List of molecules in interstellar space

This is a list of molecules that have been detected in the interstellar medium

Interstellar medium

In astronomy, the interstellar medium is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space...

and circumstellar envelope

Circumstellar envelope

Circumstellar envelope is the part of the star,having roughly spherical shape and not gravitationally bound to the star core.Usually circumstellar envelopes are formed from the dense stellar wind or presentbefore formation of the star...

s, grouped by the number of component atom

Atom

The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...

s. The chemical formula

Chemical formula

A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

is listed for each detected compound, along with any ionized form that has also been observed.

Detection

The molecules listed below were detected by spectroscopy

Spectroscopy

Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...

. Their spectral features are generated by transitions of component electron

Electron

The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...

s between different energy levels, or by rotational or vibrational spectra. Detection usually occurs in radio

Radio

Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...

, microwave

Microwave

Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...

, or infrared

Infrared

Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

portions of the spectrum. The first such molecule to be detected in the interstellar medium was the methylidyne

Methylidyne

Methylidyne is a carbyne encountered in organic chemistry. Methylidyne has a linear doublet ground state and is thus paramagnetic. It is stable in the gaseous state. Methylidyne can be considered to be a monoradical; addition reactions are very fast and exothermic. Methylidyne tends to polymerise...

radical (CH) in 1937.

Interstellar molecules are formed by chemical reactions within very sparse interstellar or circumstellar clouds of dust and gas. Usually this occurs when a molecule becomes ionized, often as the result of an interaction with a cosmic ray

Cosmic ray

Cosmic rays are energetic charged subatomic particles, originating from outer space. They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation...

. This positively-charged molecule then draws in a nearby reactant by electrostatic attraction of the neutral molecule's electrons. Molecules can also be generated by reactions between neutral atoms and molecules, although this process is generally slower. The dust plays a critical role of shielding the molecules from the ionizing effect of ultraviolet radiation emitted by stars.

A particularly large and rich region for detecting interstellar molecules is Sagittarius B2

Sagittarius B2

Sagittarius B2 is a giant molecular cloud of gas and dust that is located about from the center of the Milky Way. This complex is the largest molecular cloud in the vicinity of the core and one of the largest in the galaxy, spanning a region about across. The total mass of Sgr B2 is about 3...

(Sgr B2). This giant molecular cloud

Molecular cloud

A molecular cloud, sometimes called a stellar nursery if star formation is occurring within, is a type of interstellar cloud whose density and size permits the formation of molecules, most commonly molecular hydrogen ....

lies near the center of the Milky Way

Milky Way

The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...

galaxy and is a frequent target for new searches. About half of the molecules listed below were first found near Sgr B2, and nearly every other molecule has since been detected in this feature. A rich source of investigation for circumstellar molecules is the relatively nearby star CW Leonis (IRC +10216), where about 50 molecules have been identified.

Molecules

The following tables list molecules that have been detected in the interstellar medium, grouped by the number of component atom

Atom

s. If there is no entry in the Molecule column, only the ionized form has been detected. For molecules where no designation was given in the scientific literature, that field is left empty. Mass is given in Atomic mass unit

Atomic mass unit

The unified atomic mass unit or dalton is a unit that is used for indicating mass on an atomic or molecular scale. It is defined as one twelfth of the rest mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state, and has a value of...

s. The total number of unique species is listed in parentheses in each section header.

