Synthesis and Crystal Structure of the New High‐Pressure Phase CdB 2 O 4

The use of high‐pressure/high‐temperature conditions (7.5 GPa and 1100 °C; Walker‐type multianvil apparatus) led to the synthesis of a new cadmium borate CdB 2 O 4 , starting from stoichiometric mixtures of the oxides. The crystal structure was determined on the basis of single crystal X‐ray diffraction data, to reveal the hexagonal space group P 6 3 with a =885.2(2), c =716.72(8) pm, Z =8, R 1 =0.0178, and wR 2 =0.0388 (all data). CdB 2 O 4 is built up from interconnected layers of BO 4 ‐tetrahedra and exhibits for the first time the basic structure of a family of compounds, represented by BaGa 2 O 4 , KAlSiO 4 , KGeAlO 4 , KCoPO 4 , CaP 2 N 4 and the recently discovered SrP 2 N 4 . The lack of superstructure ordering in CdB 2 O 4 was confirmed by electron diffraction. Additionally, a BOB angle of 180° was found in this borate for the first time.