Crystal growth, thermal, optical, magnetic and electrochemical properties of Mo2Ta2O11

Single crystals of the transition metal oxide Mo 2 Ta 2 O 11 were grown for the first time using molten flux synthesis. The compound crystalizes in the trigonal space group R 3 ‾ m (no. 166) with lattice parameters a = b = 5.6267(1) Å and c = 25.1424(6) Å and a unit cell volume of 689.36(3) Å 3 . The structure of Mo 2 Ta 2 O 11 is composed of alternating layers of TaO 6 octahedra and MoO 4 tetrahedra connected via corner-sharing. CaH 2 was used to achieve a partial low temperature reduction of Mo 2 Ta 2 O 11 . The electrochemical lithiation of polycrystalline Mo 2 Ta 2 O 11 was also investigated for the first time. Mo 2 Ta 2 O 11 underwent a structural rearrangement while maintaining a reversible capacity of ∼150 mAh/g. • Mo 2 Ta 2 O 11 was synthesized via molten flux crystal growth yielding high quality single crystals. • Optical investigation reveals the semiconducting nature of the compound. • A low temperature reduction in the compound gave rise to paramagnetic behavior. • Mo 2 Ta 2 O 11 exhibits a reversible lithiation capacity of 167.6 mAh/g, however, accompanied by a loss of structural integrity.