Structural, magnetic and mossbauer studies of the molecular ferromagnet compounds NBu/sub 4/[C/sub 2/O/sub 4/)/sub 3/] (Bu = (CH/sub 2/)/sub 3/CH/sub 3, M = Mn, Fe)

Summary form only given. Room temperature X-ray single crystal study of the Mn member of the recently discovered molecular-based ferromagnet compound series NBu/sub 4/ [MCr (C/sub 2/O/sub 4//sub 3/], (M = Mn, Fe, Ni, Co, Cu) [1] has revealted a hexagonal structure, space group R3c, 1=2=9,414 (5)A, c=53.662(6) A, built from oxalate-bridged metals ions layers separated by NBU/sub 4/+ layers. It is suggested that the anisotropic interaction of butyl groups with neighboring atoms of the metal oxalate network results in ordered arrangement of metallic cations which in turn ensures both in- and interlayer ferromagnetic interactions. Single crystal dc magnetization studies at 4.5 K have shown the easy magnetization direction to be along the crystal c-axis. On the other hand, from Mossbauer studies of M=Fe composition the magnetic axis is confined to the c-plane with strong out-of-plane anisotropy. Anomalous temperature behavior of Fe2+ ions mean square displacement along the c-axis is related to the orientational disorder of butyl groups above ca. 200 K.