Natalia V. Kotova

Enthalpies of mixing in liquid alloys of iron with the lanthanides

Abstract The enthalpies of mixing in binary liquid alloys of iron with the lanthanides (Pr, Nd, Gd, Tb, Dy and Lu) were determined at 1550–1950 K by means of isoperibolic calorimetry. They show exothermic effects (in the Fe–Pr system partially endothermic) which increase across the lanthanides row from the Fe–Pr system (ΔHmin = −0.35 ± 0.10 kJ · mol−1 at xPr = 0.22; ΔHmax = 0.75 ± 0.24 kJ · mol−1 at xPr = 0.76; T = 1829 K) to the Fe–Lu system (ΔHmin = −11.58 ± 0.50 kJ · mol−1 at xLu = 0.35; T = 1950 K).

Mixing enthalpies in binary Ce-Sb and ternary Ce-Co-Sb liquid alloys

Abstract The enthalpies of mixing in liquid alloys in the binary Ce-Sb and ternary Ce-Co-Sb systems were determined over a wide range of composition by means of isoperibolic calorimetry in the temperature range 1 600-1 723 K. The minimum value of the integral enthalpy of mixing (ΔHmin) in the Ce-Sb system was evaluated to be −123 kJ mol-1 at xCe = 0.55. The enthalpies of mixing in liquid ternary alloys were found to increase smoothly from the binary boundary systems Co-Ce and Co-Sb towards the Ce-Sb system reaching the value of approximately −123 kJ mol-1 in the vicinity of the phase CeSb.

Bis-{(E)-3-[2-(hy-droxy-imino)-propan-amido]-2,2-dimethyl-propan-1-aminium} bis[μ-(E)-N-(3-amino-2,2-dimethyl-prop-yl)-2-(hy-droxy-imino)-propanamido-(2-)]bis-{[(E)-N-(3-amino-2,2-dimethyl-prop-yl)-2-(hy-droxy-imino)-propanamide]-copper(II)} bis-((E)-{3-[2-(hy-droxy-imino)-propanamido]-2,2-dimethyl-prop-yl}carbamate) acetonitrile disolvate.

The reaction between copper(II) nitrate and (E)-N-(3-amino-2,2-dimethylpropyl)-2-(hydroxyimino)propanamide led to the formation of the dinuclear centrosymmetric copper(II) title complex, (C8H18N3O2)2[Cu2(C8H15N3O2)2(C8H17N3O2)2](C9H16N3O4)2·2CH3CN, in which an inversion center is located at the midpoint of the Cu2 unit in the center of the neutral [Cu2(C8H15N3O2)2(C8H17N3O2)2] complex fragment. The Cu2+ ions are connected by two N—O bridging groups [Cu⋯Cu separation = 4.0608 (5) Å] while the CuII ions are five-coordinated in a square-pyramidal N4O coordination environment. The complex molecule co-crystallizes with two molecules of acetonitrile, two molecules of the protonated ligand (E)-3-[2-(hydroxyimino)propanamido]-2,2-dimethylpropan-1-aminium and two negatively charged (E)-{3-[2-(hydroxyimino)propanamido]-2,2-dimethylpropyl}carbamate anions, which were probably formed as a result of condensation between (E)-N-(3-amino-2,2-dimethylpropyl)-2-(hydroxyimino)propanamide and hydrogencarbonate anions. In the crystal, the complex fragment [Cu2(C8H15N3O2)2(C8H17N3O2)2] and the ion pair C8H18N3O2 +.C9H16N3O4 − are connected via an extended system of hydrogen bonds.

Enthalpies of mixing in binary Mn–In and ternary Mn–In–Gd liquid alloys

Abstract The enthalpies of mixing in liquid alloys of the binary Mn–In and ternary Mn–In–Gd systems were determined over a wide range of compositions by means of isoperibolic calorimetry in the temperature range 1 500 – 1 650 K. The enthalpies of mixing in the Mn–In system demonstrate endothermic effects (ΔHmax = 4.66 ± 0.38 kJ · mol−1 at xIn = 0.40). The enthalpies of mixing in the liquid ternary Mn–In–Gd alloys were determined along six sections (xMn/xIn = 0.22/0.78; 0.44/0.56; 0.65/0.35 and 0.83/0.17 for xGd changed from 0 up to 0.5 and xMn/xGd = 0.30/0.70; 0.60/0.40 for xIn changed from 0 up to 0.3). Enthalpies of mixing in the ternary system were found to be predominantly exothermic and steadily increasing in absolute values towards the Gd–In boundary binary system, reaching the maximum value in the vicinity of the phase GdIn.

