Crystal Growth and Physical Properties of Sr4Co3O7.5+xCl2 Single Crystals (x ∼ 0.14)

We report on the single crystal growth and physical properties of the triple-layer cobalt oxychloride Sr 4 Co 3 O 7 . 5 + x Cl 2 (x∼ 0.14) with 4-3-10 Ruddlesden–Popper type structure that was synthesized by a KCl-SrCl 2 flux method. The crystal structure was determined by means of single crystal X-ray diffraction. In this quasi two dimensional (2D) material two pyramidal CoO 5 layers and a central Co oxide layer with random oxygen deficiencies are forming the layered Co oxide blocks. These blocks are separated by Cl − -ions which are interacting via Van der Waals forces, thus, enhancing the quasi 2D nature of this compound. The soft X-ray absorption spectra at the Co-L 2 , 3 edge and O-K edge indicate that Co ions are in high spin +3 state which is in agreement with the single crystal X-ray diffraction measurements that indicate basically pyramidal oxygen environments for the Co 3 + ions in this compound.