Spec | Chemical | MassBank | |
| 3,4-METHYLENEDIOXYPHENYLACETIC ACID | C9H8O4 | Mass Spec | Chemical | MassBank | |
| 3,4-Methylenedioxy-N-ethylamphetamine | C12H17NO2 | Mass Spec | Pharmaceutical | MassBank | |
| 3,4-Methylenedioxy-N-ethylamphetamine (MDEA) | C12H17NO2 | Mass Spec | Environmental | MassBank | |
| 3,4-Methylenedioxy-N-methylamphetamine (MDMA) | C11H15NO2 | Mass Spec | Environmental | MassBank | |
| 3,4-Methylenedioxyamphetamine (MDA) | C10H13NO2 | Mass Spec | Environmental | MassBank | |
| 3,4-Methylenedioxymethamphetamine | C11H15NO2 | Mass Spec | Pharmaceutical | MassBank | |
| 3,4-TETRAMETHYLENEPYRAZOLE | C7H10N2 | Mass Spec | Chemical | MassBank |