grown directly from the melt and prepared by solid-state reactions, respectively, at various
temperatures between 1598 K and 1983 K. The chemical composition of the crystals was
confirmed by wavelength-dispersive X-ray spectroscopy, and the crystal structures were
determined using single-crystal X-ray diffraction. Structural investigations of the isostructural
compounds resulted in the following basic crystallographic data: monoclinic symmetry …