Weak ferromagnetism in cobalt oxalate crystals

Abstract

Microcrystals of diaquocobalt(II) oxalate have been synthesized by the coprecipitation reaction of aqueous solutions of Cobalt (II) bromide and oxalic acid. Chemical analysis and thermal experiments revealed that there is only one phase present. X-ray powder diffraction studies show that this compound is orthorhombic with space group Cccm. Molar susceptibility versus temperature measurements show the existence of an antiferromagnetic ordering, however, the hysteresis measured in magnetization measurements as a function of magnetic field reveals a weak ferromagnetic behavior.

Averrhoa carambola: A Renewable Source of Oxalic Acid for the Facile and Green Synthesis of Divalent Metal (Fe, Co, Ni, Zn, and Cu) Oxalates and Oxide Nanoparticles

“…To better elucidate the thermal behaviour of the complexes, a graph of the weight difference for consecutive rows against the temperature was plotted (Figure 7). The thermograms of four of the complexes (MC 2 O 4 ⋅ H 2 O, where M = Fe 2+ , Co 2+ , Ni 2+ , and Zn 2+ ) show two well defined steps of weight loss in agreement with reports in literature [24,28,31]. The first weight loss for FeC 2 O 4 ⋅ H 2 O (20.9%) occurs in the range 170-218 ∘ C. This is attributed to the elimination of two molecules of water of crystallization according to the theoretical value (19.69%).…”

“…The XRD spectra of the cobalt complexes synthesised at different temperatures are shown in Figure 4. The observed XRD patterns are similar to that of the standard prepared from commercial oxalic acid as well as to those reported in the literature [20,24]. This indicates that cobalt oxalate dihydrate was obtained at the different synthesis temperatures.…”

“…The two bands at 1359 and 1314 cm −1 are those of C-O symmetric stretching mode. The difference between ] as (COO) and ] sym (COO) stretching frequencies is 255 cm −1 indicating a bidentate or a terminal monodentate coordination mode of the oxalate ligand in the complexes[24]. The bands at 822 cm −1 is attributed to the bending vibration of O-C-O and the band at 745 cm −1 (absent in the spectrum of the Cu complex) is attributed to H-O-H rocking.…”

Characterization of Cobalt Oxalate Dihydrate Obtained from Spent Co-Mo/Al2O3 Hydrodesulfurization Catalyst

“…The % extraction values calculated using the ICP-OES analysis results of the solutions taken from the reactor at the end of the 3 hours experiment period are given in Table 3. When Table 3 [29]. The EDS analysis of the solid material includes the peaks of cobalt and oxygen.…”

Metamagnetism and weak ferromagnetism in nickel (II) oxalate crystals

“…This uncompensated antiferromagnetism produces weak ferromagnetism (WF). Recently, investigations in the quasi-onedimensional magnetic compound β − CoC 2 O 4 · 2H 2 O [6] revealed that the intra and interchain magnetic interactions tilt the spins, distorting the antiferromagnetic order and producing the WF.…”