- New ternary and quaternary barium nitride halides; Synthesis and crystal chemistry
-
New ternary and quaternary nitride halides, Ba2N(X,X′) (X = F, Cl, Br; X′ = Br, I), have been synthesized from the high temperature reactions of barium subnitride with the respective barium halides under an inert atmosphere. The former include the first fully characterized barium nitride halides for X other than F, and the latter are the first examples of barium nitride mixed halides. The variation in structure with composition has been investigated by powder X-ray and powder neutron diffraction techniques. The heavier ternary and quaternary nitride halides (X, X′ = Cl, Br, I) crystallize in the hexagonal space group R3m, with the anti-α-NaFeO2 structure. Ba2NF forms with both an anti-α-NaFeO2 structure, in which N3- and F - are ordered and an anion-disordered simple rock salt structure. The hexagonal polymorph of Ba2NF is the only example to date of a nitride fluoride adopting this layered structure. Both the ternary and the quaternary compounds display very weak, temperature independent paramagnetism.
- Bailey, Andrew S.,Hughes, Robert W.,Hubberstey, Peter,Ritter, Clemens,Smith, Ronald I.,Gregory, Duncan H.
-
-
Read Online
- Synthesis of nanocomposites comprising iron and barium hexaferrites
-
Composites of nanometre-sized α-iron and barium hexaferrite phases, respectively, have been synthesized by the ceramic processing route. Pure barium hexaferrite (BaO·6Fe2O3) was first of all prepared by calcinations of the precursor oxides at a maximum temperature of 1200°C for 4 h. By subjecting the resulting powder having particle size of the order of 1 μm to a reduction treatment in the temperature range 500-650°C for a period varying from 10 to 15 min it was possible to obtain a composite consisting of nanosized barium hexaferrite and α-Fe. At reduction temperature of 650°C for a period greater than 15 min all the ferrite phase was converted to α-Fe and Ba - the particle sizes being 59. 4 and 43.6 nm, respectively. These conclusions are based on X-ray diffraction and Mossbauer studies of different samples. During reduction H+ ions are introduced into the hexaferrite crystallite. It is believed that due to a tensile stress the crystals are broken up into smaller dimensions and the reduction brings about the growth of nanosized α-Fe and barium, respectively, around the hexaferrite particles. Magnetic measurements show coercivity values for the reduced samples in the range 120-440 Oe and saturation magnetization varying from 158 to 53.7 emu/g. These values have been ascribed to the formation and growth of α-Fe particles as the reduction treatment is increased. By heating the nanocomposites at a temperature of 1000°C for 1 h in ordinary atmosphere it was found that they were reconverted to the barium hexaferrite phase with a particle size ~182.3 nm. The reaction described in this study is thus reversible.
- Pal,Bid,Pradhan,Nath,Das,Chakravorty
-
-
Read Online
- Ba21Ge2O5H24 and Related Phases. A Corrected Structure Type and Composition for a Zintl Phase Stabilized by Hydrogen
-
Syntheses of the so-called suboxide phases Ba21T2O5 (T = Ge, Si, Ga, In, Tl) are achieved only in the presence of hydrogen. The heavy-atom structure of Ba21Ge2O5H24 at room temperature was redetermined by single-crystal X-ray diffraction and found to be primitive trigonal symmetry (P3121 (No. 152), Z = 6, a = 14,4227(5) ?, c = 35.332(3) ?) instead of the previously refined cubic (Fd3?m) result. The change greatly improves the heavy-atom parameters. Twenty-four independent deuterium atoms have also been located by time-of-flight neutron diffraction, The structure contains Ba2+ cations, and three different types of monatomic anions. corresponding to the oxidation states (Ba+2)21(Ge-4)2(O-2) 5(H-)24. The deuterium atoms occupy tetrahedral, square-pyramidal, and octahedral barium interstices while the oxide anions lie in nearly regular octahedral barium polyhedra. The germanide anions are surrounded by 12 barium atoms in a distorted icosahedral configuration. Property measurements show that Ba21Ge2O5H24 is diamagnetic and is a semiconductor (or insulator). The analogues Ba21Tr2O5Hx, Tr = Ga, In, Tl, are isotypic with the heavy-atom structure of the title phase and presumably contain 22 hydride ions.
