List of diatomic molecules and monatomic elements
A curated reference list of common elemental diatomic molecules and monatomic noble gases with formulas, categories, and source identifiers.
| Name | Formula | Classification | Basis | SMILES | PubChem CID |
|---|---|---|---|---|---|
| Hydrogen | H2 | Diatomic molecule | Elemental diatomic gas | [H][H] | 783 |
| Nitrogen | N2 | Diatomic molecule | Elemental diatomic gas | N#N | 947 |
| Oxygen | O2 | Diatomic molecule | Elemental diatomic gas | O=O | 977 |
| Fluorine | F2 | Diatomic molecule | Halogen diatomic molecule | FF | 24524 |
| Chlorine | Cl2 | Diatomic molecule | Halogen diatomic molecule | ClCl | 24526 |
| Bromine | Br2 | Diatomic molecule | Halogen diatomic molecule | BrBr | 24408 |
| Iodine | I2 | Diatomic molecule | Halogen diatomic molecule | II | 807 |
| Helium | He | Monatomic element | Noble gas | [He] | 23987 |
| Neon | Ne | Monatomic element | Noble gas | [Ne] | 23935 |
| Argon | Ar | Monatomic element | Noble gas | [Ar] | 23968 |
| Krypton | Kr | Monatomic element | Noble gas | [Kr] | 5416 |
| Xenon | Xe | Monatomic element | Noble gas | [Xe] | 23991 |
| Radon | Rn | Monatomic element | Noble gas | [Rn] | 24857 |
| Carbon Monoxide | CO | Diatomic molecule | Heteronuclear diatomic molecule | [C-]#[O+] | 281 |
| Nitric Oxide | NO | Diatomic molecule | Heteronuclear diatomic molecule | [N]=O | 145068 |
| Hydrogen Chloride | ClH | Diatomic molecule | Heteronuclear diatomic molecule | Cl | 313 |
| Hydrogen Fluoride | FH | Diatomic molecule | Heteronuclear diatomic molecule | F | 14917 |
| Hydrogen Bromide | BrH | Diatomic molecule | Heteronuclear diatomic molecule | Br | 260 |
| Hydrogen Iodide | HI | Diatomic molecule | Heteronuclear diatomic molecule | I | 24841 |
| Hydrogen Cyanide | CHN | Diatomic molecule | Heteronuclear diatomic molecule | C#N | 768 |
| Sodium Chloride | ClNa | Diatomic molecule | Heteronuclear diatomic molecule | [Na+].[Cl-] | 5234 |
| Potassium Chloride | ClK | Diatomic molecule | Heteronuclear diatomic molecule | [Cl-].[K+] | 4873 |
| Lithium Hydride | HLi | Diatomic molecule | Heteronuclear diatomic molecule | [H-].[Li+] | 62714 |
| Sodium Hydride | HNa | Diatomic molecule | Heteronuclear diatomic molecule | [H-].[Na+] | 24758 |
| Potassium Hydride | HK | Diatomic molecule | Heteronuclear diatomic molecule | [H-].[K+] | 82127 |
| Lithium Fluoride | FLi | Diatomic molecule | Heteronuclear diatomic molecule | [Li+].[F-] | 224478 |
| Sodium Fluoride | FNa | Diatomic molecule | Heteronuclear diatomic molecule | [F-].[Na+] | 5235 |
| Potassium Fluoride | FK | Diatomic molecule | Heteronuclear diatomic molecule | [F-].[K+] | 522689 |
| Lithium Chloride | ClLi | Diatomic molecule | Heteronuclear diatomic molecule | [Li+].[Cl-] | 433294 |
| Potassium Bromide | BrK | Diatomic molecule | Heteronuclear diatomic molecule | [K+].[Br-] | 253877 |
| Sodium Iodide | INa | Diatomic molecule | Heteronuclear diatomic molecule | [Na+].[I-] | 5238 |
| Silicon Monoxide | OSi | Diatomic molecule | Heteronuclear diatomic molecule | O=[Si] | 66241 |
| Sulfur Monoxide | OS | Diatomic molecule | Heteronuclear diatomic molecule | O=S | 114845 |
| Phosphorus Monoxide | OP | Diatomic molecule | Heteronuclear diatomic molecule | O=[P] | 6857426 |
| Aluminum Monoxide | AlO | Diatomic molecule | Heteronuclear diatomic molecule | O=[Al] | 142249 |
| Magnesium Oxide | MgO | Diatomic molecule | Heteronuclear diatomic molecule | O=[Mg] | 14792 |
| Calcium Oxide | CaO | Diatomic molecule | Heteronuclear diatomic molecule | O=[Ca] | 14778 |
| Boron Nitride | BN | Diatomic molecule | Heteronuclear diatomic molecule | B#N | 66227 |
| Carbon Monosulfide | CS | Diatomic molecule | Heteronuclear diatomic molecule | [C-]#[S+] | 108054 |
| Cyanogen | C2N2 | Diatomic molecule | Heteronuclear diatomic molecule | C(#N)C#N | 9999 |
| Dicarbon | C2H2 | Diatomic molecule | Heteronuclear diatomic molecule | C#C | 6326 |
| Boron Monoxide | BO | Diatomic molecule | Heteronuclear diatomic molecule | [B]=O | 6327189 |
| Chlorine Monoxide | Cl2O | Diatomic molecule | Heteronuclear diatomic molecule | O(Cl)Cl | 24646 |
| Nitrosyl Chloride | ClNO | Diatomic molecule | Heteronuclear diatomic molecule | N(=O)Cl | 17601 |
| Hydroxyl Radical | HO | Diatomic molecule | Heteronuclear diatomic molecule | [OH] | 157350 |
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Methodology
The starter list separates stable elemental diatomic molecules from monatomic noble gases. PubChem supplies compound identifiers where available, while NIST is cited for reference data on selected diatomic species.
Expansion plan
The expanded dataset should add radicals, ions, isotopologues, and transient diatomic species as separate filtered views so the basic educational list remains readable.
Sources
PubChem
Canonical compound identifiers, names, formulas, structures, SMILES, and downloadable compound records.
NIST Chemistry WebBook
Reference physical chemistry data and diatomic constants for selected species.
OpenStax Chemistry
Chemistry definitions used for educational polarity, bonding, organic chemistry, and molecule-class explanations.