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The phase equilibrium diagram of the CaO-½Ho2O3-CoOz system was determined at 885 °C in air. This diagram offers compatibility relationships in the ternary oxide system that are essential for processing and for the understanding of properties of several thermoelectric phases in the system. Four three-phase regions and three solid solution tie-line regions were determined in the CaO-½Ho2O3-CoOz system. In the CaO-Ho2O3 system, while a small solid solution region was identified for (Ho1-xCax)O(3-z)/2 (0 ≤x ≤ 0.14), Ho was not present in the Ca site of CaO. Neither the reported Ho2CoO4 phase in the Ho2O-CoOz system nor the Ca-doped (Ho1+xCa1-x)CoO4-z phase was present at 885 °C. No solid solution of the distorted perovskite, (Ho1-xCax)CoO3-z, was established at this temperature. The CaO-CoOz system consists of two calcium cobaltate thermoelectric compounds. The 2D thermoelectric oxide, (Ca3-xHox)Co4O9-z (0 ≤x ≤ 0.5), has a misfit layered structure, and the 1D Ca3Co2O6 consists of chains of alternating CoO6 trigonal prisms and CoO6 octahedra. Ca3Co2O6 was found to be a stoichiometric compound. A comparison of the phase diagrams of the CaO-½R2O3-CoOz (R = La, Nd, Eu, and Ho) systems is given.

Synchrotron X-ray single crystal structure determination of two 2D Hofmann-related compounds, [Ni(p-Xylyenediamine)n-tetracyanonickelate] (abbreviated as Ni-pXdam) and [Ni(tetrafluoro-p-Xylyenediamine)n-tetracyanonickelate] (abbreviated as Ni-pXdamF4), have been conducted. Both the pXdam and pXdamF4 ligands contain two short chains of -CH2NH2 at the para-positions of a phenyl ring. These flexible chains link the 6-fold coordinated Ni2 sites throughout the network. In Ni-pXdam, the closed-2D network of [Ni-(CN-Ni1/4-)4]∞ is broken into 1D chains, leaving the C≡N groups at the trans-positions of the Ni(CN)4 moiety unbridged. The resulting 1D chains [(trans-)-NC-Ni(CN)2-CN-Ni-]∞ runs along the [010] direction of the unit cell. The pXdam ligands bridge in pair between the Ni atoms of the adjacent chains. The catenation structure of [Ni{(pXdam)}]∞ could be referred to as double -1D. In Ni-pXdamF4, the -CH2NH2 ligands connect the neighboring chains via the 6-fold Ni2 site. Surrounding the 4-fold Ni1 site, the two trans terminal C≡N groups were replaced by the Lewis base NH3 during the synthesis process, therefore preventing the propagation of the 2D net to form a 3D network. Computed pore volume of both compounds indicated that there is not sufficient space in the structure to accommodate gas molecules. In both compounds, hydrogen bonds were found, and solvent of crystallization was absent due to the limited free space in the structure.

The flexible metal organic framework (MOF) compound, Ni(L)[Ni(CN)4], (L = 4,4′azopyridine (C10N4H8), nicknamed AzoPyr) is a 3D porous material that adopts the Hofmann-type structure. This paper reports our synthesis of Ni-AzoPyr and its structural, bonding, and sorption characterization. The red monoclinic crystals (with space group P2/n) were found to be multiple twins with three main components related by twin laws. The lattice parameters are a = 7.102 (3) A, b = 14.154 (4) A, c = 25.655 (10) A, β = 92.575 (12)°, and V = 2577 (2) A3. Ni-AzoPyr adopts a pillared structure with layers defined by the 2-D Ni [Ni(CN)4]n nets and AzoPyr ligands as pillars linking between 6-fold coordinated Ni3 sites. An additional AzoPyr ligand was found to cross link between the 6-fold Ni1 sites to the open ends of the four-fold Ni2 sites. This arrangement results in a 5-fold pseudo square-pyramid for Ni2 and a significantly long Ni2–N distance of 2.436 (11) A. Density functional theory (DFT) calculations show that almost all states in the conduction band minimum (CBM) are occupied by the 6-fold coordinated Ni site, indicating little to no electrons are conducted at the 5-fold coordinated Ni site. Water molecules were found to be entrapped in the cavities of the structure. In addition to the gating adsorption feature of Ni-AzoPyr, using computational approach, we found that in the absence of water molecules, the pores were found to have a local diameter of 5.8 A with a maximum number of 15.5 CO2 molecules per unit cell. The inclusion of disordered water solvent molecules gives rise to the formula of Ni(AzoPyr)[Ni(CN)4]·0.8H2O, or C19H12N10Ni2·0.8(H2O).