- Huang, Baoquan,Corbett, John D.
-
-
Read Online
- Excitation laser fluence effects on the Ba ... FCH3 + hv τ BaF + CH3 intracluster reaction
-
In this work, results on the Ba...FCH3 + hv → BaF (Ba*) + CH3 (CH3F) reaction obtained under high laser field conditions are reported. We have found that the two-photodissociation channel yields, i.e. the reactive BaF and non-reactive Ba* products, exhibited opposite behaviour depending upon the laser fluence. Whereas the BaF yield rises as the laser fluence is increased, the Ba* yield decreases over the same laser fluence range. In other words, the product (Ba*)/(BaF) branching ratio changes significantly from low to high laser fluence in such a way that the (photoinitiated) Ba...FCH3 → BaF + CH3 reaction may be controlled by changing the intensity of the excitation laser field.
- González Ure?a,Gasmi,Jiménez,Lobo
-
-
Read Online
- Organic dye compositions and use thereof in photovoltaic cells
-
The present invention provides in one aspect a composition having at least one croconine derivative. This composition may be disposed on a semiconductor layer which is further disposed on an electrically conductive surface to provide a dye-sensitized electrode. The dye-sensitized electrode can be assembled together with a counter electrode and a redox electrolyte to provide a photovoltaic cell. The photovoltaic cell may be used as a single cell or in tandem with other cells.
- -
-
-
- Group 2 metal containing catalyst system
-
The group IIa metal containing catalyst system of this invention can be utilized to synthesize rubbery polymers having a high trans microstructure by solution polymerization. Such rubbery polymers having a high trans microstructure content, such as polybutadiene rubber, styrene-isroprene-butadiene rubber, styrene-butadiene rubber, can be utilized in tire tread rubbers that exhibit improved wear and tear characteristics. This invention more specifically reveals a catalyst system which is comprised of (a) an organolithium compound, including organolithium functionalized compounds, (b) a group IIa metal salt selected from the group consisting of group IIa metal salts of di(alkylene glycol)alkylethers and group IIa metal salts of tri(alkylene glycol) alkylethers, and (c) an organoaluminum compound, and optionally an organomagnesium compound. The subject invention further discloses a process for synthesizing rubbery polymers having a high trans microstructure by a process that comprises polymerizing a conjugated diolefin monomer in an organic solvent in the presence of a catalyst system that is comprised of (a) an organolithium compound, (b) a group IIa metal salt selected from the group consisting of group IIa metal salts of amino glycols and group IIa metal salts of glycol ethers, and (c) an organoaluminum compound.
- -
-
-
- Phenylalkanoic acid esters and their use as antioxidants
-
Compounds of formula (I): STR1 wherein: R1 represents an alkyl group having from 1 to 6 carbon atoms; R2 represents an alkyl group having from 8 to 24 carbon atoms; EO represents an ethyleneoxy group; PO represents a propyleneoxy group; k is 0 or an integer from 1 to 10; and m is an integer from 1 to 4; provided that the total of (k+m) is greater than 1 and not greater than 10; are useful as antioxidant stabilizers for polymeric materials.
- -
-
-
- Novel phosphino derivatives
-
The reaction of compounds of the formula: X2O3P CHY CZ2where Y and each Z are each H, PO3X2, SO3X or CO2X (e.g. vinyl phosphonic acid or vinylidene diphosphonic acid) with hypophosphorous acid in the presence of free radicals provides novel compounds X2O3PCHYCZ2PO2XH which react with monomers such as vinyl sulphonate, vinyl phosphonate, vinylidene diphosphonate and acrylic acid to form telomers useful for scale inhibition, especially barium scale in oil wells. The polymers show better absorption to rock than PVSA and better thermal stability than random copolymers containing equivalent phosphorus.
