Synthesis and structure of Cu[sub 1. 35]Fe[sub 3](PO[sub 4])[sub 3] and Cu[sub 2]Mg[sub 3](PO[sub 4])[sub 3]: New mixed valence compounds of the alluaudite structure type

Journal Article · Fri Oct 01 00:00:00 EDT 1993 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1993.1290· OSTI ID:5067926

Maier, J ^[1]

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1. Max-Planck-Institut fuer Festkeorperforschung, Stuttgart (Germany)

This work is part of a continued program of exploring copper ion conductivity in solid phosphates. The first example of a phase in the copper-iron-phosphorous-oxygen quanternary system (Cu[sup 1]Cu[sup 11])[sub 1.35] (Fe[sup II],Fe[sup III])[sub 3](PO[sub 4])[sub 3], has been prepared by a high temperature synthesis technique. The crystal structure was determined from single-crystal data and shown to be of the alluaudite type, but with differences in copper coordination and occupancy compared to the alkali and alkaline earth metal analogues. It crystallizes in the monoclinic space group C2/c with lattice constants a = 11.894(4) [angstrom], b = 12.629(4) [angstrom], c = 6.440(1) [angstrom], [beta] = 115.24(2)[degrees], Z = 4. the structure contains chains of edge sharing FeO[sub 6] octahedra linked together via the common corners of PO[sub 4] tetrahedra, yielding two distinct one-dimensional channels for copper ion occupation. The compound exhibits both copper and iron mixed valency. The copper-magnesium phosphate analogue Cu[sup I]Cu[sup II]Mg[sub 3](PO[sub 4])[sub 3] has been prepared and is shown to be of the same structure type, a = 11.85(2) [angstrom], b = 12.55(2) [angstrom], c = 6.38(1) [angstrom], [beta] = 115.9(2)[degrees]. Magnetic susceptibility measurements confirm the presence of one Cu[sup 2+] (d[sup 9]) ion per unit formula with [mu][sub eff] = 1.78 [mu]B (>50 K).

• OSTI ID: 5067926
• Journal Information: Journal of Solid State Chemistry; (United States), Vol. 106:2; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COPPER PHOSPHATES
CRYSTAL STRUCTURE
IRON PHOSPHATES
MAGNESIUM PHOSPHATES
CHEMICAL PREPARATION
LATTICE PARAMETERS
MONOCLINIC LATTICES
ALKALINE EARTH METAL COMPOUNDS
COPPER COMPOUNDS
CRYSTAL LATTICES
IRON COMPOUNDS
MAGNESIUM COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties