Neuartige Mäander mit Co3+ und Au3+: Na4[AuCoO5] = Na8 [(O2/2(CoO)O2AuO2/2)2]

Novel meander with Co³⁺ und Au³⁺: Na₄[AuCoO₅] = Na₈ ¹∞ [(O_2/2 (CoO)O₂AuO_2/2)₂] By “reaction with the wall” we obtained for the first time transparent brown single crystals of Na₄[AuCoO₅] while heating intimate mixtures of Co₃O₄, Na₂O₂, and K₂O₂ (Co: Na: K = 1.00:4.91:2.20; 650°C/44d) in a sealed gold-tube: monoclinic, P2₁/m, with a = 555.69(4) pm, b = 1042.11 (8) pm, c = 555.69(4) pm, β = 117.387(5)°, Z = 2. Characteristic features of Na₄[AuCoO₅] are meandric chains [(O_2/2 (CoO)O₂AuO_2/2)₂]. The structure has been determined by four-circle diffractometer data (Siemens AED 2; Mo? Kα , graphite, 881 I₀(hkl), R = 0.0366, R_w = 0.0316), parameters as given in the text. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, these via Mean Fictive Ionic Radii, and Charge-distribution, CHARDI, are calculated and discussed.     

Solutions of alkali soaps and water in fatty acids IX. The location of theL 2-phase in three-component systems of sodium soap — fatty acid — water,in view of the occurrence of acid soaps

Previous studies of the occurrence of acid soaps in systems containing a longchain sodium soap and the corresponding fatty acid, and the study of phase equilibria in the system sodium octanoate — octanoic acid — water, performed by our group at the beginning of the 1960s, show that the isotropic liquidL ₂-phase of the last mentioned system in its whole region of existence is situated in that part in which acid soaps occur. This provides an explanation for the fact that theL ₂-phase itself contains acid sodium octanoates in all regions. TheL ₂-phase has its origin in the water-free melt of fatty acid and neutral soap in which these components react with each other under the formation of an acid soap. When water is added to the system, this water-free acid soap is transformed into different hydrated acid soaps. In a large region of concentration, there is an extremely close relation between theL ₂-phase and the liquid-crystalline lamellarD-phase, which itself consists of hydrated acid soaps. At its outermost water-rich tip, theL ₂-phase is in equilibrium with theL ₁-phase of the system, just above the+LAC, that is, with the most dilute aqueous soap solution in which acid soap still may be formed in aqueous environment. Formation of acid soap is a fundamental requirement for the existence of this isotropic liquidL ₂-phase.     

The influence of activated carbon on the thermal decomposition of sodium ethyl xanthate

The thermal decomposition of SEX in a nitrogen atmosphere was studied by coupled thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR), and by pyrolysis-gas chromatography-mass spectrometry (py-GC-MS). The TG curve exhibited two discrete mass losses of 45.8% and 17.8% respectively, at 200 and 257–364°C. The evolved gases identified as a result of the first mass loss were carbonyl sulfide (COS), ethanol (C₂H₅OH), ethanethiol (C₂H₅SH), carbon disulfide (CS₂), diethyl sulfide ((C₂H₅)₂S), diethyl carbonate ((C₂H₅O)₂CO), diethyl disulfide ((C₂H₅)₂S₂), and carbonothioic acid, O, S, diethyl ester ((C₂H₅S)(C₂H₅O)CO). The gases identified as a result of the second mass loss were carbonyl sulfide, ethanethiol, and carbon disulfide. Hydrogen sulfide was detected in both mass losses by py-GC-MS, but not detected by FTIR. The solid residue was sodium hydrogen sulfide (NaSH).SEX was adsorbed onto activated carbon, and heated in nitrogen. Two discrete mass losses were still observed, but in the temperature ranges 100–186°C (7.8%) and 186–279°C (11.8%). Carbonyl sulfide and carbon disulfide were now the dominant gases evolved in each of the mass losses, and the other gaseous products were relatively minor. It was demonstrated that water adsorbed on the carbon hydrolysed the xanthate to cause the first mass loss, and any unhydrolysed material decomposed to give the second mass loss.Mr. N. G. Fisher would like to thank the A. J. Parker CRC for Hydrometallurgy for the provision of a PhD scholarship.     