Diatomic (32)

Molecule	\|Mass	AlCl	Aluminium monochloride Aluminium monochloride Aluminium monochloride is the metal halide with the formula AlCl. This compound is produced as a step in the Alcan process to smelt aluminium from an aluminium-rich alloy...	62.5	—
AlF	Aluminium monofluoride Aluminium monofluoride Aluminium monofluoride is the chemical substance with the formula AlF. This elusive species is formed by the reaction between aluminium trifluoride and metallic aluminium at elevated temperatures but quickly reverts back to the reactants when cooled...	46	—
AlO	Aluminium monoxide	43	—
C₂	Diatomic carbon Diatomic carbon Diatomic carbon is a diatomic molecule of carbon , which occurs in electric arcs; in comets, stellar atmospheres and the interstellar medium; and in blue hydrocarbon flames.-Chemistry:...	24	—
—	Fluoromethylidynium	31	CF⁺
CH	Methylidyne Methylidyne Methylidyne is a carbyne encountered in organic chemistry. Methylidyne has a linear doublet ground state and is thus paramagnetic. It is stable in the gaseous state. Methylidyne can be considered to be a monoradical; addition reactions are very fast and exothermic. Methylidyne tends to polymerise... radical Radical (chemistry) Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...	13	CH⁺

|-
|align="center"|CN||Cyanogen

Cyanogen

Cyanogen is the chemical compound with the formula 2. It is a colorless, toxic gas with a pungent odor.The molecule is a pseudohalogen. Cyanogen molecules consist of two CN groups — analogous to diatomic halogen molecules, such as Cl2, but far less oxidizing...

radical

Radical (chemistry)

Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...

|align="center"|26||align="center"|CN⁺, CN^-
|-
|align="center"|CO||Carbon monoxide

Carbon monoxide

Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...

|align="center"|28||align="center"|CO⁺
|-
|align="center"|CP||Carbon monophosphide
|align="center"|43||align="center"|—
|-
|align="center"|CS||Carbon monosulfide

Carbon monosulfide

Carbon monosulfide is a chemical compound with the formula CS. This diatomic molecule is the sulfur analogue of carbon monoxide, and is unstable as a solid or a liquid, but it has been observed as a gas both in the laboratory and in the interstellar medium. The molecule resembles carbon monoxide...

|align="center"|44||align="center"|—
|-
|align="center"|FeO||Iron(II) oxide

Iron(II) oxide

Iron oxide, also known as ferrous oxide, is one of the iron oxides. It is a black-colored powder with the chemical formula . It consists of the chemical element iron in the oxidation state of 2 bonded to oxygen. Its mineral form is known as wüstite. Iron oxide should not be confused with rust,...

|align="center"|82||align="center"|—
|-
|align="center"|H₂||Molecular hydrogen

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

|align="center"|2||align="center"|—
|-
|align="center"|HCl||Hydrogen chloride

Hydrogen chloride

The compound hydrogen chloride has the formula HCl. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric humidity. Hydrogen chloride gas and hydrochloric acid are important in technology and industry...

|align="center"|36.5||align="center"|—
|-
|align="center"|HF||Hydrogen fluoride

Hydrogen fluoride

Hydrogen fluoride is a chemical compound with the formula HF. This colorless gas is the principal industrial source of fluorine, often in the aqueous form as hydrofluoric acid, and thus is the precursor to many important compounds including pharmaceuticals and polymers . HF is widely used in the...

|align="center"|20||align="center"|—
|-
|align="center"|HO||Hydroxyl radical

Hydroxyl radical

The hydroxyl radical, •OH, is the neutral form of the hydroxide ion . Hydroxyl radicals are highly reactive and consequently short-lived; however, they form an important part of radical chemistry. Most notably hydroxyl radicals are produced from the decomposition of hydroperoxides or, in...

|align="center"|17||align="center"|OH⁺
|-
|align="center"|KCl||Potassium chloride

Potassium chloride

The chemical compound potassium chloride is a metal halide salt composed of potassium and chlorine. In its pure state, it is odorless and has a white or colorless vitreous crystal appearance, with a crystal structure that cleaves easily in three directions. Potassium chloride crystals are...

|align="center"|75.5||align="center"|—
|-
|align="center"|NH||Nitrogen monohydride
|align="center"|15||align="center"|—
|-
|align="center"|N₂||Molecular nitrogen

Nitrogen

Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

|align="center"|28||align="center"|—
|-
|align="center"|NO||Nitric oxide

Nitric oxide

Nitric oxide, also known as nitrogen monoxide, is a diatomic molecule with chemical formula NO. It is a free radical and is an important intermediate in the chemical industry...

