0000000000146805
AUTHOR
Helmut Ehrenberg
Spin crossover in iron(II) tris(2-(2′-pyridyl)benzimidazole) complex monitored by variable temperature methods: synchrotron powder diffraction, DSC, IR spectra, Mössbauer spectra, and magnetic susceptibility
Abstract The thermal expansion of the spin crossover system [Fe(pybzim) 3 ](ClO 4 ) 2 · H 2 O (pybzim=2-(2 ′ -pyridyl)benzimidazole) has been determined from powder X-ray data between 50 and 250 K; the wavelength of the synchrotron source was 1.21888(1) A. The unit cell parameters of the triclinic crystal system were a =12.091 A, b =12.225 A, c =14.083 A, α =77.70°, β =80.35°, γ =74.35°, and V =1944.9 A 3 at 250 K. In addition to the linear thermal expansion of the unit cell volume, an extra expansion due to the low-spin (LS) to high-spin (HS) transition is observed. The V ( T ) function shows a sudden increase comparable with the step in the effective magnetic moment at the transition reg…
Magnetic and structural approach for understanding the electrochemical behavior of LiNi0.33Co0.33Mn0.33O2 positive electrode material
Abstract A systematic study has been performed to investigate the structural and magnetic changes in LiNi 0.33 Mn 0.33 Co 0.33 O 2 , a member of the LiNi y Mn y Co 1–2 y O 2 series, upon chemical lithium deintercalation. Structural characterization of the chemically delithiated Li x Ni 0.33 Mn 0.33 Co 0.33 O 2 samples indicates that the initial rhombohedral symmetry (α-NaFeO 2 type structure) is maintained in the whole 0.3 ≤ x ≤ 1.0 composition range. Less than 1% variation in the hexagonal unit cell volume was evidenced showing a good structural stability of this sample. SEM pictures of the delithiated phases confirm this stability. Indeed, the particle size average undergoes a small dec…