The crystal structures, solid solution limit, and powder X-ray reference diffraction patterns for two ‘natural superlattice’ series Bi1-xBaxCuOSe (x = 0.05, 0.075, 0.1, 0.2, and 0.3), and Bi1-xCaxCuOSe (x = 0, 0.05, 0.075, 0.1, 0.2 and 0.3) have been determined. The structure/property relationships of these thermoelectric materials are summarized. As the ionic radius of Ba2+ is greater than that of Bi3+, the unit cell volume, V, of Bi1-xBaxCuOSe increases progressively from x = 0 to x = 0.2 (from 137.868 (5) A3 to 141.194 (10) A3, respectively). However, even though the ionic radius of Ca2+ is smaller than that of Bi3+, the unit cell volumes, V, of Bi1-xCaxCuOSe also show an increasing trend as a function of x (137.868 (5) A3 to 139.295 (12) A3 from x = 0 to 0.3, respectively) due to the relatively large increase in c parameter. The structure of Bi1-xAxCuOSe (A = Ba and Ca) can be considered as built from [Bi2(1-x)A2xO2]2(1−x)+ layers normal to the c-axis alternating with fluorite-like [Cu2Se2]2(1−x)- layers in the c-direction. The substitutions of Ba and Ca on the Bi site of Bi1-xAxCuOSe lead to the weakening of the ‘bonding’ between the [Bi2(1-x)A2xO2]2(1−x)+ and the [Cu2Se2]2(1−x)- layers (a decrease of Columbic force), resulting in an increase of the c-axis parameter and V. Powder X-ray diffraction patterns of Bi1-xAxCuOSe were submitted for inclusion in the Powder Diffraction File (PDF).

Crystal structures and X-ray reference powder diffraction patterns have been determined for the Ba12Nb8-xTaxCo4O36 (x = 1, 3, 4, 5, 7) series. Ba12Nb8-xTaxCo4O36 crystallize in the cubic perovskite structure with a space group Pm 3 ¯ m (No. 221) and the lattice parameter increasing from a = 4.08732(3) A to a = 4.08894 (2) A as x varies from 1 to 7. The Goldschmidt distortion parameter for the entire series is about 1.05 (1.0488–1.0506), being similar to that of the cubic end member Ba3Nb2CoO9. Transmission electron microscopy of the composition Ba12Nb4Ta4Co4O36 (or Ba3(NbTaCo)O9) revealed nanoscale 1:2 ordering of Nb/Ta and Co, manifested in the presence of the diffuse superlattice reflections. As this ordering is limited to short range, the average structures were still refined assuming the ideal-perovskite cubic symmetry. X-ray powder diffraction patterns of the studied compounds have been submitted to the Powder Diffraction File (PDF).

A combinatorial film of the LaCo1-xCrxO3 system was fabricated using the LaCoO3 and LaCrO3 targets at the NIST Pulsed Laser Deposition (PLD) facility. As the ionic size of Cr3+ is greater than that of Co3+, the unit cell volume of the series increases with increasing x. Using a custom screening tool, the Seebeck coefficient of LaCo1-xCrxO3 approaches a measured maximum of 286 μV/K, near to the cobalt-rich end of the film library (with x ≈ 0.49). The resistivity value increases continuously with increasing x. The measured power factor, PF, of this series, which is related to the efficiency of energy conversion, also exhibits a maximum at the composition of x ≈ 0.49, which corresponds to the maximum value of the Seebeck coefficient. Our results illustrate the efficiency of applying the high-throughput combinatorial technique to study thermoelectric materials.