|align="center"|30||align="center"|NO⁺
|-
|align="center"|NS||Nitrogen sulfide

Mononitrogen monosulfide

Mononitrogen monosulfide is an inorganic compound with the formula SN. It is the sulfur analogue of nitric oxide, NO. It can be produced through electrical discharges in mixtures of nitrogen and sulfur compounds, as well as the reaction of nitrogen with sulfur vapor. The valence electrons of this...

|align="center"|46||align="center"|—
|-
|align="center"|NaCl||Sodium chloride

Sodium chloride

Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...

|align="center"|58.5||align="center"|—
|-
|align="center"|—||Magnesium monohydride cation
|align="center"|25.3||align="center"|MgH⁺
|-
|align="center"|NaI||Sodium iodide

Sodium iodide

Sodium iodide is a white, crystalline salt with chemical formula NaI used in radiation detection, treatment of iodine deficiency, and as a reactant in the Finkelstein reaction.-Uses:Sodium iodide is commonly used to treat and prevent iodine deficiency....

|align="center"|150||align="center"|—
|-
|align="center"|O₂||Molecular oxygen
|align="center"|32||align="center"|—
|-
|align="center"|PN||Phosphorus nitride
|align="center"|45||align="center"|—
|-
|align="center"|PO||Phosphorus monoxide
|align="center"|47||align="center"|—
|-
|align="center"|SH||Sulfur monohydride
|align="center"|33||align="center"|SH⁺
|-
|align="center"|SO||Sulfur monoxide

Sulfur monoxide

Sulfur monoxide is an inorganic compound with formula . It is only found as a dilute gas phase. When concentrated or condensed, it converts to S2O2 . It has been detected in space but is rarely encountered intact otherwise.-Structure and bonding:The SO molecule has a triplet ground state similar...

|align="center"|48||align="center"|SO⁺
|-
|align="center"|SiC||Carborundum

Silicon carbide

Silicon carbide , also known as carborundum, is a compound of silicon and carbon with chemical formula SiC. It occurs in nature as the extremely rare mineral moissanite. Silicon carbide powder has been mass-produced since 1893 for use as an abrasive...

|align="center"|40||align="center"|—
|-
|align="center"|SiN||Silicon mononitride
|align="center"|42||align="center"|—
|-
|align="center"|SiO||Silicon monoxide

Silicon monoxide

Silicon monoxide is the chemical compound with the formula SiO. In the vapour phase it is a diatomic molecule. It has been detected in stellar objects and it has been described as the most common oxide of silicon in the universe....

|align="center"|44||align="center"|—
|-
|align="center"|SiS||Silicon monosulfide
|align="center"|60||align="center"|—
|}

Triatomic (37)

