Characterization of New Lead-Based Monophosphate Tungsten Bronzes, Pbx(PO2)4(WO3)2m(6≤m≤10)

• Published in: Journal of solid state chemistry Vol. 139; no. 2; pp. 362 - 372
• Main Authors: Roussel, P, Masset, A.C, Domengès, B, Maignan, A, Groult, D, Labbé, Ph
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01-09-1998; Elsevier
• Subjects: Chemical Sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Conductivity phenomena in semiconductors and insulators; Electronic transport in condensed matter; Exact sciences and technology; Inorganic chemistry; Inorganic compounds; Low-field transport and mobility; piezoresistance; Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Physics; Salts; Saturation moments and magnetic susceptibilities; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Heteropolysalt; Inorganic compounds; Lead tungstates; Electrical conductivity; XRD; Experimental study; Polyphosphates; Polytungstates; Magnetic susceptibility; Lead phosphates; Solid solutions; Charge density waves; Chemical composition; Bronze type compound; Quaternary compounds; TEM; Crystal structure
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1006/jssc.1998.7858

A new series of lead-based monophosphate tungsten bronzes (MPTBh), Pbx(PO2)4(WO3)2m, was isolated for 6≤m≤10 and characterized by X-ray diffraction, electron microscopy, and resistivity and magnetic susceptibility measurements. The crystal structure was solved form=7 from three-dimensional single-crystal X-ray data [Pb0.66P4W14O50: triclinic,A1,a=6.6015(3) Å,b=5.3156(4) Å,c=27.039(2) Å,α=90.208(6)°,β=96.757(5)°,γ=89.867(5)°,Z=1, finalR=2.16% for 4462 independent reflections withI>3.0σ(I)]. Lead atoms are distributed in cages bounded by 18 oxygen atoms, in a part that favors a PO4tetrahedron neighbor rather than a WO6octahedron neighbor. Consequently, Pb atoms exhibit an (3+5) eightfold coordination that takes into account the 6s2lone-pair stereoactivity. Resistivity measurements performed on oriented single crystals reveal quasi-two-dimensional metallic behavior for the entire temperature range investigated, 4.2 to 300 K. Magnetic susceptibility data indicate Pauli paramagnetic behavior. The results are compared with those of alkaline-based counterparts,Ax(PO2)4(WO3)2m(A=Na, K).