Dication
Encyclopedia
A dication is any cation, of general formula 2+, formed by the removal of two electrons from a neutral species.
Diatomic dications corresponding to stable neutral species (e.g. H22+ formed by removal of two electrons from H2) often decay quickly into two singly charged particles (H+), due to the loss of electrons in bonding molecular orbitals. Energy levels of diatomic dications can be studied with good resolution by measuring the yield of pairs of zero-kinetic-energy electrons from double photoionization of a molecule as a function of the photoionizing wavelength (threshold photoelectrons coincidence spectroscopy
- TPEsCO). The He22+ dication is kinetically stable.
An example of a stable diatomic dication which is not formed by oxidation of a neutral diatomic molecule is the dimercury dication Hg22+. An example of a polyatomic dication is S82+, formed by oxidation of S8 and unstable with respect to further oxidisation over time to form SO2.
Many organic dications can be detected in mass spectrometry
for example CH42+ (a CH22+ , H2 complex) and the acetylene dication C2H22+. The adamantyl dication
has been synthesized.
Diatomic dications corresponding to stable neutral species (e.g. H22+ formed by removal of two electrons from H2) often decay quickly into two singly charged particles (H+), due to the loss of electrons in bonding molecular orbitals. Energy levels of diatomic dications can be studied with good resolution by measuring the yield of pairs of zero-kinetic-energy electrons from double photoionization of a molecule as a function of the photoionizing wavelength (threshold photoelectrons coincidence 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...
- TPEsCO). The He22+ dication is kinetically stable.
An example of a stable diatomic dication which is not formed by oxidation of a neutral diatomic molecule is the dimercury dication Hg22+. An example of a polyatomic dication is S82+, formed by oxidation of S8 and unstable with respect to further oxidisation over time to form SO2.
Many organic dications can be detected in mass spectrometry
Mass spectrometry
Mass spectrometry is an analytical technique that measures the mass-to-charge ratio of charged particles.It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical structures of molecules, such as peptides and...
for example CH42+ (a CH22+ , H2 complex) and the acetylene dication C2H22+. The adamantyl dication
Adamantane
Adamantane is a colorless, crystalline chemical compound with a camphor-like odor. With a formula C10H16, it is a cycloalkane and also the simplest diamondoid. Adamantane molecules consist of three cyclohexane rings arranged in the "armchair" configuration. It is unique in that it is both rigid...
has been synthesized.