Unconventional magnetism as a consequence of the charge   disproportionation and the molecular orbital formation in Ba4Ru3O10
  The magnetic and electronic properties of Ba$_4$Ru$_3$O$_{10}$ were investigated by the ab-initio and model calculations. It is shown that nonmagnetic ground state of the one-third Ru$^{4+}$ ions is not due to the correlation effects. It is rather caused by the charge disproportionation between crystallographically different Ru and the molecular orbital formation in the Ru's trimer. 
S.V. Streltsov and D.I. Khomskii
cond-mat.str-el