| Institution: | 1. Department of Physics & Astronomy, State University of New York, Stony Brook, NY, 11794-380 USA
Current Address: X-ray Science Division, Argonne National Laboratory, Lemont, IL, 60439 USA;2. Department of Physics & Astronomy, State University of New York, Stony Brook, NY, 11794-380 USA;3. Department of Chemistry, University of Utah, Salt Lake City, UT, 84112-0850 USA |
| Abstract: | The reaction of MnII(O2CMe)2 and NaCN or LiCN in water forms a light green insoluble material. Structural solution and Rietveld refinement of high-resolution synchrotron powder diffraction data for this unprecedented, complicated compound of previously unknown composition revealed a new alkali-free ordered structural motif with MnII4(μ3-OH)4]4+ cubes and octahedral MnII(CN)6]4? ions interconnected in 3D by MnII-N≡C-MnII linkages. The composition is {MnII(OH2)3]MnII(OH2)]3}(μ3-OH)4]MnII(μ-CN)2(CN)4] ? H2O=MnII4(μ3-OH)4(OH2)6]MnII(μ-CN)2(CN)4] ? H2O, which is further simplified to Mn4(OH)4]Mn(CN)6](OH2)7 ( 1 ). 1 has four high-spin (S=5/2) MnII sites that are antiferromagnetically coupled within the cube and are antiferromagnetically coupled to six low-spin (S=1/2) octahedral MnII(CN)6]4? ions. Above 40 K the magnetic susceptibility, χ(T), can be fitted to the Curie–Weiss expression, χ ∝(T?θ)?1, with θ=?13.4 K, indicative of significant antiferromagnetic coupling and 1 orders as an antiferromagnet at Tc=7.8 K. |
