Novel phosphate halides BaMnIII[PO4]FCl and BaMnIII[PO4]F2: Effects of mixed halides on crystal structures and magnetic properties

• Two novel phosphate halides BaMn[PO4]FCl and BaMn[PO4]F2 have been prepared.
• These new compounds adopt different types of layered structures.
• They have different molecular vibration modes and thermal stabilities.
• BaMn[PO4]FCl has weaker antiferromagnetic interactions than BaMn[PO4]F2.
• The former adopts isolated octahedra whereas the latter adopts octahedral chains.

Two new phosphate halides BaMnIII[PO4]FCl (1) and BaMnIII[PO4]F2 (2), have been synthesized under hydrothermal conditions. Structural characterizations show that both new compounds adopt layered structures but with different polyhedral linkages. Introduction of Cl into Compound (1) results in isolated hemimorphic [MnO4FCl] octahedra, different from the chain of [MnO4F2]/[MnO2F4] octahedra in Compound (2). These compounds have significantly different molecular vibration modes and thermal stabilities. Magnetic measurements reveal that Compound (2) has larger antiferromagnetic interactions than Compound (1), because the former has strong interactions between Mn3+-Mn3+ ions within corner-shared Mn3+-octahedral chains whereas the latter only possesses isolated Mn3+-octahedra. Both compounds transform to a new orthorhombic compound BaMnII(PO4)F (3) after thermal decomposition.

The large radius of Cl- ions makesBaMnIII[PO4]FCl to adopt isolated [MnO4FCl] rather than corner-sharing octahedra as observed in BaMnIII[PO4]F2.Figure optionsDownload as PowerPoint slide