Crystallographic tomography and molecular modelling of structured organic polycrystalline powders

Novel combination of crystallographic tomography and molecular modelling is used to examine the powder packing behaviour and crystal interactions for an organic polycrystalline powder bed.

Theoretical Studies of the Defect Structures for Cu(en)32+ and Ru(en)33+ Clusters in Tris(Ethylenediamine) Complexes

The local structures and spin Hamiltonian parameters (SHPs, g factors, and hyperfine structure constants) for the Cu(en)32+ and Ru(en)33+ clusters in ethylenediamine complexes are theoretically studied from perturbation formulae for tetragonally and trigonally elongated octahedral 3d9 and 4d5 clusters, respectively. Cu2+ centres I and II may experience the slight relative elongations ΔZ by about 0.005 and 0.007 Å in Zn(en)3(NO3)2 polycrystalline powder at 4.2 K and room temperature, respectively, along the C4 axis arising from the Jahn–Teller effect. For Ru(en)33+ cluster in the uniaxial [Rh(en)3Cl3]2NaCl ⋅ 6H2O single crystal doped with the single-crystal chloride salt [Ru(en)3]Cl3 ⋅ 4H2O, the local impurity–ligand bonding angle related to the C3 axis suffers a negative variation Δβ (≈−1.85°) with respect to the host βH in [Ru(en)3]Cl3 ⋅ 4H2O at 4 K. The features of SHPs and defect structures for the Cu(en)32+ and Ru(en)33+ clusters are also discussed in view of the different experimental temperatures.

Structure and thermal analysis of Ba0.5La0.5MnO3 polycrystalline powder

The structure and thermal properties of Ba[Formula: see text]La[Formula: see text]MnO3 polycrystalline powder have been investigated using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques. The structural studies have shown that Ba[Formula: see text]La[Formula: see text]MnO3 compound crystallizes in perovskite structure with Pm-3m cubic symmetry group. The lattice parameters were obtained to be a = b = c = 3.9073 Å. Mass changes have been observed from thermogravimetric (TG) and differential thermogravimetric (DTG) curves obtained in a wide temperature interval of 30–950[Formula: see text]C. Free energy and enthalpy changes for all observed transformations were determined. Observed endo and exo effects.