Structure and antiferromagnetic properties of a mixed valent molybdeno monophosphate of lithium

A lithium mixed valent molybdenophosphate LiMo2VMoVI P3O16 has been synthesized for the first time. This phase isotypic to NaMo3P3O16 is triclinic with a = 6.374(1)Å, b = 7.709(1)Å, c = 12.529(1)Å, α = 80.03(1) ∘, β = 77.62(1) ∘, γ = 81.80(1) ∘; its framework very similar to that of the sodium phase, is characterized by monophosphate group linked to MoO6 octahedra and MoO5 trigonal bipyramids, occupied by Mo(V) and Mo(VI) respectively. It differs from the Na and Ag phases by the position of the lithium, that is located near the basal plane of a tetragonal pyramid. The investigation of its magnetic properties, shows that LiMo2VMoVIP3O16, exhibits an antiferromagnetic ordering below 100K, which can be interpreted as the result of two opposite orientations of the Mo(V) spins on the two octahedral sites, Mo(1) and Mo(2).