Carbon pentaoxide or carbon pentoxide is an unstable molecular oxide of carbon. The molecule has been produced and studied at cryogenic temperatures. The molecule is important in atmospheric chemistry and in the study of cold ices in the outer solar system and interstellar space. The substance could form and be present on Ganymede or Triton, moons in the outer solar system. The molecule has a C2 symmetry. It consists of a five membered ring with one carbon and four oxygen atoms. A fifth oxygen atom has a double bond to the carbon. Calculation has resulted in a theoretical structure. The pentagon is not regular, but varies in the length of its sides and angles. The distance between the oxygen atoms that are not attached to carbon is 1.406 Å, whereas the distance between one of these atoms and an oxygen attached to carbon is 1.457 Å. The carbon oxygen bond length is 1.376 Å. The double carbon to oxygen bond is the shortest at 1.180 Å. There is no carbon-to-carbon bond as there is only one carbon atom. The OOO bond angle is 100.2° and the OOC angle is 109.1°. The OCO bond angle is 125.4°.
3D model (JSmol)
|Molar mass||92.01 g/mol|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Carbon pentaoxide was produced by irradiating cryogenically frozen carbon dioxide with 5 keV electrons. The reaction mechanism is by carbon tetroxide reacting with an oxygen atom. This reaction releases 17.0 kJmol−1. Formation from ozone and carbon dioxide is energetically unfavourable by 165.6 kJmol−1, and carbon trioxide reacting with dioxygen molecules also would require 31.6 kJmol−1.
Vibrational infrared wavenumbers include the most prominent ν1 1912 cm−1 for the most common isotopologue 12C16O5. Potential routes for decomposition are by forming carbon dioxide and ozone, or carbon monoxide and oxygen, or carbon trioxide and oxygen. Carbon pentaoxide is less volatile than carbon dioxide, remaining stable and solid till about 106K.
An alternative theoretical structure, termed C2v, has a spiro structure with one four-member ring and a three-member ring tied perpendicularly at the carbon atom. However, this is 166 kJmol−1 higher in energy than the C2 isomer, and thus less likely to be formed. This isomer has not been detected.
The equivalent carbon pentasulfide is also known from inert gas matrix. It has C2 symmetry with the same atomic topology as the pentoxide.
Carbon hexoxide or carbon hexaoxide is an oxide of carbon with an unusually large quantity of oxygen. The molecule has been produced and studied at cryogenic temperatures. The molecule is important in atmospheric chemistry and in the study of cold ices in the outer solar system and interstellar space. The substance could form and be present on Ganymede or Triton, moons in the outer solar system. The molecule consists of a six membered ring with five oxygen and one carbon atom, and one oxygen with a double bond with the carbon.Oxocarbon
An oxocarbon or oxide of carbon is a chemical compound consisting only of carbon and oxygen.The simplest and most common oxocarbons are carbon monoxide (CO) and carbon dioxide (CO2) with IUPAC names carbon(II) oxide and carbon(IV) oxide respectively. Many other stable (practically if not thermodynamically) or metastable oxides of carbon are known, but they are rarely encountered, such as carbon suboxide (C3O2 or O=C=C=C=O) and mellitic anhydride (C12O9).
While textbooks will often list only the first three, and rarely the fourth, a large number of other oxides are known today, most of them synthesized since the 1960s. Some of these new oxides are stable at room temperature. Some are metastable or stable only at very low temperatures, but decompose to simpler oxocarbons when warmed. Many are inherently unstable and can be observed only momentarily as intermediates in chemical reactions or are so reactive that they can exist only in the gas phase or under matrix isolation conditions.
The inventory of oxocarbons appears to be steadily growing. The existence of graphene oxide and of other stable polymeric carbon oxides with unbounded molecular structures suggests that many more remain to be discovered.Pentoxide
Pentoxide may refer to:
Antimony pentoxide, Sb2O5
Arsenic pentoxide, As2O5
Carbon pentoxide, CO5
Dinitrogen pentoxide, N2O5
Iodine pentoxide, I2O5
Niobium pentoxide, Nb2O5
Phosphorus pentoxide, P4O10
Tantalum pentoxide, Ta2O5
Tungsten pentoxide, W18O49
|Compounds derived from oxides|