The crystal structure of the bismuth(111) complex with (+)-tartaric acid, ammonium aquabis[(+)tartrato(2-)]bismuthate(111) hydrate, has been determined by X-ray methods and refined to a residual R 0.020 for 1288 observed reflections. Crystals are orthorhombic, space group P 212121 with Z 4 in a cell of dimensions a 7.4712 (4), b 10.856(1), c 17.609(3) A. Each nine-coordinate MOQ bismuth centre comprises three bidentate a-hydroxy carboxy residues from two tartrato(2-) ligands (with one bridging), an asymmetric bidentate carboxylato(0,O ') group, and a water. The Bi-0 range is 2.372(7)-2.738(6) .k [mean 2.509(6) A]. The resultant structure is a linear polymer which is stabilized by extensive hydrogen-bonding interactions. Mlcks, R. H., (Ed.) 'Essentials of Materia Medica Pharmacology and Therapeutics' 4th Edn (

A series of silver(I) complexes with the unsaturated isomeric dicarboxylic acids, maleic and fumaric, has been prepared and the structures of three of these, silver(I) hydrogen maleate, (1), silver(I) maleate, (2) and silver(I) fumarate, (3), were determined by X-ray diffraction. All three structures are polymeric, with (1) and (2) based on bis(carboxylato-

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The crystal structures of four analogues of the auxin herbicide series, including inactive examples, have been determined by X-ray diffraction methods. The compounds (2-isopropy1phenoxy)acetic acid (1), (4-fluorophenoxy)acetic acid (2) and (2,4-dichloro-5-fluorophenoxy)acetic acid (3) are from the phenoxyalkanoic acid series while (indol-3-ylthio)acetic acid (4) is the sulfur analogue of the natural plant hormone indole-3-acetic acid. All examples exist as hydrogen-bonded cyclic dimers [O…O, 2.640(7), 2.62(1), 2.637(4) and 2.665(4) � for (1)-(4), respectively]. Compounds (1) and (2) are essentially planar while compounds (3) and (4) have side chains anticlinally related to the ring systems, similar to (2,4-dich1orophenoxy)acetic acid and to indole-3-acetic acid.

The crystal structures of the silver(I) complexes with phenoxyacetic acid and 4-fluorophenoxyacetic acid, catena-[ bis-μ-(phenoxyacetato-O,O′)- disiver (I)] (1) and bis [ bis-μ(4-fluorophenoxyacetato-O,O′)-{ aquasilver (I)}] (2) have been determined and refined to residuals R 0.068 and 0.036 respectively for 1783 and 2549 observed reflections. Both structures are based on similar bis ( carboxylato -O,O′) bridged dimers with Ag-Ag 2.866(2)Ǻ (1) and 2.836(2)Ǻ (2). However, (1) forms a step polymer through terminal oxygens [Ag-O 2.417, 2.443(9)Ǻ], while (2) is a discrete centrosymmetric tetramer with a water molecule on each of the four silver atoms [Ag- Ow 2.499(4)Ǻ], and an Ag-O bridge distance of 2.498(4)Ǻ. This results in triangular coordination about one silver and tetrahedral about the second. Experimental data indicate that anhydrous silver(I) 4-chlorophenoxyacetate (3) is similar to complex (1).