聚对苯乙烯磺酸钠添加剂的分子量对水煤浆浆体性质的影响

选用了变质程度不同的八种煤和三种不同分子量的聚对苯乙烯磺酸钠（PSS）添加剂，详细考查了该添加剂的分子量对水煤浆浆体性质的影响。结果发现，在考查PSS相对分子量的范围内（质均分子量为5.34×104～33.39×104），八种煤的水煤浆成浆性随着分子量的增大而增加，水煤浆成浆性与PSS添加剂的平均分子量的关系可归因于添加剂在煤粒上的吸附，分子量小的PSS在煤粒上的吸附量大于分子量大的PSS；PSS分子量的增加有利于水煤浆的流变性由胀性向假塑性转变；PSS分子量的增加使水煤浆的静态稳定性得到显著的改善。     

Synthesis, Crystal and Magnetic Structures of the Sodium Ferrate (IV) Na4FeO4 Studied by Neutron Diffraction and Mössbauer Techniques

The alkali sodium ferrate (IV) Na₄FeO₄ has been prepared by solid-state reaction of sodium peroxide Na₂O₂ and wustite Fe_1−xO, in a molar ratio Na/Fe=4, at 400°C under vacuum. Powder X-ray and neutron diffraction studies indicate that Na₄FeO₄ crystallizes in the triclinic system P−1 with the cell parameters= a=8.4810(2) Å, b=5.7688(1) Å, c=6.5622(1) Å, α=124.662(2)°, β=98.848(2)°, γ=101.761(2)° and Z=2. Na₄FeO₄ is isotypic with the other known phases Na₄MO₄ (M=Ti, Cr, Mn, Co and Ge, Sn, Pb). The solid solution Na₄Fe_xCo_1−xO₄ exists for x=0-1 and we have followed the evolution of the cell parameters with x to determine the lattice parameters of the triclinic cell of Na₄FeO₄. A three-dimensional network of isolated FeO₄ tetrahedra connected by Na atoms characterizes the structure. This compound is antiferromagnetic below T_N=16 K. At 2 K the magnetic cell is twice the nuclear cell and the magnetic structure is collinear (μ_Fe=3.36(12) μ_B at 2 K). This black compound is highly hygroscopic. In water or on contact with the atmospheric moisture it is disproportionated in Fe³⁺ and Fe⁶⁺. The Mössbauer spectra of Na₄FeO₄ are fitted with one doublet (δ=− 0.22 mm/s, Δ=0.41 mm/s at 295 K) in the paramagnetic state and with a sextet at 8K. These parameters characterize Fe⁴⁺ high-spin in tetrahedral FeO₄ coordination.     

An Efficient Route to Prepare Metal Organosols by Phase Transfer Procedure

Silver and gold organosols are easily prepared by transferring nanoparticles from aqueous phase into isooctane with high efficiency (＞90%). Concentrations of sodium oleate and magnesium chloride have crucial effects on the transfer efficiency. Based on the UV-visible absorption spectra, TEM micrographs of nanoparticles, as well as molecular modeling calculation about the adsorption conformation of sodium oleate molecules, a possible phase transfer mechanism is proposed.     

Synthesis and X-ray structural analysis of a unique Co-crystallization complex of [NaSal]2DB24C8 and [KSal]2DB24C8

Sodium salicylate (NaSal where Sal=2-hydroxybenzoate), when mixed with dibenzo-24-crown-8 (DB24C8) yields a bimetallic complex [NaSal]₂DB24C8 in most polar organic media, while potassium salicylate (KSal) under similar conditions shows a tendency to yield 11 or 21 complexes depending upon medium or synthesis. However, the presence of both NaSal and KSal together results in a unique mixed cation complex of composition NaKSal₂DB24C8. This product melts sharply (190-92°C) without decomposition, displays IR spectral characteristics comparable to those of [Na(Sal)]₂DB24C8, and is stable in aqueous media as shown by the detectable cation effect on the UV absorption bands of Sal and DB24C8. Single crystal X-ray analysis of NaK(Sal)₂DB24C8 reveals that the system represents a co-crystallization complex of individual (KSal)₂DB24C8 and (NaSal)₂DB24C8 molecules. The crystals are monoclinic,P2₁/c,a=19.976(2) Å,b=9.031(1) Å,c=25.541(5) Å,=122.065(9)°, ų,T=298 K,Z=2+2, CuK =1.5418 Å, and 2 (2.5°–100°). FinalR factor for the 3012 observed reflections (F>3) is 0.092. Both the Na₂- and K₂-molecules possess crystallographic centers of symmetry with one metal and its associated anion on each side of the crown ring. However, the conformations of the crowns are very different in the two molecules, with the K₂-crown being nearly planar and the Na₂-crown being quite puckered. Four oxygen atoms from the DB24C8 (KO, 2.680–2.908 Å) and three carboxyl oxygen atoms (KO, 2.472–2.708 Å) from separate salicylate ions coordinate with each potassium. Three oxygens from the crown (NaO, 2.536–2.65 Å) and three carboxyl oxygens (NaO, 2.31–2.563 Å) coordinate with each sodium. The salicylate ions lie on opposite sides and nearly perpendicular (77.2°, Na₂-molecule; 82.7° K₂-molecule) to each crown but coordinate to both of the metal ions within a molecule. The K⁺K⁺ and Na⁺Na⁺ distances in the respective molecules are 3.95 and 3.34 Å. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82044 (18 pages).     

