Synthesis and Characterization of New Strontium Iron(II) Phosphates, SrFe2(PO4)2 and Sr9Fe1.5(PO4)7

Whitlockite-Related Phosphates Sr9A(PO4)7 (A=Sc, Cr, Fe, Ga, and In): Structure Refinement of Sr9In(PO4)7 with Synchrotron X-Ray Powder Diffraction Data

“…Figure 5 illustrates projections of these layers along the [010] direction with the pseudo-hexagonal unit cell expressed with dotted lines. The crystal structures of Ca 9 In(PO 4 ) 7 and Sr 9 Fe 1.5 (PO 4 ) 7 also consist of similar layers: layers I and II (25,35) (Fig. 6).…”

“…(Fig. 1a), the lattice parameters of Sr 9 A(PO 4 ) 7 were refined by the Rietveld method on the basis of the subcell with space group C2/m and a structural model derived from the crystal data of Sr 9 Fe 1.5 (PO 4 ) 7 (35). Table 1 lists refined lattice parameters of Sr 9 A(PO 4 ) 7 , showing that the ionic radii, r; of A 3+ ions in sixfold coordination (42) and unit-cell volumes, V; are strongly correlated.…”

Synthesis and X-ray Powder Diffraction Study of New Phosphates in the Cu3(PO4)2–Sr3(PO4)2 System: Sr1.9Cu4.1(PO4)4, Sr3Cu3(PO4)4, Sr2Cu(PO4)2, and Sr9.1Cu1.4(PO4)7

“…Moreover, examination of the hkl list for the observed re#ections in the R3c model of the crystal structure of Sr Cu (PO ) revealed that all l indexes were even. These facts allowed us to reduce the c parameter by a factor of 2 and to transform the atomic coordinates from space group R3c to R3 m (as R3cPR3 cPR3 m) according to the cell transformation a"!a, b"!b, 2c"c. This procedure was described in more details for the crystal structure re"nement of Sr Fe (PO ) (13). In the R3 m model, the M1 and M2, M4 and M6 sites, and the P2O and P3O tetrahedra of the Ca Cu (PO ) structure are equivalent.…”

“…The solid solutions Sr \V Fe V (PO ) (0.344x40. 43) with the -Sr (PO ) structure type and the compound SrFe (PO ) crystallizing in a monoclinic system were found in the Fe (PO ) }Sr (PO ) system (13). Crystal structures of compounds M \V Cu V (XO ) (M"Ca, Sr, Ba; X"P, V, As) usually di!er from crystal structures of compounds (similar in stoichiomerty) with other transition metals or magnesium due to the Jahn}Teller distortion caused by copper cations, for example, BaCu (PO ) (14) and BaNi (PO ) (15), Ba Cu(PO ) (16) and Ba Mg(PO ) (17), BaCu (VO ) (18) and BaMn (VO ) (19), and BaCu (AsO ) (20) and BaNi (AsO ) (21).…”

“…Binary phosphates of strontium and divalent metals (Mg, Mn, Fe, Co, Ni, Cu, Zn, and Cd) have been studied and characterized by di!erent authors. Crystal structures of -SrZn (PO ) (6), SrNi (PO ) (7), Sr Ni(PO ) (8), SrCo (PO ) (9), Sr Co(PO ) (10), SrMn (PO ) (11), Sr Cu (PO ) (12), and Sr Fe (PO ) (13) were determined. Phase diagrams M (PO ) }Sr (PO ) were investigated for M"Ca, Mg, Zn (1) and Cd (2).…”