Molecule	\|Mass	AlNC	Aluminium isocyanide	53	—
AlOH	Aluminium hydroxide Aluminium hydroxide Aluminium hydroxide, Al3, ATH, sometimes erroneously called Hydrate of alumina, is found in nature as the mineral gibbsite and its three, much more rare forms, polymorphs: bayerite, doyleite and nordstrandite. Closely related are aluminium oxide hydroxide, AlO, and aluminium oxide, Al2O3,...	44	—
C₃	Tricarbon Tricarbon Tricarbon or C3 is a small carbon cluster first spectroscopically observed in the beginning 20th century in the tail of a comet by William Huggins and subsequently identified in stellar atmospheres. Tricarbon can be found in interstellar space and can be produced in the laboratory by a process...	36	—
C₂H	Ethynyl radical Ethynyl radical The ethynyl radical, with chemical formula C2H, is an abundant interstellar polyatomic molecule that does not occur naturally on Earth. It was first observed by electron spin resonance isolated in a solid argon matrix at liquid helium temperatures in 1963 by Cochran and coworkers at the Johns...	25	—
C₂O	Dicarbon monoxide Dicarbon monoxide Dicarbon monoxide is an extremely reactive molecule that contains two carbon atoms and one oxygen atom. Dicarbon monoxide, covalently bonded, is a product of the photolysis of carbon suboxide. It is closely related to CO, CO2 and C3O2, and other oxocarbons.It is stable enough to observe reactions...	40	—
C₂S	Thioxoethenylidene	56	—
C₂P	—	55	—
CO₂	Carbon dioxide Carbon dioxide Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...	44	—
FeCN	Iron cyanide	82	—
—	Protonated molecular hydrogen Protonated molecular hydrogen Protonated molecular hydrogen, trihydrogen cation, or H3+, is one of the most abundant ions in the universe. It is stable in the interstellar medium due to the low temperature and low density of interstellar space. The role that H3+ plays in the gas-phase chemistry of the ISM is unparalleled by...	3	H₃⁺
H₂C	Methylene Methylene Methylene is a chemical species in which a carbon atom is bonded to two hydrogen atoms. Three different possibilities present themselves:* the -CH2- substituent group: e.g., dichloromethane ....	14	—
—	Chloronium Halonium ion A halonium ion in organic chemistry is any onium compound containing a halogen atom carrying a positive charge. This cation has the general structure R-X+-R where X is any halogen and R any organic residue and this structure can be cyclic or an open chain molecular structure...	37.5	H₂Cl⁺
H₂O	Water Water Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...	18	H₂O⁺
H₂S	Hydrogen sulfide Hydrogen sulfide Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...	34	—
HCN	Hydrogen cyanide	27	—
HNC	Hydrogen isocyanide Hydrogen isocyanide Hydrogen isocyanide is a chemical with the molecular formula HNC. It is a minor tautomer of hydrogen cyanide, HCN). Its importance in the field of astrochemistry is linked to its ubiquity in the interstellar medium.- Nomenclature :...	27	—
HCO	Formyl radical	29	HCO⁺
HCP	Phosphaethyne	44	—
—	Thioformyl	45	HCS⁺
HNC	Hydrogen isocyanide Hydrogen isocyanide Hydrogen isocyanide is a chemical with the molecular formula HNC. It is a minor tautomer of hydrogen cyanide, HCN). Its importance in the field of astrochemistry is linked to its ubiquity in the interstellar medium.- Nomenclature :...	27	—
—	Diazenylium Diazenylium N2H+, known as diazenylium, was one of the first ions to be observed in interstellar clouds. Since then, it has been observed for a variety of purposes in several different types of interstellar environments...	29	HN₂⁺
HNO	Nitroxyl Nitroxyl Nitroxyl is the chemical compound HNO. It is well known in the gas phase . In aqueous solution it acts as an acid with the conjugate base NO−, . NO− is the reduced form of nitric oxide and is isoelectronic with dioxygen...	31	—
—	Isoformyl	29	HOC⁺
KCN	Potassium cyanide Potassium cyanide Potassium cyanide is an inorganic compound with the formula KCN. This colorless crystalline compound, similar in appearance to sugar, is highly soluble in water. Most KCN is used in gold mining, organic synthesis, and electroplating. Smaller applications include jewelry for chemical gilding and...	65	—
MgCN	Magnesium cyanide	50	—
MgNC	Magnesium isocyanide	50	—
NH₂	Amino radical	16	—
—	—	29	N_2H⁺
N₂O	Nitrous oxide Nitrous oxide Nitrous oxide, commonly known as laughing gas or sweet air, is a chemical compound with the formula . It is an oxide of nitrogen. At room temperature, it is a colorless non-flammable gas, with a slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic...	44	—
NaCN	Sodium cyanide Sodium cyanide Sodium cyanide is an inorganic compound with the formula NaCN. This highly toxic colorless salt is used mainly in gold mining but has other niche applications...	49	—
NaOH	Sodium hydroxide	40	—
OCS	Carbonyl sulfide Carbonyl sulfide Carbonyl sulfide is the chemical compound with the formula OCS. Commonly written as COS, it is a colourless flammable gas with an unpleasant odor. It is a linear molecule consisting of a carbonyl group double bonded to a sulfur atom...	60	—
O₃	Ozone Ozone Ozone , or trioxygen, is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope...	48	—
SO₂	Sulfur dioxide Sulfur dioxide Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...	64	—
c-SiC₂	c-Silicon dicarbide name="aass226" />	52	—
SiCN	Silicon carbonitride	54	—
SiNC	Silicon naphthalocyanine	54	—

