The structural and electronic properties of the ru(v) perovskites ba₂laru_0.5sb_0.5o₆ and ba₂taru_0.5na_0.5o₆

The compounds Ba₂LaRu_0.5Sb_0.5O₆ and Ba₂TaRu_0.5Na_0.5O₆ have been used to study the magnetic properties of Ru(V) when present in low concentrations in a mixed metal oxide. Ba₂TaRu_0.5Na_0.5O₆ is a simple cubic perovskite (a₀ = 4.1321(5) Å) with a random distribution of Ta, Ru, and Na over the six-coordinate sites and a magnetic susceptibility that follows the Curie-Weiss Law (μ_eff 3.44 μ_B, θ = - 142 K). Neutron powder diffraction has been used to show that Ba₂LaRu_0.5Sb_0.5O₆ is a distorted perovskite (space group 1-1, a = 6.0741(5), b 6.0895(5), c = 8.6124(9) Å, α = 89.93(1), β = 90.39(1), γ = 89.91(1)°) with a 1:1 ordered arrangement of La and Ru/Sb atoms over the six-coordinate sites. Again the magnetic susceptibility follows a Curie-Weiss law (μ_eff 3.78 μ_B, θ = -170 K). These results are considered in the light of the magnetic susceptibility of Ba₂LaRuO₆ (μ_eff = 4.00 μ_B, θ = -304 K).