The CaO-½Eu 2 O 3 -CoO z system prepared at 885 °C in air consists of two calcium cobaltate compounds, namely, the 2D thermoelectric oxide solid solution, (Ca 3−x Eu x )Co 4 O 9−z (0 ≤ x ≤ 0.5) which has a misfit layered structure, and the 1D Ca 3 Co 2 O 6 compound which consists of chains of alternating CoO 6 trigonal prisms and CoO 6 octahedra. Ca 3 Co 2 O 6 was found to be a point compound without the substitution of Eu on the Ca site when prepared at 885 °C. A solid solution region of distorted perovskite, (Eu 1−x Ca x )CoO 3−z (0 ≤ x ≤ 0.22, space group Pnma ) was established. The (Eu 0.91(1) Ca 0.09(1) )CoO 3−z perovskite member has a distorted structure with tilt angles θ (17.37°), ϕ (8.20°), and ω (19.16°) which represent rotations of an octahedron about the pseudo-cubic perovskite [110] p , [001] p and [111] p axes. The reported Eu 2 CoO 4 phase was not observed at 885 °C, but a ternary Ca-doped oxide, (Eu 1+x Ca 1−x )CoO 4−z ( Bmab ) where 0 ≤ x ≤ 0.10 was found to be stable at this temperature. In the peripheral binary systems, Eu was not present in the Ca site of CaO, while a small solid solution region was identified for (Eu 1−x Ca x )O (3−z)/2 (0 ≤ x ≤ 0.05). Seven solid solution tie-line regions and six three-phase regions were determined in the CaO-½Eu 2 O 3 -CoO z system in air.

X-ray data of a powder sample of α-chlorohemin (a member of the porphyrin family), C34H32ClFeN4O4, was collected using synchrotron radiation at the Advanced Photon Source (APS, Argonne National Laboratory). Rietveld Refinement and Density Functional Theory (DFT) calculations were performed for obtaining the structure including positions of hydrogen atoms. The structure was found to be P 1 ¯ , Z = 2; at 100K the lattice parameters are a = 11.22468(6) A, b = 13.93930(8) A, c = 10.79818(9) A, α = 99.6672(6)°, β = 108.4124(8)°, γ = 106.7175(6)°, and V = 1471.713(19) A3, and at 295K, a = 11.43217(7) A, b = 14.06412(10) A, c = 10.85390(9) A, α = 98.6655(7)°, β = 108.6294(8)°, γ = 107.5025(7)°, and V = 1517.21(2) A3, Dx = 1.427 g/cm3. Experimental reference X-ray patterns have also been determined, which will be included in the Powder Diffraction File (PDF).

The chartreuse monoclinic Ni-dpbz (Ni(L)[Ni(CN) 4 ], (L = 1,4-Bis(4-pyridyl)benzene, or dpbz) crystal assumes a pillared structure with layers defined by 2-D Ni[Ni(CN) 4 ] n nets and dpbz ligands as pillars, linking between coordinated Ni sites. In addition to the hysteretic adsorption/desorption feature of Ni-dpbz, in half of the parallelepiped-shape space enclosed by the pillars and nets, an additional dpbz ligand was found to link between the open ends of two four-fold Ni sites. This arrangement results in an unusual 5-fold pseudo square-pyramid environment for Ni and a significantly long Ni–N distance of 2.369(4) A. The presence of disordered dimethyl sulfoxide (DMSO) solvent molecules give rise to the formula of Ni(dpbz)[Ni(CN) 4 ]·½dpbz·0.44DMSO. Sorption isotherms showed flexible behavior during the adsorption and desorption of CO 2 .

The CaO-½Gd2O3-CoOz system prepared at 885 °C in air consists of two thermoelectric calcium cobaltate compounds, namely, the 2D thermoelectric oxide solid solution, (Ca3-xGdx)Co4O9-z (0 ≤ x ≤ 0.42) which has a misfit layered structure, and the 1D Ca3Co2O6 compound which consists of chains of alternating CoO6 trigonal prisms and CoO6 octahedra. Ca3Co2O6 was found to be a point compound. In the peripheral binary systems, Gd was not present in the Ca site of CaO, while a small solid solution region was identified for (Gd1-xCax)O(3-z)/2 (0 ≤ x ≤ 0.075). A solid solution region of distorted perovskite, (Gd1-xCax)CoO3-z (0 ≤ x ≤ 0.24, space group Pnma) was established. The structure of a member of the solid solution, (Gd0.92Ca0.08)CoO3-z, was determined using high resolution synchrotron radiation. A ternary oxide compound CaGdCoO4-z which has an orthorhombic structure (Bmab) was found to be stable at this temperature. Five solid solution tie-line regions and six three-phase regions were determined in the CaO-½Gd2O3-CoOz system. A comparison of the phase diagrams of the CaO-½R2O3-CoOz (R = La, Sm and Gd) systems is provided.

