Crystallographic studies of olivine-related sarcopside-type solid solutions

Abstract

Solid solutions of Afe 3 (P0 4 ) 2 in Ni 3 (P0 4 ) 2 , with the olivine-related sarcopside structure (P2 1 /a), have been prepared and equilibrated at 1070 Κ (A/e = Mg, Μη, Fe, Co, Cu, or Zn). Accurate unit cell dimensions have been obtained from Guinier-Hägg photographic X-ray diffraction data. The cell volumes of the (Ni 1 _ z A/e i ) 3 (P0 4 ) 2 phases are correlated to the size and amount of Me 2 + . Rietveld full-profile refinements based on neutron powder diffraction data have been utilized to determine the distribution of cations among the two distinct octahedral sites M 1 and M 2. The preference for M 1 over M 2 is Ni 2+ > Co 2+ > Mg 2+ , Zn 2+ > Mn 2+ > > Fe 2+ .The cation distribution results are compared with corresponding results for olivines, orthopyroxenes, and some other oxosalt structures with metaloxygen octahedra similar in size and shape to those in olivine. It is concluded that the Ni 2+ /Me 2+ distributions in these structure types are mainly controlled by crystal field energies, while the size effects are small. Brought to you by | provisional account Unauthenticated Download Date | 7/1/15 11:32 PM A. G. Nord: Olivine-related solid solutions Nu(Si0j2 (Pbnm) *>a Ni 3 D(PO<) 2 (P2i/a)

Cation distribution studies of three (Ni, Mg) orthovanadates

“…CSD 53533, the names of the authors and the title of the paper. (Nord, 1984). Similar results were obtained for two other structure types, also containing two distinct A/0 6 octahedra, namely a (Ni,Mg) 2 P 4 O l2 tetrametaphosphate (Nord, 1983) and a (Ni,Mg) orthopyroxene (Ghose et al, 1975).…”

“…Nord and Ericsson, 1982;Nord, 1983Nord, , 1984. In some cases it has been possible to establish simple empirical rules for cation distributions, for instance as regards five-and six-coordinated metal sites (Nord and Ericsson, 1985).…”

Synthesis, Characterization, Electrochemistry, and In Situ X‐ray Diffraction Investigation of Ni3(PO4)2 as a Negative Electrode Material for Lithium‐Ion Batteries

“…Furthermore, orthophosphates with the general formula M 3 (PO 4 ) 2 (where M is a divalent transition metal) are an attractive family due to the possibility of hosting around six lithium ions with the reduction of M 2+ and therefore gaining more capacity. Orthophosphates were largely studied from a crystallographic point of view by many groups . However, orthophosphates were not much studied in literature as active electrode materials for energy storage in battery systems.…”

Photocatalytic hydrogen evolution over nickel cobalt bimetallic phosphate anchored graphitic carbon nitrides by regulation of the d-band electronic structure

“…The variable number n value of g-C 3 N 4 is 1 due to its direct-allowed transition. 19,20 21 The green, blue, red and violet balls represent Ni, Co, O, and P atoms, respectively. All the NiCo-Pi crystal structures with different Ni/Co molar ratios were geometrically optimized based on the above configuration.…”