Oxygen cluster ion

In addition, such generic terms as metal-oxygen cluster ion, metal-oxide molecule, etc., are used for polyanions (and polyacids). Since the traditional heteropoly- and isopoly- are unsatisfactory terms to express a variety of polyacids and polyanions, the terms polyoxometalates and polyoxoacids have been used recently (3). The terminology is still changing, thus reflecting the rapid expansion of the chemistry. 

Aubriet, F, Maunit, B., Courtier, B., Muller, J.F. (1997) Studies of the chromium oxygenated cluster ions produced during the laser ablation of chromium oxides by laser ablation/ionization Fourier transform ion cyclotron resonance mass spectrometry. Rapid Communications in Mass Spectrometry, 11,1596-1601. 

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