Observation of small gas-phase metal–oxygen dianions

Novel small metal–oxygen dianions have been produced in the gas phase by sputtering of metallic targets with simultaneous oxygen flooding. These exotic species were observed in a mass spectrometer for ion flight times of >10 μs. Both Cs+ bombardment of an elemental Be metal surface and of a copper-based Cu(Be) alloy foil, with exposure of these sputtered surfaces to O2 gas, produced the novel dianions of Be n - 1 O n 2 - with n = 4, 6. Be 3 O 4 2 - at m/z 45.5 and 46.5 was unambiguously identified by its isotopic abundance. In addition, CuBe 2 O 4 2 - at m/z 72.5 and 73.5 was detected for O2 flooding of Cs+ sputtered Cu(Be).