Four atoms (22)

Molecule	\|Mass	CH₃	Methyl	15	—
l-C₃H	Propynylidyne Propynylidyne Propynylidyne is a chemical compound that has been identified in interstellar space.- Simulated spectrum :A rotational spectrum of the 2Π electronic ground state of l-C3H can be made using the PGopher software and molecular constants extracted from the literature...	37	—
c-C₃H	Cyclopropynylidyne	37	—
C₃N	Cyanoethynyl	50	C₃N⁻
C₃O	Tricarbon Carbon Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds... monoxide Oxygen Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...	52	—
C₃S	Tricarbon Carbon Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds... sulfide Sulfide A sulfide is an anion of sulfur in its lowest oxidation state of 2-. Sulfide is also a slightly archaic term for thioethers, a common type of organosulfur compound that are well known for their bad odors.- Properties :...	68	—
—	Hydronium Hydronium In chemistry, a hydronium ion is the cation , a type of oxonium ion produced by protonation of water. This cation is often used to represent the nature of the proton in aqueous solution, where the proton is highly solvated...	19	H₃O⁺
C₂H₂	Acetylene Acetylene Acetylene is the chemical compound with the formula C2H2. It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in pure form and thus is usually handled as a solution.As an alkyne, acetylene is unsaturated because...	26	—
H₂CN	Methylene Methylene Methylene is a chemical species in which a carbon atom is bonded to two hydrogen atoms. Three different possibilities present themselves:* the -CH2- substituent group: e.g., dichloromethane .... amidogen	28	H₂CN⁺
H₂CO	Formaldehyde Interstellar formaldehyde Interstellar formaldehyde was first discovered in 1969 by L. Snyder et al.. using the National Radio Astronomy Observatory. Formaldehyde was detected by means of the 111 - 110 ground state rotational transition at 4830 MHz.-Initial discovery:Formaldehyde was first discovered in interstellar...	30	—
H₂CS	Thioformaldehyde	46	—
HCCN	—	39	—
—	Protonated hydrogen cyanide	28	HCNH⁺ HCNH+ HCNH+, also known as protonated hydrogen cyanide, is a molecular ion of astrophysical interest.- Structure :The ground state structure of HCNH+ is a simple linear molecule...
—	Protonated carbon dioxide Carbon dioxide Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...	45	HOCO⁺
HCNO	Fulminic acid Fulminic acid Fulminic acid is a compound with a molecular formula HCNO. This substance was discovered in 1824 by Justus von Liebig. It is an organic acid and an isomer of isocyanic acid, discovered one year later by Friedrich Woehler....	43	—
HOCN	Cyanic acid	43	—
HOOH	Hydrogen peroxide Hydrogen peroxide Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...	34	—
HNCO	Isocyanic acid Isocyanic acid Isocyanic acid is an inorganic compound with the formula HNCO, discovered in 1830 by Liebig and Wöhler. This colourless substance is volatile and poisonous, with a boiling point of 23.5 °C...	43	—
HNCS	Isothiocyanic acid	59	—
NH₃	Ammonia Ammonia Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...	17	—
HSCN	Thiocyanic acid Thiocyanic acid Thiocyanic acid is a chemical compound with the formula HSCN that exists as a mixture with the isomeric compound isothiocyanic acid . It is the sulfur analog of cyanic acid ....	59	—
SiC₃	Silicon tricarbide	64	—

