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Updated: Mar 29, 2026
Spark Plasma Sintering Apparatus Used for the Formation of Strontium Titanate Bicrystals
Published on: February 9, 2017
Crystal structure of strontium dinickel iron orthophosphate
Said Ouaatta1, Abderrazzak Assani1, Mohamed Saadi1
1Laboratoire de Chimie du Solide Appliquée, Faculté des Sciences, Université Mohammed V, Avenue Ibn Battouta, BP 1014, Rabat, Morocco.
Abstract:
The title compound, SrNi2Fe(PO4)3, synthesized by solid-state reaction, crystallizes in an ordered variant of the α-CrPO4 structure. In the asymmetric unit, two O atoms are in general positions, whereas all others atoms are in special positions of the space group Imma: the Sr cation and one P atom occupy the Wyckoff position 4e (mm2), Fe is on 4b (2/m), Ni and the other P atom are on 8g (2), one O atom is on 8h (m) and the other on 8i (m). The three-dimensional framework of the crystal structure is built up by [PO4] tetra-hedra, [FeO6] octa-hedra and [Ni2O10] dimers of edge-sharing octa-hedra, linked through common corners or edges. This structure comprises two types of layers stacked alternately along the [100] direction. The first layer is formed by edge-sharing octa-hedra ([Ni2O10] dimer) linked to [PO4] tetra-hedra via common edges while the second layer is built up from a strontium row followed by infinite chains of alternating [PO4] tetra-hedra and FeO6 octa-hedra sharing apices. The layers are held together through vertices of [PO4] tetra-hedra and [FeO6] octa-hedra, leading to the appearance of two types of tunnels parallel to the a- and b-axis directions in which the Sr cations are located. Each Sr cation is surrounded by eight O atoms.
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