Enthalpies of mixing in binary liquid alloys of lutetium with 3d metals

Abstract The enthalpies of mixing in binary liquid alloys of lutetium with chromium, cobalt, nickel and copper were determined at 1 773 – 1 947 K by isoperibolic calorimetry. The enthalpies of mixing in the Lu–Cr melts (measured up to 40 at.% Cr) demonstrate endothermic effects (ΔH = 6.88 ± 0.66 kJ · mol−1 at xLu = 0.60), whereas significant exothermic enthalpies of mixing have been established within a wide composition region for the Co–Lu, Ni–Lu and Cu–Lu liquid alloys. Minimum values of the integral enthalpy of mixing are as follows: ΔHmin = −23.57 ± 1.41 kJ · mol−1 at xLu = 0.38 for the Co–Lu system; ΔHmin = −48.65 ± 2.83 kJ · mol−1 at xLu = 0.40 for the Ni–Lu system; ΔHmin = −24.63 ± 1.52 kJ · mol−1 at xLu = 0.37 for the Cu–Lu system.

Enthalpies of mixing in binary Fe–Sb, Ce–Fe and ternary Ce–Fe–Sb liquid alloys

Abstract The enthalpies of mixing in liquid alloys in the binary Fe–Sb, Ce–Fe and ternary Ce–Fe–Sb systems were determined over a wide range of composition by means of isoperibolic calorimetry in the temperature range 1600–1830 K. The minimum values of the integral enthalpy of mixing (ΔHmin) were determined to be (−2.32 ± 0.22) kJ · mol−1 at xSb = 0.5 in the Fe–Sb system, and (−0.97 ± 0.19) kJ · mol−1 at xCe = 0.35 in the Ce–Fe system. The enthalpies of mixing in liquid ternary Ce–Fe–Sb alloys were found to increase smoothly from the binary boundary systems Ce–Fe and Fe–Sb towards the Ce–Sb system, reaching the minimum value of (−107.5 ± 3.6) kJ · mol−1 in the vicinity of the phase CeSb.

Poly[μ-aqua-diaquabis­[μ-2-cyano-2-(oxidoimino)­acetato]­copper(II)dipotassium]

In the title compound, [CuK2(C3N2O3)2(H2O)3]n, the Cu2+ atom is in a distorted square-pyramidal coordination geometry. Two N atoms belonging to the oxime groups and two O atoms belonging to the carboxylate groups of two trans-disposed doubly deprotonated residues of 2-cyano-2-(hydroxyimino)acetic acid make up the basal plane and the apical position is occupied by the water molecule. The neighboring Cu-containing moieties are linked into a three-dimensional framework by K—O and K—N contacts formed by two potassium cations with the carboxylate and the oxime O atoms and the nitrile N atoms of the ligand. The environments of the K+ cations are complemented to octa- and nonacoordinated, by K—O contacts with H2O molecules. The crystal structure features O—H⋯O hydrogen bonds.

Tris(2,2′-bipyridine-κ2N,N′)cobalt(III) bis­[bis­(pyridine-2,6-dicarboxyl­ato-κ3O2,N,O6)cobaltate(III)] perchlorate dimethyl­formamide hemisolvate 1.3-hydrate

In the title compound, [Co(C10H8N2)3][Co(C7H3NO4)2]2(ClO4)·0.5C3H7NO·1.3H2O, the CoIII atom in the complex cation is pseudooctahedrally coordinated by six N atoms of three chelating bipyridine ligands. The CoIII atom in the complex anion is coordinated by two pyridine N atoms and four carboxylate O atoms of two doubly deprotonated pyridine-2,6-dicarboxylate ligands in a distorted octahedral geometry. One dimethylformamide solvent molecule and two water molecules are half-occupied and one water molecule is 0.3-occupied. O—H⋯O hydrogen bonds link the water molecules, the perchlorate anions and the complex anions. π–π interactions between the pyridine rings of the complex anions are also observed [centroid–centroid distance = 3.804 (3) Å].

fac-Tris(pyridine-2-carboxyl-ato-κN,O)cobalt(III).

In the title compound, [Co(C6H4NO2)3], the CoIII ion lies on a threefold rotation axis and is in a distorted octahedral environment defined by three N and three O donor atoms from three fac-disposed pyridine-2-carboxylate ligands. The ligands are coordinated in a chelate fashion, forming three five-membered rings. In the crystal, translationally related complex molecules are organized into columns along [001] via C—H⋯O hydrogen bonds.

Dibromidobis(3,5-dimethyl-1H-pyrazole-κN)cobalt(II).

In the mononuclear title complex, [CoBr2(C5H8N2)2], the CoII atom is coordinated by two N atoms from two monodentate 3,5-dimethylpyrazole ligands and two Br atoms in a highly distorted tetrahedral geometry. In the crystal, the complex molecules are linked by intermolecular N—H⋯Br hydrogen bonds into chains along [101]. An intramolecular N—H⋯Br hydrogen bond is also present.