Tricarbon monosulfide (C3S) or tricarbon sulfur is a reactive molecular substance that has been detected in
outer space
Outer space, commonly shortened to space, is the expanse that exists beyond Earth and its atmosphere and between celestial bodies. Outer space is not completely empty—it is a near-perfect vacuum containing a low density of particles, pred ...
. Tricarbon monosulfide is a
heterocumulene A heterocumulene is a molecule or ion containing a chain of at least three double bonds between consecutive atoms, in which one or more atoms in the doubly bonded chain is a heteroatom. Such species are analogous to a cumulene in which the chain of ...
or thiocumulene, consisting of a straight chain of three
carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent
In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...
atoms and a terminal
sulfur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...
debye
The debye (symbol: D) (; ) is a CGS unit (a non- SI metric unit) of electric dipole momentTwo equal and opposite charges separated by some distance constitute an electric dipole. This dipole possesses an electric dipole moment whose value is give ...
. The bond lengths are 1.275 Å, for terminal C=C bond, 1.292 Å for internal bond, and 1.535 Å for the C=S bond. The similar bond lengths between the carbon atoms indicate they each have a
double bond
In chemistry, a double bond is a covalent bond between two atoms involving four bonding electrons as opposed to two in a single bond. Double bonds occur most commonly between two carbon atoms, for example in alkenes. Many double bonds exist betw ...
nature. The rotational constants for 12C12C12C32S are B0 = 2890.38000 MHz and D0 = 0.00022416.
There is a characteristic infrared absorption band at 2047.5 cm−1 due to stretching of a C=C bond.
Formation
Along with the related dicarbon monosulfide (CCS), tricarbon monosulfide was made by a glow discharge though
carbon disulfide
Carbon disulfide (also spelled as carbon disulphide) is a neurotoxic, colorless, volatile liquid with the formula and structure . The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non ...
vapour in helium. Microwave emission lines from rotational transitions matched up with previously unknown molecular lines from the Taurus molecular cloud 1. Maximal concentrations occurred with a carbon disulfide pressure of 0.02
torr
The torr (symbol: Torr) is a unit of pressure based on an absolute scale, defined as exactly of a standard atmosphere (). Thus one torr is exactly (≈ ).
Historically, one torr was intended to be the same as one "millimeter of mercury ...
.
In molecular clouds, the formation mechanism is speculated to be CCS + CH → CCCS + H.
On dust grains, in space the formation mechanism is theorised to be:
CCC
CCC may refer to:
Arts and entertainment
* Canada's Capital Cappies, the Critics and Awards Program in Ottawa, Ontario, Canada
* ''Capcom Classics Collection'', a 2005 compilation of arcade games for the PlayStation 2 and Xbox
* CCC, the pro ...
+ H2S → C3•HSH → CCCS + H2 when irradiated with visible or UV light. THis reaction has been reproduced in a solid argon matrix.
Natural occurrence
Tricarbon monosulfide has been detected in
molecular cloud
A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit absorption nebulae, the formation of molecules (most commonly molecular hydrogen ...
Kleinmann–Low Nebula
The Kleinmann–Low Nebula (also known as the Orion KL Nebula) is an active star forming region in the Milky Way galaxy. It is a cluster of stars within a molecular cloud.Ferland pp191
The Kleinmann–Low Nebula is at the heart of the Orion Ne ...
. The ratio of
tricarbon monoxide
Tricarbon monoxide C3O is a reactive radical oxocarbon molecule found in space, and which can be made as a transient substance in the laboratory. It can be trapped in an inert gas matrix or made as a short lived gas. C3O can be classified as a k ...
to tricarbon monosulfide reflects the ratio of sulfur to oxygen in the cloud. The ratio of concentration of sulfur to oxygen analogues follows the same pattern. The clouds can be cold and dark, or warm. CCCS has also been found in the stellar envelope of carbon-rich AGB stars, including in IRC+10216.