Five atoms (16)

Molecule	\|Mass	C₅	—	60	—
CH₄	Methane Methane Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...	16	—
c-C₃H₂	Cyclopropenylidene Cyclopropenylidene Cylopropenylidene, or c-C3H2 belongs to a highly reactive class of organic molecules known as carbenes. Due to its reactivity, cyclopropenylidene is only seen terrestrially in the laboratory. However, it is found in significant concentrations in the interstellar medium due to the extreme environment...	38	—
l-H₂C₃	Propadienylidene	38	—
H₂CCN	Cyanomethyl	40	—
H₂C₂O	Ketene Ethenone Ethenone is the formal name for ketene, an organic compound with formula C2H2O or H2C=C=O. It is the simplest member of the ketene class. It is a tautomer of ethynol.- Properties :...	42	—
H₂CNH	Methylenimine	29	—
—	Protonated formaldehyde	31	H₂COH⁺
C₄H	Butadiynyl	49	C₄H^–
HC₃N	Cyanoacetylene Cyanoacetylene Cyanoacetylene is an organic compound with formula or H-C≡C-C≡N. It is the simplest cyanopolyyne. Cyanoacetylene has been detected by spectroscopic methods in interstellar clouds, in the coma of comet Hale–Bopp and in the atmosphere of Saturn's moon Titan....	51	—
HCC-NC	Isocyanoacetylene	51	—
HCOOH	Formic acid Formic acid Formic acid is the simplest carboxylic acid. Its chemical formula is HCOOH or HCO2H. It is an important intermediate in chemical synthesis and occurs naturally, most notably in the venom of bee and ant stings. In fact, its name comes from the Latin word for ant, formica, referring to its early...	46	—
NH₂CN	Cyanamide Cyanamide Cyanamide is an organic compound with the formula CN2H2. This white solid is widely used in agriculture and the production of pharmaceuticals and other organic compounds. It is also used as an alcohol deterrent drug in Canada, Europe and Japan. The molecule features a nitrile group attached to an...	42	—
HC(O)CN	Cyanoformaldehyde	55	—
SiC₄	Silicon-carbide cluster	92	—
SiH₄	Silane Silane Silane is a toxic, extremely flammable chemical compound with chemical formula SiH4. In 1857, the German chemists and Friedrich Woehler discovered silane among the products formed by the action of hydrochloric acid on aluminum silicide, which they had previously prepared...	32	—

Six atoms (14)


Molecule	\|Mass	c-H₂C₃O	Cyclopropenone	54	—
C₂H₄	Ethylene Ethylene Ethylene is a gaseous organic compound with the formula . It is the simplest alkene . Because it contains a carbon-carbon double bond, ethylene is classified as an unsaturated hydrocarbon. Ethylene is widely used in industry and is also a plant hormone...	28	—
CH₃CN	Acetonitrile Acetonitrile Acetonitrile is the chemical compound with formula . This colourless liquid is the simplest organic nitrile. It is produced mainly as a byproduct of acrylonitrile manufacture...	40	—
CH₃NC	Methyl isocyanide Methyl isocyanide Methyl isocyanide or Isocyanomethane is an organic compound and a member of the isocyanide family. This colorless liquid is structurally similar to the isomeric methyl cyanide , but its reactivity is very different...	40	—
CH₃OH	Methanol Methanol Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...	32	—
CH₃SH	Methanethiol Methanethiol Methanethiol is a colorless gas with a smell like rotten cabbage. It is a natural substance found in the blood and brain of humans and other animal as well as plant tissues. It is disposed of through animal feces. It occurs naturally in certain foods, such as some nuts and cheese...	48	—
l-H₂C₄	Diacetylene Diacetylene Diacetylene , with the formula C4H2, is a highly unsaturated hydrocarbon that contains three single bonds and two triple bonds. It is the first in the series of polyynes.-Occurrence:...	50	—
—	Protonated cyanoacetylene	52	HC₃NH⁺
HCONH₂	Formamide Formamide Formamide, also known as methanamide, is an amide derived from formic acid. It is a clear liquid which is miscible with water and has an ammonia-like odor. It is used primarily for manufacturing sulfa drugs and synthesizing vitamins and as a softener for paper and fiber...	44	—
C₅H	Pentynylidyne	61	—
C₅N	Cyanobutadiynyl	74	—
HC₂CHO	Propynal	54	—
HC₄N	—	63	—
CH₂CNH	Ketenimine Ketenimine Ketenimines are a group of organic compounds sharing a common functional group with the general structure R1R2C=C=NR3. A ketenimine is a cumulated alkene and imine and is related to an allene and a ketene.The parent compound is ketenimine or CH2CNH...	40	—

