Synthesis, Structure, and Characterization of Two New Layered Mixed-Metal Phosphates, BaTeMO₄(PO₄) (M = Nb⁵⁺ or Ta⁵⁺)

Abstract

Two new isostructural mixed-metal phosphates, BaTeMO(4)(PO(4)) (M = Nb(5+) or Ta(5+)), have been synthesized as bulk phase powders and single crystals by standard solid-state techniques using BaCO(3), TeO(2), Nb(2)O(5) (or Ta(2)O(5)), and NH(4)H(2)PO(4) as reagents. The materials have novel layered crystal structures consisting of [M(5+)O(6/2)](-) corner-sharing octahedral chains that are connected to [Te(4+)O(4/2)](0) polyhedra and [P(5+)O(2/1)O(2/2)](-) tetrahedra. The Ba(2+) cations reside between the layers and maintain charge balance. The Te(4+) cations are in asymmetric coordination environments attributable to their lone pairs. The Nb(5+) distorts along the local C(4) direction of its octahedron resulting in a "short-long-short-long" Nb-O-Nb bond motif. The Nb(5+) cation displaces away from the oxide ligands that are bonded to Te(4+) or P(5+) cations, attributable to the structural rigidity of the TeO(4) and PO(4) polyhedra. Thus, the TeO(4) and PO(4) polyhedra support and reinforce the intraoctahedral distortion observed within the NbO(6) octahedra. Infrared and Raman spectroscopy, thermogravimetric analysis, and ion-exchange experiments are also presented. Crystal data: BaTeNbO(4)(PO(4)), orthorhombic, space group Pbca (No. 61), with a = 6.7351(9) A, b = 7.5540(10) A, c = 27.455(4) A, V = 1396.8(3) A(3), and Z = 8; BaTeTaO(4)(PO(4)), orthorhombic, space group Pbca (No. 61), with a = 6.734(2) A, b = 7.565(3) A, c = 27.435(9) A, V = 1372.6(8) A(3), and Z = 8.

K+ extraction induced phase evolution of KFeO2

“…Both of them suggest that the characteristic structures of KFeO 2 were dramatically damaged, resulting from the extraction of K + extraction. 29–31…”

Synthesis, Band and Crystal Structures, and Optical Properties of the Ternary Compound Mg2Te3O8

“…Until now, a large number of metal selenium (IV) and tellurium (IV) oxides with transition metal ions have been reported 9–12. The two units, TeO 3 2– and TeO 3+1 4– , are common motifs in tetravalent tellurium oxide chemistry, with the TeO 3 2– fragment previously observed in several compounds such as CuTe 2 O 5 ,9 CuTeO 3 ,13 NiTe 2 O 5 ,11 Nb 2 Te 4 O 13 ,12 Ga 2 Te 4 O 11 ,14 Ga 2 (TeO 3 ) 3 (H 2 O) 3 ,15 HLi 2 Ga 3 (TeO 3 ) 6 (H 2 O) 6 and Li 9 Ga 13 Te 21 O 66 ,16 whereas the TeO 3+1 4– fragment has been observed in CuTe 2 O 5 ,9 Te 6 O 11 Cl 2 ,17 V 2 MnTeO 7 18 and BaMTeO 4 (PO 4 ) (M = Nb, Ta) 19. Besides these two fragments, the mineral spiroffite that contains a Te 3 O 8 4– unit is another important motif in tellurium oxides, such as Zn 2 Te 3 O 8 ,20 Co 2 Te 3 O 8 ,21 Ni 2 Te 3 O 8 ,22 Mn 2 Te 3 O 8 23 and Cu 2 Te 3 O 8 24.…”

Cd3(PO4)(TePO6): A Novel Cadmium Tellurite‐Phosphate featuring a {[TePO6]3−}∞ Chain

“…Only Te 2 O(PO 4 ) 2 , K 2 (TeO)P 2 O 7 and Rb 2 (TeO)P 2 O 7 are NLO-active. [30,31] Other known tellurite-phosphates include Cs 2 (TeO)P 2 O 7 , [31] K 2 TeMo 2 O 6 (PO 4 ) 2 , [32] Ba 2 TeO(PO 4 ) 2 , [33] Ba 2 Cu 2 Te 2 P 2 O 13 , [34] Sr 2 Zn 3 Te 2 P 2 O 14 , [35] Na 3 Ca 4 (TeO 3 )(PO 4 ) 3 , [36] Fe 11 (TeO 3 ) 2 (TeO 4 ) 3 (PO 4 ) 2 O 4 Cl 3 , [37] Te 3 O 3 (PO 4 ) 2 , [38,39] Te 2 O 3 • HPO 4 , [40] Te 8 O 10 (PO 4 ) 4 , [41] BaTeMO 4 (PO 4 ) (M = Nb or Ta), [42] NaTePO 5 , SrTeP 2 O 8 , and Ba 2 TeP 2 O 9 . [43] By analyzing these compounds' compositions, it can be discovered that they either contain strong-ionic alkali/alkali-earth metal cations or don't contain any metal cations.…”