Rietveld refinement, electronic structure and ionic conductivity of Sr4La6(SiO4)6F2 and Sr4La6(SiO4)6O ceramics

Photochromic apatite skeletal structure materials: recent advances and potential applications

“…, a number of novel apatite-type compounds have been reported, including Ca 5 Y 3 Na 2 (PO 4 ) 5 (SiO 4 )F 2 , 88,89 Sr 9 La(PO 4 ) 5 (SiO 4 )F 2 , 90 Sr 4 La 6 (SiO 4 ) 6 F 2 , 91,92 NaLa 4 (SiO 4 ) 3 F, 93 SrMgY 3 (SiO 4 ) 3 F, 94 Ba 2 La 3 -(SiO 4 ) 3 Cl, 95 Ca 9 La(PO 4 ) 5 (SiO 4 )Cl 2 , 96 and so on. [97][98][99] Similarly, GeO 4…”

“…4, Ba 2 Ce 3 (SiO 4 ) 3 F can be thought of as the evolution phase of the Ca 5 (PO 4 ) 3 F prototype obtained by co-substitution of [2Ba 2+ + 3Ce 3+ + 3SiO 4 4− ] for [5Ca 2+ + 3PO 4 3− ]. Based on the substitution of SiO 4 4− for PO 4 3− , a number of novel apatite-type compounds have been reported, including Ca 5 Y 3 Na 2 (PO 4 ) 5 (SiO 4 )F 2 , 88,89 Sr 9 La(PO 4 ) 5 (SiO 4 )F 2 , 90 Sr 4 La 6 (SiO 4 ) 6 F 2 , 91,92 NaLa 4 (SiO 4 ) 3 F, 93 SrMgY 3 (SiO 4 ) 3 F, 94 Ba 2 La 3 (SiO 4 ) 3 Cl, 95 Ca 9 La(PO 4 ) 5 (SiO 4 )Cl 2 , 96 and so on. 97–99 Similarly, GeO 4 4− can be adopted to replace PO 4 3− in materials to design a new apatite structural material Ba 2 La 3 (GeO 4 ) 3 F, reported by Ma et al , 100 and also SO 4 2− and BO 4 3− are used to acquire other apatite-type materials, such as K 3 Ca 2 (SO 4 ) 3 F, 101 Na 3 Ca 2 (SO 4 ) 3 F, 102 K 4 Sb(SO 4 ) 3 Cl, 103 Na 3 Pb 2 (SO 4 ) 3 Cl, 104 Na 3 Ca 2 (SO 4 ) 3 Cl 105 and Ca 5 (BO 4 ) 3 F. 106–108…”

Synthesis, Rietveld refinements and electrical conductivity of news fluorobritholite based on lead Ca7-xPbxLa3(PO4)3(SiO4)3F2 (0 ≤ x ≤ 2)

“…Several studies have analyzed the occupancy of lanthanide ions between the two crystallographic sites in the apatitic structure. Several works indicate that the La atoms are distributed between the two crystallographic sites M(1) and M(2) in apatite structure, with a clear preference for the larger site M(2), demonstrating that the nature of the channel anion plays a significant role in the distribution of La 3+ between the two cationic sites [25,26]. Furthermore, Ardhaoui et al [27,28] indicated that the introduction of La 3+ in the apatite structure has a strong influence on its stability.…”