J. C. Boivin

The bimevox series: A new family of high performances oxide ion conductors

Abstract A new family of oxygen anionic conductors, exhibiting high performances at low temperature, has been prepared and characterized. They derive from Bi4V2O11 by partial substitution of vanadium by other metallic ions (BIMEVOX). Results dealing with the copper substituant (BICUVOX) are detailed.

Electrochemical characterization of BIMEVOX oxide-ion conductors

Partial substitution of metals such as Cu or Zn for vanadium in Bi4V2O11 leads to materials exhibiting high anionic conductivities at temperatures as low as 500 K. These materials have been characterized electrochemically for use as potential solid electrolytes in potentiometric and amperometric oxygen sensors. Their electronic conductivities are significant.

Ionic conductor membrane for oxygen separation

The suitability of a bismuth-lead mixed oxide, Bi 0.571 Pb 0.428 O 1.285 , for oxygen separation at moderate temperature has been evaluated. Mechanical properties of the solid electrolyte have been enhanced by incorporating ZrO 2 into the starting material. Several metals and oxides were used as the electrode material. The optimized membrane is able to operate continuously up to 300 mA cm −2 at 600°C.

N-[(Ethyl-1 pyrrolidinyl-2) méthyl] méthoxy-2 sulfamoyl-5 benzamide (sulpiride)

CIsH23N304S, triclinic, P i , Z = 2, a = 11.173(2), b = 9.082(2), c = l l . 2 9 5 ( 2 ) / k , a = 90 .5 (1 ) , f l = 130.9(1), 7 = 100.1 (1)°; De= 1.34, D m = 1.34 Mg m -3. The structure was solved by direct methods and refined by a full-matrix least-squares procedure to a final R value of 0.077 for 1622 observed 0567-7408/81/040981-04501.00 reflexions using Cu Ka radiation. The molecule of sulpiride is in extended configuration. A partial disorder was observed around the amide function. Hydrogen bonds occur between the H atoms of the sulfamoyl group and the amide function and the pyrrolidinyl group of two different molecules.

Electrical properties of the A-La2O3 type Bi1−xPbxF2xyO1.5−0.5x−xy solid solution

Abstract The electrical properties of a trigonal, A-La 2 O 3 type, bismuth lead oxyfluoride solid solution have been systematically investigated by means of impedance spectroscopy and dc polarization techniques. The fluorine conductivity which corresponds to a three-dimensional process, progressively increases with the number of fluoride ions ( n F− /cell) as long as the number of the corresponding oxide ions ( n O 2− /cell) remains significantly lower than 2. The total conductivity always exhibits a min n O 2− /cell = 2. For higher n O 2− /cell values, whereas the migration process becomes o conductivity is observed, accompanied by a sudden enhancement of the polarization current. It could be due to an oxide contribution to the migration mechanism, rather than to an electronic contribution. This phenomenon is accentuated by the decrease of the ordering tendency which has been shown to be maximum for samples with composition corresponding to n O 2− /cell = 2.

High oxygen ion conduction in a bismuth oxide - cadmium oxide phase: Conductivity and transport number measurements ; Structural investigations

Abstract High oxide ion conduction has been found in the oxygen-deficient solid solution Bi(1−x) Cd (x) O(1.5−x/2) (σ=0.77 (Ω.cm) −1 at 680°C, for x=0.21). Its homogeneity range was determined to be 0.11 ⩽ x ⩽ 0.25 by means of DT and X-ray analyses. The anionic character of the conductivity has been confirmed by transport number measurements. The structure consists of a network of cations located on the two-fold position of the b.c.c cell (a=4.281(1) A for x=0.21) , while the oxide ions are statistically distributed over the twelve tetrahedral sites of the cube faces.

Electrical properties and high temperature crystal structure of the bismuth lead oxyfluoride: BiPbO2F

The electrical properties of the BiPbO 2 F conductor were examined by means of impedance spectroscopy and de polarization techniques. Fluorine was shown to be the main mobile species. Crystal structure investigations were performed using X-ray single crystal and neutron powder diffractions. Cations are localized in the 2d site of the A−La 2 O 3 type structure while anions are distributed over the 1a, 2c, 6i and 6h positions of the P3ml space group. According to the fluorine location confirmed by a 19 F NMR experiment, a fluorine migration mechanism is proposed.

Crystal structure determination and stability of copper (II) hydroxymethylphosphonate dihydrate

Abstract Copper(II) hydroxymethylphosphonate dihydrate HOCH2PO3Cu, 2 H2O is triclinic : a = 10.870(3), b = 5.130(2), c = 5.628(2) A , α = 96.6(1)β = 114.6(1), γ = 97.2(1)°, S.G. Pl, Z = 2. The structure was solved by the heavy atom method and full matrix least-squares refinement to a final R value = 0.035. The two Cu atoms in the cell are structurally different : Cu(1) is octahedrally surrounded by four phosphonate oxygen atoms and two hydroxyl groups. Cu(1)O6 octahedra chains extend along [010]. Cu(2) is coordinated to two phosphonate oxygen atoms and four water molecules. Cu(2)O6 octahedra link the chains to form infinite layers parallel to [101]. These layers are held together by means of hydrogen bonds. The right formula must therefore be written [Cu(HOCH2PO3)2] Cu, 4 H2O. The greater stability of the octahedral configuration versus the t.b.p. one and the occurence of bonding between copper atoms and hydroxyl groups can explain the increase of stability observed from methylphosphonate to hydroxymethylphosphonate copper complexes.

Structure du chlorhydrate de la méthyl-3 (amino-2 ethyl)-6 dihydro-2,3 benzoxazole-1,3 one-2

CIoH~aN202+.C1 -, M r = 228.5, triclinic, P1, a = 2 1 . 2 2 6 ( 3 ) , b = 5 . 7 8 5 ( 1 ) , c = 4 .491(1) /~, a = 94.53 (5), f l = 90.05 (5), y = 94.92 (5) °, V = 5 5 6 . 2 A 3, Z = 2 , D x = l . 3 8 g c m -3, M o K a , 2 = 0.7107/~, # = 3.4 cm -1, F(000) = 274, T = 298 K, wR ~ 0.055 for 1732 independent reflexions [I > 3o(1)]. The molecule is in an extended configuration. The crystal cohesion is enhanced by three hydrogen bonds between the C1 atom and three N atoms belonging to different molecules. The molecular conformation is compared with that of other dopaminergic or