The transition metal orthophosphates Na2 M 2Fe(PO4)3 (M = Co, Ni) crystallize in an alluaudite-type structure. The chains characterizing the alluaudite structure are then built up from [M 2O10] units alternating with [FeO6] octa­hedra.

The leaf essential oils from two samples of Lippia multiflora (Verbenaceae) collected in two localities of Gabon were obtained by hydrodistillation and analysed by GC and GC-MS. The oils differed completely in their chemical composition: the former was characterized by a high amount of ipsdienone (54.6%), (Z)-and (E)-ocimenones (20.3%); (E)-β β β β β-farnesene (7.4%) and β β β β β-caryophyllene (4.6%) were the main components of the sesquiterpenoid fraction; the latter consisted mainly of thymol (41.9%), thymyl acetate (21.2%), p-cymene (9.8%) and carvacrol (7.2%), which allows differenciation between two chemotypes. The antioxidant and antiradical activities of both samples were evaluated comparatively to those of reference compounds (BHT, thymol and carvacrol). An interesting antioxidant activity was found for the second chemotype as expected on the basis of its phenolic compounds content.

No abstract

Reaction of W(CO)6 with Se4(Sb2F11)2 in SO2 results in the formation of a compound formulated as W2(CO),&e42+ (SbF6-l2 the dimeric cation geometry of which has been established by X-ray crystal structure determination.

Water distilled essential oils from leaves of Plectranthus tenuicaulis (Hook. f.) J. K. Morton collected in Gabon were analyzed using GC-FID and GC-MS. The main constituent, unusual within the genus Plectranthus, was isolated and formally identified as being the (+)-(R)enantiomer of (E)-6,7-epoxyocimene [(E)-myroxide]. This enantiomer, which represents about 75% of the essential oil, has been previously identified as a pheromone emitted by the male fruit-spotting bug Amblypelta nitida; this insect is responsible of destruction of most fruit crops in tropical and subtropical areas. The potential application of P. tenuicaulis essential oil in crop protection programs is discussed and the atypical chemical profile of the gabonese essential oil is compared with those previously reported in the genus Plectranthus (or Coleus).