Structure, characterization, and properties of BaMoO4 and BaKYb(MoO4)3 flux-grown single-crystals

Crystals of the barium molybdates BaKYb(MoO4)3 and BaMoO4 were obtained by spontaneous nucleation from high-temperature flux experiments. The compounds were characterized by energy-dispersive spectrometry (EDS) and Raman spectroscopy, and their structure was solved from single-crystal X-ray diffraction data at room temperature. BaMoO4 crystallizes in the tetragonal I41/a symmetry with a ​= ​b ​= ​5.5723(4) and c ​= ​12.7954(9) Å. With the scheelite-type structure, BaMoO4 displays sharp and intense lines in its FT-Raman spectrum registered at room temperature. The new triple molybdate BaKYb(MoO4)3 is described in a monoclinic lattice C2/c of parameters a ​= ​17.3517(5), b ​= ​12.1477(4), c ​= ​5.2481(2) Å, β = 105.344(2)°. The Yb3+ ions are surrounded by oxygen leading to YbO8 coordination polyhedra while atomic disorder is observed for the cations Ba2+ and K+, statistically sharing their positions inside 8-vertex coordination polyhedra. The Raman spectrum confirms the presence of distorted MoO4 tetrahedra for the BaKYb(MoO4)3 molybdate. Investigation of its magnetic properties was undertaken in order to check whether a magnetic ordering occurs at low temperature.