Sodium ruthenium(III,IV) oxide Na1-x Ru2O4 was synthesized by the solid state reaction of Na2CO3 and RuO2 in inert atmosphere and characterized by X-ray powder diffraction, electron diffraction, and high-resolution transmission electron microscopy. The compound crystallizes in the CaFe2O4-type structure (space group Pnma, Z = 4, a = 9.2641(7) Å, b = 2.8249(3) Å, c = 11.1496(7) Å). Double rutile-like chains of the RuO 6 octahedra form a three-dimensional framework, whose tunnels contain sodium cations. The structure contains two crystallographically independent sites of ruthenium atoms randomly occupied by the RuIII and Ru IV cations. The superstructure with the doubled b parameter found for one of the samples under study using electron diffraction is caused, probably, by ordering of the Ru cations in the rutile-like chains. The Na1- x Ru2O4 compound exhibits temperature-independent paramagnetism with χ0 = 1.9·10-4 cm3 (mole of Ru-1).
- CaFe O-type structure
- Double rutile-like chains
- Sodium nonstoichiometry
- Sodium ruthenium(III,IV) oxide
- Superstructure with doubling of b parameter