Location of metallic elements in (Co1−xFex)2(OH)2(C8H4O4): use of MAD, neutron diffraction and 57Fe Mössbauer spectroscopy

Magnetism in the (Co1−xFex)2(OH)2(C8H4O4) solid solutions: a combined neutron diffraction and magnetic measurements study

“…Recently we have investigated four samples of the solid solution (Co 1Àx Fe x ) 2 (OH) 2 (C 8 H 4 O 4 ) x ¼ 0.25 (1), x ¼ 0.5 (2), x ¼ 0.75 (3); x ¼ 0.88 (4) (C2/m) by synchrotron radiation using multi-wavelength anomalous diffraction (MAD) and multipattern refinements in order to locate the two neighbor metallic elements Fe and Co. 5 Although there is no cation ordering, the two metallic sites M1 and M2 are preferentially occupied by Co and Fe respectively. This distribution is perfectly in agreement with neutron data and 57 Fe M€ ossbauer spectra at 100 K.…”

“…above T N ) have already been reported. 5 Refined parameters at 2 K are reported in Table 1. The high values of the R factors are due to the ''quality'' of the data (not deuterated samples).…”

From Hydrated Ni3(OH)2(C8H4O4)2(H2O)4 to Anhydrous Ni2(OH)2(C8H4O4): Impact of Structural Transformations on Magnetic Properties

“…Thus, compound Ni 3 (OH) 2 (C 8 H 4 O 4 ) 2 (H 2 O) 4 ( 1 ) was chosen not just because it only contains coordinated water molecules but also because it is very difficult to directly synthesize an anhydrous nickel terephthalate, Ni 2 (OH) 2 (C 8 H 4 O 4 ). The tetrahydrated compound was obtained by us in previous attempts to synthesize anhydrous Ni 2 (OH) 2 (tp) (tp = C 8 H 4 O 4 2– ), in order to complete the isostructural family M 2 (OH) 2 tp, where M = Co, Fe and Mn, Cu, V, and a Co–Fe solid solution. , The many attempts at direct synthesis of Ni 2 (OH) 2 tp were not successful. Other attempts involving hydrazine as a structuring agent were performed and led to formation of the unexpected new compound Ni(C 8 H 4 O 4 )(C 4 H 10 N 2 ) …”

Magnetic structure and dynamics of a strongly one-dimensionalcobaltIImetal-organic framework

“…Second, in addition to the intrinsic low-dimensionality, magnetic MOFs also show a large diversity in the type of topologies formed by the inter-connection of the magnetic ions (M) through the possible superexchange pathways (M-O-M pathways in most cases). Despite of the clear interest of these materials in the field of magnetism, hybrid frameworks are relatively little studied by neutron scattering techniques, [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] although these methods are commonly used to investigate the magnetic structures and excitations of purely inorganic compounds. This is partly due to the difficulty in synthesizing deuterated compounds when complex organic ligands are involved, and partly due to the weak magnetic contributions to the total neutron scattering from these materials.…”