Long-range antiferromagnetic order in the S=1 chain compound LiVGe{sub 2}O{sub 6}

The phase transition in the compound LiVGe{sub 2}O{sub 6} has been proposed as a unique example of a spin-Peierls transition in an S=1 antiferromagnetic chain. We report neutron- and x-ray-diffraction measurements of LiVGe{sub 2}O{sub 6} above and below the phase transition at T=24 K. No evidence is seen for any structural distortion associated with the transition. The neutron results indicate that the low-temperature state is antiferromagnetic, driven by ferromagnetic interchain couplings.