- -
-
-
- Orthorhombic inverse Perovskitic Ba3TtO (Tt = Ge, Si) as Zintl phases
-
The isotypic title compounds are obtained in high yield from the reactions of Ba, BaO, and Ge (Si) in welded Ta containers slowly cooled from 1100°C. The structure of Ba3GeO was determined by single-crystal X-ray diffraction (orthorhombic symmetry; Pnma (No. 62); a = 7.591(1), b = 10.728(1), c = 7.551(1) A; Z = 4; R = 0.058, Rw = 0.065 for 780 reflections (I > 3σ(I)) with 2θmax = 60°)). The structure consists of slightly deformed OBa6 octahedra that are tilted by ≈ 14° with respect to their positions in the ideal inverse perovskite structure. These distortions optimize eight of the original twelve equal Ba-Ge distances. The ideal cubic Ca3SiO (a = 4.699(1) A) has also been synthesized.
- Huang, Baoquan,Corbett, John D.
-
p. 1787 - 1790
(2008/10/09)
-
- Ba3AlO4H: Synthesis and Structure of a New Hydrogen-Stabilized Phase
-
The title compound and its deuteride were synthesized in high yield by sintering appropriate mixtures of BaH2(BaD2), BaO and Al2O3in welded Ta containers at 1100°C under a hydrogen (deuterium) pressure of 600-700 torr. The structure was determined by a combination of single crystal X-ray and time-of-flight powder neutron diffraction means (orthorhombicPnma,Z=4,a=10.4911(9),b=8.1518(7),c=7.2399(6) A for the deuteride). The compound contains nominal Ba2+cations, AlO5-4complex anions and H-(D-) anions. The hydride is bound in a strongly distorted barium octahedron while the tetrahedral AlO5-4anion is surrounded by eleven barium atoms in a peculiar polyhedral configuration. The HBa6octahedra are linked together by corner-sharing to form a three dimension framework with large voids defined by eight of the HBa6octahedra that are occupied by the tetrahedral AlO5-4anions. The structure is closely related in a hierarchical way to that of orthorhombic inverse perovskitic Ba3GeO.
- Huang, Baoquan,Corbett, John D.
-
p. 570 - 575
(2008/10/08)
-
- Ba3N - A new binary nitride of an alkaline earth metal
-
Reacting Ba and N2 in the stoichiometric ratio 6 : 1 at 670 K, homogenizing the product at 570 K in the presence of Na and subsequently distilling off the Na yields Ba3N. This new subnitride decomposes into Ba2N and Ba at 830 K. Its structure represents a hexagonal rod packing of Ba6/2N chains (anti-TiI3 type, space group P63/mcm; a = 764.18(2) pm, c = 705.01(5) pm; Ba in 6 g with x = 0.2721(2), N in 2 b). The peculiarity of a very spaceous packing of these rods is addressed and discussed as possibly due to a quantum size effect.
- Steinbrenner,Simon
-
p. 228 - 232
(2008/10/09)
-
- Nacreous pigments colored by adsorbed dyes
-
Non-bleeding, non-agglomerated, lustrous colored nacreous pigments are prepared by admixing a laking reagent with an aqueous dispersion of a metal oxide coated substrate nacreous pigment and dyestuff.
- -
-
-
- 2,5-diaryl tetrahydrofurans and analogs thereof as PAF antagonists
-
The present invention is directed to a specifically substituted tetrahydrofuran of the formula (I) STR1 wherein R4 is an alkylthio, alkylsulfinyl or alkylsulfonyl containing group, Y is an alkyl or substituted alkyl group, R6 is an alkyl or a substituted alkyl group and the substituents at positions 3, 4 or 5 are acyclic.
- -
-
-
- Trichloroethanimidic acid esters
-
New and more efficient chemical processes are provided for preparing (αS, 5S)-α-amino-3-chloro-2-isoxazoline-5-acetic acid (AT-125), (αS, 5S)-α-amino-3-bromo-2-isoxazoline-5-acetic acid (bromo AT-125) and the C-5 epimers thereof. The disclosed processes allow the above-mentioned antitumor agents to be produced in high yield and purity with substantially fewer steps than prior art chemical procedures.
