Strong Magneto-elastic coupling in VOCl: Neutron and synchrotron powder x-ray diffraction study

We present a combined neutron and synchrotron powder diffraction study of the crystal and magnetic structure of VOCl. The occurrence of antiferromagnetic order in VOCl is accompanied by a monoclinic distortion. The high sensitivity of the magnetic interaction parameters on V-O-V bond angles and V-V distances yields strong magnetoelastic coupling which implies the structural distortion below T$_N$ as well as anomalous structural effects in the paramagnetic phase.