Dielectric properties depend on the crystal structure of perovskite-type RbTaO synthesized at high pressure.

We successfully synthesized perovskite-type RbTaO at 1173 K under 4 GPa. RbTaO crystalized as a cubic system (3̄ space group (SG), = 4.04108(3) Å) at 300 K in contrast to the orthorhombic perovskite-type RbNbO prepared under the same conditions.

Crystal structure and properties of perovskite-type rubidium niobate, a high-pressure phase of RbNbO.

We synthesized a perovskite-type RbNbO at 1173 K and 4 GPa from non-perovskite RbNbO and investigated its crystal structure and properties towards ferroelectric material design. Single-crystal X-ray diffraction analysis revealed an orthorhombic cell in the perovskite-type structure (space group 2, no. 38) with = 3.