The phase diagram of the La–Ca–Co–O system at 885 °C in air has been determined. The system consists of two materials that have interesting thermoelectric properties, namely, the misfit layered thermoelectric oxide solid solution, (Ca,La)3Co4O9, and Ca3Co2O6 which consists of 1D chains of alternating CoO6 trigonal prism and CoO6 octahedra. The reported La2CaO4 and the Ca-doped (La,Ca)2CoO4−z phases were not found at 885 °C. As a result of the absence of these phases, the phase diagram is significantly different from that reported at 1100 °C. Small solid solution regions of (La1−xCax)2O3−z (0 ≤ x ≤ 0.08), (Ca1−xLax)3Co4O9 (0 ≤ x ≤ 0.07), and (La1−xCax)CoO3−z (0 ≤ x ≤ 0.2) were established.

Chemical interaction between the Ba2YCu3O6+x superconductor and the CeO2 buffer layers employed in coated conductor architectures has been modeled experimentally by investigating phase equilibria on the Ba2YCu3O6+x CeO2 join at p O 2 = 100 Pa . This join is actually a non-binary join within the BaO Y2O3 CeO2 CuOx quaternary system. At an approximate mole ratio of Ba2YCu3O6+x : CeO2 = 40 : 60, a phase boundary was found to separate two four-phase regions. At the Ba2YCu3O6+x-rich side of the join, the four-phase region consists of Ba2YCu3O6+x, Ba(Ce1−zYz)O3−x, BaY2CuO5, and Cu2O; at the CeO2 rich side, the four phases were determined to be Ba(Ce1−zYz)O3−x, BaY2CuO5, Cu2O and CeO2. At 810 °C and p O 2 = 100 Pa , there appears to be negligible solid solution formation of the types Y1−zCezO3−x and Ce1−zYzO2−x. The minimum melting temperature along the Ba2YCu3O6+x CeO2 join was determined to be ≈860 °C. As part of this study, phase diagrams of the subsystems CeO2 Y2O3 CuOx, BaO CeO2 CuOx, and BaO Y2O3 CeO2 were also determined at 810 °C under 100 Pa p O 2 . The Y2O3 CeO2 CuOx diagram does not contain ternary phases and shows a tie-line from Y2O3 to the binary phase Y2Cu2O5−x. Similarly, the BaO CeO2 CuOx diagram contains no ternary phases, but has four tie-lines originating from BaCeO3 to Ba2CuO3+x, BaCuO2+x, BaCu2O2+x and CuOx. The BaO Y2O3 CeO2 system contains one ternary phase, the solid solution Ba(Ce1−zYz)O3−x ( 0 ⩽ z ⩽ 0.13 ), which crystallizes with the orthorhombic space group Pmcn (No. 62). Neutron Rietveld refinement of Ba(Ce0.94Y0.06)O2.84 [ Ba ( Ce 3 + 0.26 Ce 4 + 0.68 Y 0.06 ) O 2.84 ] gives lattice parameters of a = 8.7817 ( 4 ) A , b = 6.2360 ( 4 ) A , c = 6.2190 ( 3 ) A , V = 340.57 A 3 , Z = 4 . The structure consists of distorted corner-shared (Ce,Y)O6 octahedra that are tilted with respect to each other. Ba was found to have 9 nearest neighbors (distances

The phase diagrams of the BaO Gd 2 O 3 CuO z and BaO Er 2 O 3 CuO z systems were determined at 100 Pa (0.1% O 2 by volume, 810 °C) by using special apparatus and a procedure for preparing carbonate-free precursors based on BaO. The diagram of the BaO Er 2 O 3 CuO z system was confirmed to be similar to that of the Y-analog. The diagram of the BaO Gd 2 O 3 CuO z system exhibits different features as compared to the Er-analog. While the Er-system includes the Er 2 Cu 2 O 5 phase, the Gd-system involves the Gd 2 CuO 4 phase instead. The absence of the Ba 3 R 4 O 9 phase in the Gd-system affects the tie-line relations in the region bounded by BaO, BaGd 2 O 4 , BaGd 2 CuO 5 and Ba 6 GdCu 3 O z . In general, both the diagrams of the BaO Er 2 O 3 CuO z and of the BaO Gd 2 O 3 CuO z systems prepared under carbonate-free conditions are different from those obtained using BaCO 3 -derived starting materials. For applications of phase equilibria to coated conductor processing, phase diagrams constructed under carbonate-free conditions should be employed.