The dioxygenyl ion
, is a rarely-encountered oxycation
in which both oxygen atoms
have an oxidation state
of +½. It is formally derived from oxygen
by the removal of an electron
- O2 → O2+ + e−
The energy change for this process is called the ionization energy
of the oxygen molecule. Relative to most molecules, this ionization energy is very high at 1165 kJ/mol.
Structure and molecular properties
has a bond order
of 2.5, and a bond length
of 112.3 pm. It has the same number of valence electrons as nitric oxide
. The bond energy
is 625.1 kJ mol−1
and stretching frequency of 1858 cm−1
, both of which are high relative to most molecules.
The reaction of dioxygen, O2
, with platinum hexafluoride
, yields dioxygenyl hexafluoroplatinate, O2
- O2 + PtF6 → O2[PtF6]
is one of the few oxidising agents sufficiently powerful to oxidise O2
Dioxygenyl hexafluoroplatinate played a pivotal role in the discovery of noble gas compounds. After Neil Bartlett found that PtF6 could oxidise O2 to O2+, he investigated its reaction with noble gases and discovered "xenon hexafluoroplatinate. "
is also found in the similar compound O2
], dioxygenyl hexafluoroarsenate.