Abstract of Publication No. 556
Nuclear and magnetic structures of sodium ruthenate (VI) have been studied by
neutron powder diffraction in the temperature range 1.5–200 K.
Na2RuO4 crystallizes in the monoclinic structure, with
space group P 21/c. The structure consists of apical corner sharing
RuO5 trigonal bipyramids forming infinite chains running along the b
axis. These infinite [ RuO3O2/2] chains form a pseudo
hexagonal close packing of rods with Ru–Ru distances of 3.51 Å within the chains
and 5.30–5.47 Å between the chains. At TN = 37.2 K a magnetic
transition leads to an antiferromagnetic state. The Ru6+ magnetic
moments are ordered antiferromagnetically along the chains (b-axis), while the
inter-chain interaction is ferromagnetic. A classical infinite chain model was
fitted to the magnetic susceptibility data in order to estimate the strength of
the nearest-neighbor exchange interactions along and between the chains,
resulting in an intrachain coupling parameter of 2J = -86 K, and an interchain
with |2J| = 3 K.