Synthetic mineral libethenite Cu2PO4OH was prepared by the hydrothermal method, and its structure at 200 K was refined by single-crystal X-ray diffraction. The structure of Cu2PO 4OH is built up from Cu22O6(OH)2 dimers of edge-sharing Cu2O4(OH) trigonal bipyramids and [Cu1 2O6(OH)2]∝ chains of edge-sharing Cu1O4(OH)2 octahedra. Magnetic properties of Cu2PO4OH were investigated by magnetic susceptibility, magnetization, and specific heat measurements. Cu2PO4OH is a spin-gap system with a spin gap of about 139 K. It was shown by spin dimer analysis that, to a first approximation, the magnetic structure of Cu 2PO4OH is described by an isolated square-spin cluster model defined by the Cu1-O-Cu2 superexchange J with Cu1⋯Cu2 = 3.429 Å. The fitting analysis of the magnetic susceptibility data with a square-spin cluster model results in J/kB = 138 K. Specific heat data show that Cu2PO4OH does not undergo a long-range magnetic ordering down to 1.8 K. We also report vibrational properties studied with Raman spectroscopy and the thermal stability of Cu2PO4OH.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry