Төрт атомды оттегінің аллотроптары

4 atom allotrope of oxygen
The tetraoxygen molecule (O4), also called oxozone, is an allotrope of oxygen consisting of four oxygen atoms.

Tetraoxygen was first predicted in 1924 by Gilbert N. Lewis, who proposed it as an explanation for the failure of liquid oxygen to obey Curie's law. Though not entirely inaccurate, computer simulations indicate that although there are no stable O4 molecules in liquid oxygen, O2 molecules do tend to associate in pairs with antiparallel spins, forming transient O4 units. In 1999, researchers thought that solid oxygen in its ε phase, also known as red oxygen, (at pressures above 10 GPa) was O4. However, in 2006, it was shown by X ray crystallography that this stable phase is in fact octaoxygen Nevertheless, positively charged tetraoxygen has been detected as a short lived chemical species in mass spectrometry experiments.

Theoretical calculations have predicted the existence of metastable O4 molecules with two different shapes: a "puckered" square like cyclobutane or S4, and a "pinwheel" with three oxygen atoms surrounding a central one in a trigonal planar formation similar to boron trifluoride or sulfur trioxide. It was previously pointed out that the "pinwheel" O4 molecule should be the natural continuation of the isoelectronic series BO33 , CO32 , NO3 , and analogous to SO3; that observation served as the basis for the mentioned theoretical calculations. Theoretical structures of metastable O4. D2d structureD3h structure

In 2001, a team at the University of Rome La Sapienza conducted a neutralization reionization mass spectrometry experiment to investigate the structure of free O4 molecules.