Seven-Coordinated High-Pressure Phase of CrSb and Experimental Equation of State of Sb ( = Cr, Fe, Ru, Os).

The Sb compounds with = Cr, Fe, Ru, and Os have been investigated under high pressures by synchrotron powder X-ray diffraction. All compounds, except CrSb, were found to retain the marcasite structure up to the highest pressures (more than 50 GPa). In contrast, we found that CrSb has a structural phase transition around 10 GPa to a metastable, MoP-type structure with Cr coordinated to seven Sb atoms.

Singlet Orbital Ordering in Bilayer Sr_{3}Cr_{2}O_{7}.

We perform an extensive study of Sr_{3}Cr_{2}O_{7}, the n=2 member of the Ruddlesden-Popper Sr_{n+1}Cr_{n}O_{3n+1} system. An antiferromagnetic ordering is clearly visible in the magnetization and the specific heat, which yields a huge transition entropy, Rln(6). By neutron diffraction as a function of temperature we have determined the antiferromagnetic structure that coincides with the one obtained from density functional theory calculations.

BaCrO: A High Pressure Chromate with an Original Structure Solved by Electron Diffraction Tomography and Powder X-ray Diffraction.

We report on the discovery of a Ba-based chromate obtained by high pressure-high temperature treatment of the low pressure orthorhombic BaCrO phase. By combining transmission electron microscopy and powder X-ray diffraction measurements, we have determined its crystallographic structure. This new Cr-oxide has a cubic lattice with a = 13.