Observation of polytypism among the hydroxysalts of Ni(II) and Co(II)

A Time‐Resolved In Situ Quick‐XAS Investigation of Thermal Activation of Fischer–Tropsch Silica‐Supported Cobalt Catalysts

“…The ex-situ X-ray diffraction pattern recorded after activation at 120 8C (see the Supporting Information, Figure S4 [ [16][17][18][19] The intermediate formation of cobalt(II) hydroxynitrates upon activation in NO is confirmed by modelling of the in situ EXAFS using FEFF6 code. [20] The cluster for FEFF modelling was designed using the atomic positions and interatomic distances in Cu 2 A C H T U N G T R E N N U N G (NO 3 )(OH) 3 , [21] which is one of very few resolved structures of layered hydroxynitrates, and in which Co 2 + was substituted by Cu 2 + .…”

Synthesis and spectroscopic identification of nickel and cobalt layered hydroxides and hydroxynitrates

“…A solid-state urea flux method, similar to the thermolysis method, is described in the literature with both Co 2 (OH) 3 (NO 3 ) 64 and Co 3 (OH) 4 (NO 3 ) 2 65 compositions quoted to be formed. Infrared spectra presented in these studies suggest cyanate anions are also incorporated, so a solution urea flux method 29 for the preparation of layered hydroxyisocyanate phases of formula M 2 (OH) 3 (OCN) was also utilised to synthesise both a reported Co, and unknown Ni, analogue.…”

“…This compositional discrepancy may have caused the previous confusion where samples prepared by Ramesh using this method had both Co 2 (OH) 3 (NO 3 ) 64 and Co 3 (OH) 4 (NO 3 ) 2 compositions assigned in different publications. 36,64,65…”

Synthesis and thermal stability study of cobalt hydroxynitrate in different polytypic modifications

“…The following changes can be observed in the X-ray powder diffraction patterns of Co 2 (OH) 3 (NO 3 )-I and Co 2 (OH) 3 (NO 3 )-II: (i) first two successive lines could not be indexed to same (00ℓ) planes and (ii) the relative intensities and peak positions of (h0ℓ) reflections significantly differ from each other. In references [18,19], we have reported the anion mediated and cation mediated polytypism in case of cobalt hydroxysalts and nickel hydroxysalts. To the best of our knowledge there are no reports of cobalt hydroxynitrate having the chemical composition Co 2 (OH) 3 (NO 3 ) with the features explained above in their powder X-ray diffraction patterns.…”

“…The details of simulated X-ray powder diffraction patterns are reported in reference [19]. Although both samples obtained by methods-I and II have similar chemical composition, the nature of layer stacking sequence differs with respect to each other.…”