Seven atoms (8)

Molecule	\|Mass	c-C₂H₄O	Ethylene oxide Ethylene oxide Ethylene oxide, also called oxirane, is the organic compound with the formula . It is a cyclic ether. This means that it is composed of two alkyl groups attached to an oxygen atom in a cyclic shape . This colorless flammable gas with a faintly sweet odor is the simplest epoxide, a three-membered...	44	—
CH₃C₂H	Methylacetylene Methylacetylene Methylacetylene is an alkyne with the chemical formula H3C≡CH. It is a component of MAPP gas along with its isomer 1,2-propadiene , which is commonly used in gas welding...	40	—
H₃CNH₂	Methylamine Methylamine Methylamine is the organic compound with a formula of CH3NH2. This colourless gas is a derivative of ammonia, but with one H atom replaced by a methyl group. It is the simplest primary amine. It is sold as a solution in methanol, ethanol, THF, and water, or as the anhydrous gas in pressurized...	31	—
CH₂CHCN	Acrylonitrile Acrylonitrile Acrylonitrile is the chemical compound with the formula C3H3N. This pungent-smelling colorless liquid often appears yellow due to impurities. It is an important monomer for the manufacture of useful plastics. In terms of its molecular structure, it consists of a vinyl group linked to a nitrile...	53	—
H₂CHCOH	Vinyl alcohol	44	—
C₆H	Hexatriynyl	73	C₆H^–
HC₄CN	Cyanodiacetylene	75	—
CH₃CHO	Acetaldehyde Acetaldehyde Acetaldehyde is an organic chemical compound with the formula CH3CHO or MeCHO. It is one of the most important aldehydes, occurring widely in nature and being produced on a large scale industrially. Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants as part...	44	—

Eight atoms (9)

Molecule	\|Mass
H₃CC₂CN	Methylcyanoacetylene	65
H₂COHCHO	Glycolaldehyde Glycolaldehyde Glycolaldehyde is the smallest possible molecule that contains both an aldehyde group and a hydroxyl group. It is the only possible diose, a 2-carbon monosaccharide, although a diose is not strictly a saccharide...	60
HCOOCH₃	Methyl formate Methyl formate Methyl formate, also called methyl methanoate, is the methyl ester of formic acid. The simplest example of an ester, it is a clear liquid with an ethereal odor, high vapor pressure, and low surface tension.-Production:...	60
CH₃COOH	Acetic acid Acetic acid Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...	60
H₂C₆	Hexapentaenylidene	74
CH₂CHCHO	Propenal Acrolein Acrolein is the simplest unsaturated aldehyde. It is produced widely but is most often immediately reacted with other products due to its instability and toxicity...	56
CH₂CCHCN	Cyanoallene	65
C₇H	Heptatrienyl radical	85
NH₂CH₂CN	Aminoacetonitrile Aminoacetonitrile Aminoacetonitrile is a simple organic compound containing both nitrile and amino groups. It is somewhat similar to the simplest amino acid, glycine...	56

Nine atoms (8)

