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 mu s. 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 02 gas, produced the novel dianions of Ben-1 O-n(2-) with n = 4, 6. Be3O42- at m/z 45.5 and 46.5 was unambiguously identified by its isotopic abundance. In addition, n 4 CuBe2 O-4(2-) at m/z 72.5 and 73.5 was detected for O-2 flooding of Cs+ sputtered Cu(Be).(c) 2005 Elsevier B.V. All rights reserved.