Weak ferromagnetism with very large canting in a chiral lattice: (pyrimidine)2FeCl2

The transition metal coordination compound (pyrimidine)2FeCl2 crystallizes in a chiral lattice, space group I 4_1 2 2 (or I4_3 2 2). Combined magnetization, Mossbauer spectroscopy and powder neutron diffraction studies reveal that it is a canted antiferromagnet below T_N = 6.4 K with an unusually large canting of the magnetic moments of 14 deg. from their general antiferromagnetic alignment, one of the largest reported to date. This results in weak ferromagnetism with a ferromagnetic component of 1 mu_B. The large canting is due to the interplay between the antiferromagnetic exchange interaction and the local single-ion anisotropy in the chiral lattice. The magnetically ordered structure of (pyrimidine)2FeCl2, however, is not chiral. The implications of these findings for the search of molecule based materials exhibiting chiral magnetic ordering is discussed.Comment: 6 pages, 5 figure

Heteromorphic Colonies Associated with Ring Formation

A striking phenomenon was observed in heavily seeded dilution plates of the bean-halo-blight organism, Phytomonas medicaginis (Sackett) Bergey et al. var. phaseolicola Burkholder. A con-voluted variant of this species (plate I, fig. 1) characterized by colonies with rubbery consistency, rolled margins, and depressed centers was isolated from a sector occurring in a smooth colony. Broth cultures of the variant produced no colonies resembling the original smooth form, but gave rise to two distinct kinds of convoluted colonies on agar plates. Colonies of one form occu-pied an irregularly shaped circular area that varied in diameter from several centimeters to almost the width of the plate. The outer edge of this area consisted of colonies that were greatly enlarged so that a raised ring was formed. The other colony-form occupied the entire area outside the raised ring. Colonies within the ring were translucent, semi-fluid, and lobed, as though by renewed growth from points on their peripheries. Those that made up the ring itself were translucent, semi-fluid, and greatly enlarged. Colonies outside the ring were white in color and rubbery in consistency. Microscopically, the colonies inside the ring were translucent, colorless, and composed of elongated, thin, non-capsulated cells. Those outside the ring were opaque, light brown, and composed of short, plump, capsulated cells. Bacteria from all colonies re-acted negatively to Gram's stain. A study of the ring showed that, while it usually developed near the center of the plate, it sometimes occurred towards one side

Grass Seedling Emergence and Survival after Treatment with Fungicides

Thiram, Captan and Semesan were used to treat seeds of intermediate wheatgrass, tall oatgrass and smooth brome, seeded in spring and fall for 5 years, and to treat seeds of crested and intermediate wheatgrasses seeded for 3 years at a second location. The same fungicides were used to treat grass seeds at 3 rates in two studies in the greenhouse. Kind or rate of fungicide treatment did not significantly influence seedling emergence in the greenhouse. Averaging the two field areas, Thiram treatments gave significant increases over the check of 14% in emergence and 20% in survival. Captan treatments gave significant increases of 12% in emergence and survival. Semesan increases were not significantly better than the check.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202