Through the cooperation of the Canada Centre for Mineral and Energy Technology (CANNET) and the Land Resource Research Institute of Agriculture Canada, four soil samples have been prepared as compositional reference materials: a clayey soil, a sandy podzolic B horizon with a high organic content, a calcareous till, and a chernozemic A horizon. All have a wide range of compositions. Bulk samples of 180 to 280 kg of each were dried, ground to minus 74 pm, blended, tested for homogeneity and bottled in 200-g units. Thirty-six laboratories participated in the certification program by providing analytical results for 1 to 25 constituents for each of two bottles of each sample. Based on statistical analyses of the data, the four reference samples were certified for Al, Fe, Mn, K, Zn, Cu, Cr and Pb, and one or more were certified for Si, Na, Mg, Ca, P, Ti, Hg, Ni, Sr and V. Preliminary data were obtained for another 47 elements.

Optical absorption measurements show that the pleochroism of erythrite is due to variations in the main absorption envelope in the 400 to 600-mn region as crystallographically oriented sections are rotated in linearly polarized light. The absorption envelope arises from the 4T1 (F) --> 4 T, (P) transition, with contributions from transitions derived from 2G and 'H levels, in octahedrally coordinated Coil- ions, of which there are two kinds (Coi and Con) in erythrite. The pleochroism is related to the interaction of the electric vector of light with electrons located in specific t2g orbital lobes of ions in the Coi and Coil sites. The validity of the present interpretation rests on the assumptions that erythrite is isostructural with vivianite and symplesite and that the principal optical directions are essentially coincident with the "molecular axes" of the Co2+-bearing octahedra.

By the use of elementary ligand field theory to interpret the absorption spectra of complexes formed in the copper(II)–1,10-phenanthrolene (Phen) system in an acetone medium, it has been shown that the mono-Phen complex is of approximately octahedral symmetry and the bis-Phen complex probably has a trigonal bipyramidal structure. At high Phen concentration, a tris-complex is formed that is probably trigonally distorted from octahedral symmetry. The results of the present work suggest that the "pentammine effect" observed in spectra of the copper(II)–ammonia complex is due to the formation of a trigonal bipyramidal complex.

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The unpolariacd optical absorption spectra of the sheet silicate minerals muscovitey Bepidslite, and fuchsite have been examined. The spectra, interpreted on the basis of ligand field theory, indicate that all three minerals contain Fe3-' and possibly Ti3-' in octahedral sites. In addition, niuscovite is shown to contain octahedrally coordinated FezT, lepictolite octahedral Fez-' and Mn2'-, and fuchsite octahedral Cr3yS No evidence was found for transition metals in tetrahedral sites.Some comments are made on the similarity of the spectra of certain of the tPansition metal ions in several classes of minerals. This leads t s the speculatioia that the cations Fdc, Mn2 I-, and Cr3+ may tend to 'mold' their immediate surroundings. Introductioning cation, its valence state, and the approximate It is well known that transition metal ions, geometry of the site in which it is accommodated present as principal constituents or more fre-in the crystal lattice. quently as minor ones, profoundly iniluence the To explain unempirically the origins of color optical properties of many silicate minerals. and pleochroism it is necessary to have a