Structural difference between a superconducting sodium cobalt oxide and its related phase

Monolayer hydrate (MLH) Na_xCoO₂·y′H₂O was obtained from superconducting bilayer hydrate (BLH) Na_xCoO₂·yH₂O by partial extraction of H₂O molecules between the CoO₂ layers. Magnetization measurements indicated that electron densities in the CoO₂ layer of the MLH phase remained unchanged after the water extraction. Nevertheless, superconductivity was completely suppressed in the MLH phase. This strongly suggests that the highly 2D nature in the BLH phase due to its thick insulating layers consisting of H₂O molecules and Na⁺ ions plays an important role for inducing superconductivity.     

Ethanol Washing Effect on Textural Properties of the Sodium Silicate-Derived Silica Xerogel

This study deals with the use of ethanol as washing solvent in the preparation of the silica gels from sodium silicate in order to enhance the textural properties, especially surface area. We here examined the effect of ethanol-washing on surface area, micro- and mesopore volume, and average pore size. The silica xerogels prepared from sodium silicate solution exhibited an extremely high surface area of 1139 m2/g by washing their hydrogels with ethanol. Compared to water-washed xerogels, ethanol-washed xerogels showed higher surface areas, total pore volumes, and larger average pore sizes. Unlike the surface area of water-washed xerogel, that of the ethanol-washed xerogel was not affected by the silica concentration of initial solution. This study indicates that the textural properties of sodium silicate-derived xerogels are further enhanced by using ethanol as washing solvent.     

The Additive Influence of Propane-1,2-Diol on SDS Micellar Structure and Properties

Micellar systems are colloids with significant properties for pharmaceutical and food applications. They can be used to formulate thermodynamically stable mixtures to solubilize hydrophobic food-related substances. Furthermore, micellar formation is a complex process in which a variety of intermolecular interactions determine the course of formation and most important are the hydrophobic and hydrophilic interactions between surfactant–solvent and solvent–solvent. Glycols are organic compounds that belong to the group of alcohols. Among them, propane-1,2-diol (PG) is a substance commonly used as a food additive or ingredient in many cosmetic and hygiene products. The nature of the additive influences the micellar structure and properties of sodium dodecyl sulfate (SDS). When increasing the mass fraction of propane-1,2-diol in binary mixtures, the c.m.c. values decrease because propane-1,2-diol is a polar solvent, which gives it the ability to form hydrogen bonds, decreasing the cohesivity of water and reducing the dielectric constant of the aqueous phase. The values of ΔGm0 are negative in all mixed solvents according to the reduction in solvophobic interactions and increase in electrostatic interaction. With the rising concentration of cosolvent, the equilibrium between cosolvent in bulk solution and in the formed micelles is on the side of micelles, leading to the formation of micelles at a lower concentration with a small change in micellar size. According to the ¹H NMR, with the addition of propylene glycol, there is a slight shift of SDS peaks towards lower ppm regions in comparison to the D₂O peak. The shift is more evident with the increase in the amount of added propane-1,2-diol in comparison to the NMR spectra of pure SDS. Addition of propane-1,2-diol causes the upfield shift of the protons associated with hydrophilic groups, causing the shielding effect. This signifies that the alcohol is linked with the polar head groups of SDS due to its proximity to the SDS molecules.