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Single crystals of β-KCoFe(PO4)2, potassium cobalt(II) iron(III) bis(orthophosphate), were grown from the melt under atmospheric conditions. This phosphate crystallizes isotypically with KZnFe(PO4)2 in space group C2/c, adopting a zeolite-ABW type of structure. The structure of the present phosphate is distinguished by an occupational disorder of the two transitionmetal sites with ratios Fe:Co of 0.5725:0.4275 for the first and 0.4275:0.5725 for the second site. In the crystal structure, PO4 and (Co,Fe)O4 tetrahedra are linked through vertices to form elliptical rings with the sequence DDDDUUUU of up (U) and down (D) pointing vertices. Each eight-membered ring is surrounded by four other rings of the same type, delimiting interstices with rectangular shape. This arrangement leads to the formation of [(Co/Fe)(PO4)]-∞ sheets parallel to (001). Stacking of the sheets into a threedimensional framework results in the formation of two types of channels. The first one is occupied by potassium cations, whereas the second one remains vacant. Calculations of bond-valence sums and charge distribution were used to confirm the structure model. [ABSTRACT FROM AUTHOR]

The new silver-, cobalt- and iron-based phosphate, silver cobalt iron tris(orthophosphate), Ag1.655Co1.64Fe1.36(PO4)³, was synthesized by solid-state reactions. Its structure is isotypic to that of Na2Co2Fe(PO4)3, and belongs to the alluaudite family, with a partial cationic disorder, the AgI atoms being located on an inversion centre and twofold rotation axis sites (Wyckoff positions 4a and 4e), with partial occupancies of 0.885 (2) and 0.7688 (19), respectively. One of the two P atoms in the asymmetric unit completely fills one 4e site while the Co and Fe atoms fill another 4e site, with partial occupancies of 0.86 (5) and 0.14 (5), respectively. The remaining Co2+ and Fe3+ cations are distributed on a general position, 8f, in a 0.39 (4):0.61 (4) ratio. All O atoms and the other P atoms are in general positions. The structure is built up from zigzag chains of edge-sharing [MO6] (M = Fe/Co) octahedra stacked parallel to [101]. These chains are linked together through PO4 tetrahedra, forming polyhedral sheets perpendicular to [010]. The resulting framework displays two types of channels running along [001], in which the AgI atoms (coordination number eight) are located. [ABSTRACT FROM AUTHOR]

The title compound, SrCo2Fe(PO4)3, has been synthesized by a solid-state reaction. It crystallizes with the α-CrPO4 type structure. In this structure, all atoms are on special positions of the Imma space group, except for two O atoms which are located on general positions. The three-dimensional network in the crystal structure is made up of two types of layers stacked normal to (100). The first layer is built from two edge-sharing CoO6 octahedra, leading to the formation of Co2O10 dimers that are connected to two PO4 tetrahedra by a common edge and corners. The second layer results from apex-sharing FeO6 octahedra and PO4 tetrahedra, which form linear chains alternating with a zigzag chain of SrII cations. These layers are linked together by common vertices of PO4 tetrahedra and FeO6 octahedra to form an open three-dimensional framework that delimits two types of channels parallel to [100] and [010] where the SrII cations are located. Each SrII cation is surrounded by eight O atoms. [ABSTRACT FROM AUTHOR]

The title compound, SrCo2Fe(PO4)3, has been synthesized by a solid-state reaction. It crystallizes with the α-CrPO4 type structure. In this structure, all atoms are on special positions of the Imma space group, except for two O atoms which are located on general positions. The three-dimensional network in the crystal structure is made up of two types of layers stacked normal to (100). The first layer is built from two edge-sharing CoO6 octahedra, leading to the formation of Co2O10 dimers that are connected to two PO4 tetrahedra by a common edge and corners. The second layer results from apex-sharing FeO6 octahedra and PO4 tetrahedra, which form linear chains alternating with a zigzag chain of SrII cations. These layers are linked together by common vertices of PO4 tetrahedra and FeO6 octahedra to form an open three-dimensional framework that delimits two types of channels parallel to [100] and [010] where the SrII cations are located. Each SrII cation is surrounded by eight O atoms. [ABSTRACT FROM AUTHOR]

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-farnesene (7.4%) and 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. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Single crystals of the title compound are prepared by solid state reaction of a 1:2:1:3 molar mixture of Sr, Co, and Fe nitrates along with NH4H2PO4 (Pt crucible, 1343 K; cooling to 273 K at a rate of 5 K/h). [ABSTRACT FROM AUTHOR]

Single crystals of β-KCoFe(PO4)2, potassium cobalt(II) iron(III) bis(orthophosphate), were grown from the melt under atmospheric conditions. This phosphate crystallizes isotypically with KZnFe(PO4)2 in space group C2/c, adopting a zeolite-ABW type of structure. The structure of the present phosphate is distinguished by an occupational disorder of the two transitionmetal sites with ratios Fe:Co of 0.5725:0.4275 for the first and 0.4275:0.5725 for the second site. In the crystal structure, PO4 and (Co,Fe)O4 tetrahedra are linked through vertices to form elliptical rings with the sequence DDDDUUUU of up (U) and down (D) pointing vertices. Each eight-membered ring is surrounded by four other rings of the same type, delimiting interstices with rectangular shape. This arrangement leads to the formation of [(Co/Fe)(PO4)]-∞ sheets parallel to (001). Stacking of the sheets into a threedimensional framework results in the formation of two types of channels. The first one is occupied by potassium cations, whereas the second one remains vacant. Calculations of bond-valence sums and charge distribution were used to confirm the structure model. [ABSTRACT FROM AUTHOR]

The title compound, SrCo2Fe(PO4)3, has been synthesized by a solid-state reaction. It crystallizes with the α-CrPO4 type structure. In this structure, all atoms are on special positions of the Imma space group, except for two O atoms which are located on general positions. The three-dimensional network in the crystal structure is made up of two types of layers stacked normal to (100). The first layer is built from two edge-sharing CoO6 octa-hedra, leading to the formation of Co2O10 dimers that are connected to two PO4 tetra-hedra by a common edge and corners. The second layer results from apex-sharing FeO6 octa-hedra and PO4 tetra-hedra, which form linear chains alternating with a zigzag chain of Sr(II) cations. These layers are linked together by common vertices of PO4 tetra-hedra and FeO6 octa-hedra to form an open three-dimensional framework that delimits two types of channels parallel to [100] and [010] where the Sr(II) cations are located. Each Sr(II) cation is surrounded by eight O atoms.

The title compound, Na2Co2Fe(PO4)3, was synthesized by a solid-state reaction. This new stoichiometric phase crystallizes in an alluaudite-like structure. In this structure, all atoms are in general positions except for four atoms which are located at the special positions of the C2/c space group. One Co atom, one P and one Na atom are all located on Wyckoff position 4e (2), while the second Na atom is located on an inversion centre 4a (-1). The other Co and Fe atoms occupy a general position with a statistical distribution. The open framework results from [(Co,Fe)2O10] units of edge-sharing [(Co,Fe)O6] octa-hedra, which alternate with [CoO6] octa-hedra that form infinite chains running along the [10-1] direction. These chains are linked together through PO4 tetra-hedra by the sharing of vertices so as to build layers perpendicular to [010]. The three-dimensional framework is accomplished by the stacking of these layers, leading to the formation of two types of tunnels parallel to [010] in which the Na(+) cations are located, each cation being surrounded by eight O atoms.