Molecule	\|Mass	CH₃C₄H	Methyldiacetylene	64	—
CH₃OCH₃	Dimethyl Ether Dimethyl ether Dimethyl ether , also known as methoxymethane, is the organic compound with the formula . The simplest ether, it is a colourless gas that is a useful precursor to other organic compounds and an aerosol propellant. When combusted, DME produces minimal soot and CO, though HC and NOx formation is...	46	—
CH₃CH₂CN	Propionitrile Propionitrile Propanenitrile, Propionitrile or ethyl cyanide, is a nitrile with the molecular formula C2H5CN. It is a clear liquid with an ethereal, sweet odor.-Production:...	55	—
CH₃CONH₂	Acetamide Acetamide Acetamide is an organic compound with the formula CH3CONH2. It is the simplest amide derived from acetic acid. It finds some use as a plasticizer and as an industrial solvent...	59	—
CH₃CH₂OH	Ethyl Alcohol Ethanol Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...	46	—
C₈H	Octatetraynyl	97	C₈H^–
HC₇N	Cyanohexatriyne or Cyanotriacetylene	99	—
CH₃CHCH₂	Propylene (propene) Propylene Propene, also known as propylene or methylethylene, is an unsaturated organic compound having the chemical formula C3H6. It has one double bond, and is the second simplest member of the alkene class of hydrocarbons, and it is also second in natural abundance.-Properties:At room temperature and...	42	—

Ten or more atoms (15)

Atoms	\|Designation	\|Ions
10	(CH₃)₂CO	Acetone Acetone Acetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...	58	—
10	(CH₂OH)₂	Ethylene glycol Ethylene glycol Ethylene glycol is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid...	62	—
10	CH₃CH₂CHO	Propanal Propionaldehyde Propionaldehyde or propanal is the organic compound with the formula CH3CH2CHO. It is a saturated 3-carbon aldehyde and is a structural isomer of acetone...	58	—
10	CH₃C₅N	Methyl-cyano-diacetylene	89	—
11	HC₈CN	Cyanotetra-acetylene	123	—
11	C₂H₅OCHO	Ethyl formate Ethyl formate Ethyl formate is an ester formed when ethanol reacts with formic acid . It is also known as ethyl methanoate because formic acid is also known as methanoic acid. Ethyl formate has the characteristic smell of rum and is also partially responsible for the flavor of raspberries.-Exposure:Ethyl...	74	—
11	CH₃C₆H	Methyltriacetylene	88	—
11	H₃COC₂H₅	trans-Ethyl methyl ether	60	—
12	C₆H₆	Benzene Benzene Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....	78	—
12	C₃H₇CN	n-propyl cyanide Butyronitrile Butyronitrile or butanenitrile or propyl cyanide, is a nitrile with the formula C3H7CN. This colorless liquid is miscible with most polar organic solvents. It is mainly used as a precursor to the poultry drug amprolium....	69	—
13	HC₁₀CN	Cyanodecapentayne	147	—
13	HC₁₁N	—	159	—
24	C₁₄H₁₀	Anthracene Anthracene Anthracene is a solid polycyclic aromatic hydrocarbon consisting of three fused benzene rings. It is a component of coal-tar. Anthracene is used in the production of the red dye alizarin and other dyes...	178	—
60	C₆₀	Buckminsterfullerene Buckminsterfullerene Buckminsterfullerene is a spherical fullerene molecule with the formula . It was first intentionally prepared in 1985 by Harold Kroto, James Heath, Sean O'Brien, Robert Curl and Richard Smalley at Rice University...	720	—
70	C₇₀	70-fullerene Fullerene A fullerene is any molecule composed entirely of carbon, in the form of a hollow sphere, ellipsoid, or tube. Spherical fullerenes are also called buckyballs, and they resemble the balls used in association football. Cylindrical ones are called carbon nanotubes or buckytubes...	840	—

Deuterated molecules (10)

These molecules all contain one or more deuterium

Deuterium

Deuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...

atoms, a heavier isotope

Isotope

Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...

of hydrogen