- -
-
-
- Sulfonated monoazo colorant lake obtained by di-azo coupling of 5-acetylamino-2-aminobenzene-1-sulfonic acid with 1-(3'-sulfophenyl)-3-methylphyrazol-5-one
-
This invention relates to a method of dyeing thermoplastics with sulfonated monoazo colorant lakes having a sulfophenyl pyrazole substituent, of general formula STR1 wherein R is CH3 or COO- ; X is Cl, CH3, CH3 O, C2 H5 O, C2 H5 CONH, NH2 CONH, C6 H5 CONH, CH3 SO2 NH, C6 H5 SO2 NH, CH3 CONH, or hydrogen; Y is hydrogen, Cl, or CH3 ; Z is hydrogen or Cl, n is 0, 1 or 2; and Me+ is one equivalent of a cation selected from the group consisting of NH4+, Li+, K+, Na+, 1/2Sr2+, 1/2Mn2+, 1/2Ni2+, 1/2Ba2+, 1/2Mg2+ and 1/2Ca2+ ; with the proviso that if R is COO-, the additional equivalent charge is compensated by a further equivalent of said or another cation. These compounds, which are insoluble in organic solvents and sparingly soluble in water, are useful as lakes with good pigmentary characteristics and possessing very good lightfastness in plastics, such as polyolefins, polyvinyl chloride, polystyrene, and ABS. They are also useful in surface coatings, and particularly suitable for coloring thermoplastics. Noteworthy is their good plasticizer fastness, their high stability to heat and the absence of blooming they produce when used.
- -
-
-
- Kinetics of the Carbothermal Reduction of Subgroup IIA Oxides
-
The reduction by carbon of solid oxides of type-analogue elements of subgroup IIA involves CO as a reducing agent, with formation of vapour of the reduced metal and CO2.The carbon regenerates the CO and forms carbides of the metals.For the oxides CaO, SrO, BaO (of shell-analogue elements) we have established a general correlation between the rate of the reaction and the Gibbs free energy of the reduction by carbon to the vapour of the metal.
- Vodop'yanov, A. G.
-
p. 1621 - 1624
(2007/10/02)
-
- Novel taurine derivatives
-
Novel taurine derivatives of general formula (I) STR1 (wherein R1 is nicotinoyl, 3,4,5-trimethoxybenzoyl or acetylsalicyloyl and R2 is as defined for R1 or is --CH2 CH2 OR1) have antilipemic and choleretic activities. The compound in which R2 =--CH2 CH2 OR1 and R1 is acetylsalicyloyl exhibits high antiinflammatory, analgesic and antipyretic activity and is essentially free of the unfavorable effect of acetylsalicylic acid on the stomach.
- -
-
-
- Pyrazole compounds as stabilizers for organic materials
-
The present invention concerns certain novel compounds falling under the general formula: STR1 WHEREIN R1, R2 and R3 are substituents, e.g. alkyl and Me is hydrogen or a metal cation. The compounds are useful stabilizers of organic material against the degradative effect of heat, oxidation and U.V. light.
- -
-
-
- 3,3'-Di(sulfonyloxy-group-containing)substituted benzidine derivatives
-
Disclosed are benzidine derivatives substituted in each of the 3,3'-positions by the substituent STR1 wherein W is hydrogen or an alkali metal, the subscript n is zero when A is the divalent branched chain alkylene having from 2 to about 7 carbon atoms, and n is one when A is straight chain divalent alkylene with 3 or 4 carbons. Also disclosed are the corresponding derivatives wherein the sulfonyl group is replaced by the carbonyl group. Further disclosed are chromogen-reactive indicator compositions having as their chromogen constituent one of the foregoing benzidine derivatives. These compositions (1) are useful to test for a substance for which there exists a specific oxygen-oxidoreductase, such as a sugar, an amino acid, uric acid, and the like, and thus (2) contain also a peroxidase, a hydrogen-peroxide-oxidoreductase, and a specific oxygen-oxidoreductase for the specific material in the testing of which the composition is to be used.
- -
-
-
- Separation of wool fatty acid
-
Wool fatty acid is effectively separated from wool alcohol or wool wax by treating a mixture of a multivalent metal soap of the fatty acid and the alcohol or wax with a heterogeneous system comprising a water phase and a water-immiscible solvent phase, and allowing the system to separate into respective phases.
- -
-
-