Structural and Spectroscopic Study of the (Mg, Ni)2(OH)(AsO4) Arsenates

Synthesis, Spectroscopic and Magnetic Properties of the Co2(OH)(PO4)1–x(AsO4)x [0 ≤ x ≤ 1] Solid Solution

“…The total weight loss measured during this second step (see Table 1) can be attributed to the loss of water obtained from the decomposition of two formula units of Co 2 (OH)(PO 4 ) 1-x (AsO 4 ) x in good agreement with the thermogravimetric analysis of M 2 (OH)XO 4 [X = P, As and M = Mg, Co] in air. [11,12] At about 700°C additional weight losses were not observed in the thermogravimetric curves. The X-ray diffraction patterns of the residues showed the presence of CoO (PDF no.…”

“…The decomposition curves of all compounds revealed weight losses in two steps [11,12] (see Supporting Information). The mean loss began above 600°C and depended on the substitution of AsO 4 by PO 4 (see Table 1).…”

“…[5] The adamite family, with formula [M 2 (O/OH)(XO 4 )], belongs to this group and takes its name from the natural compound Zn 2 (OH)AsO 4 . [6,7] The mineral phases such as [ eveite, Mn 2 (OH)AsO 4 , [8] libethenite, Cu 2 (OH)PO 4 , [9] zincolibethenite; (Cu,Zn) 2 (OH)PO 4 [10] and synthesized compounds such as (Mg,Ni) 2 (OH)AsO 4 , [11] Co 2 (OH)PO 4 , [12] Zn 2 (OH)PO 4 [12] and Co 2 (OH)AsO 4 [13] belong to this family. In the past, the difficulty in obtaining these compounds as pure phases had hindered the study of the physical properties, but in recent years hydrothermal techniques have been successfully used to prepare them in the laboratory.…”

Theory and experiment of the ESR of Co2+ in Zn2(OH)PO4 and Mg2(OH)AsO4

“…The necessary optical data were obtained from diffuse reflectance experiments, performed in a CARY 2415 UV-VIS-IR spectrometer, controlled with a VARIAN DS15 workstation, in the 5000 -50000 cm −1 wavenumber region [8,17]. The whole of the optical data used in this work was recorded at room temperatures, and all the relevant data that was necessary in the present work is in the tables I and II.…”

“…Figure 1 presents the experimental data for both the phosphate and the arsenate Co compounds studied in this paper. The system parameters of the octahedral complexes are slightly different from those already published [8,17], because they were obtained from the optical spectra after including a spin orbit correction in the ground orbital level [18].…”