Synthesis and characterization of the phosphates Na1+xMg1+xCr2−x(PO4)3 (x=0; 0.2) and NaZnCr2(PO4)3 with the α-CrPO4 structure

Structural and Spectroscopic Studies of NaCuCr2(PO4)3: A Noncentrosymmetric Phosphate Belonging to the α-CrPO4-Type Compounds

“…First, the superposed NPD patterns showed peaks splitting around 35°and 80°and 117°( see enlarged parts in the top of Figure 1). 7,10,15 However, when a standard Shannon ionic radius of 0.73 Å is considered for Cu 2+ , the (202) peak positions for NaCuP clearly do not support such Vegard law, but rather a high contraction cell along (010) planes, leading to symmetry lowering, induced by an expected Jahn−Tellertype distortion for Cu 2+ cations. 30 Finally, when a lower symmetry was taken, the new peak appearing around 35°was indexed with a (hkl) reflection which is systematically absent for Imma symmetry (see the enlarged part in Figure 1 and Figure SI2c).…”

K1+2xNi1−xFe2(AsO4)3(x= 0,125): un nouvel arséniate à structure de type α-CrPO4

“…Notes: DNP = diffraction des neutrons sur poudre; DRXM = diffraction des rayons X sur moncristal; DRXP = diffraction des rayons X sur poudre; & = site vacant. Ré férences: (a) Glaum et al les deux exclusivement par des cations trivalents (Rittner & Glaum, 1994;Attfield et al, 1989), par une distribution statistique de cations di-et trivalents (Yahia et al, 2016;Souiwa et al, 2015b;Essehli et al, 2015), l'un par une ré partition statistique de cations di-et trivalents et l'autre uniquement par des cations di-ou trivalents (Souiwa et al, 2015a; Ben Smail & Zid, 2017b) ou l'un par des cations divalents et l'autre par des cations trivalents (Bouraima et al, 2016;Ouaatta et al, 2015;Alhakmi et al, 2013a,b;Assani et al, 2013;Korzenski et al, 1999;Hidouri et al, 2004;Kinomura et al, 1989). La derniè re ré partition cationique est observé e dans l'arsé niate objet de ce travail.…”

Synthesis and crystal structure of calcium dizinc iron(III) tris(orthophosphate), CaZn2Fe(PO4)3

“…Edge-sharing triangular bipyramidal ZnO 5 units linked to FeO 6 octahedra and to PO 4 tetrahedra, forming a layer perpendicular to the b axis. (Bouraima et al, 2015;Souiwa et al, 2015;Khmiyas et al, 2015) adopting the alluaudite structure type. In conclusion, we can say that the structure of this phosphate is similar to the alluaudite structure but with lower symmetry.…”