Structural studies of thortveitite-like Mn₂P₂O₇

σ-Dibarium Pyrophosphate

“…Cu (Robertson & Calvo, 1967, 1968, Co (Krishnamachari & Calvo, 1972;E1Belghitti, Boukhari & Holt, 1994), Ni (Lukaszewicz, 1967;Pietraszko & Lukaszewicz, 1968), Mg (Calvo, 1965a(Calvo, , 1967 and Zn (Robertson & Calvo, 1970;Calvo, 1965b) all follow this pattern, with Ni showing a further transition to a cr form in which octahedral Ni atoms with little or no axial distortion form planes of regular hexagons (Masse, Guitel & Durif, 1979). Fe (Stefanidis & Nord, 1982;Hoggins, Swinnea & Steinfink, 1983) and Mn (Stefanidis & Nord, 1984) are known in only one form.…”

Mercury(II) Diphosphate, Hg2P2O7

“…In contrast to the thortveitite-type structures, where adjacent metal-oxygen layers (e.g. Mn2P2OT; Stefanidis & Nord, 1984) are joined only by diphosphate groups, additional contacts from one [Hg-O] layer to another via common vertices (06) occur in Hg2P207 (Fig. 1).…”

(Mg1–xCrx)2P2O7, CaCrP2O7, SrCrP2O7 und BaCrP2O7 – Neue Diphosphate des zweiwertigen Chroms

“…Die quadratisch-pyramidale Anordnung der 5 Sauerstoffatome in der Koordinationsspha È re kann besser als 4+1-Koordination beschrieben werden: 2,04(2) A Ê £ d 1±4 (Cr±O) £ 2,07(2) A Ê , d 5 [35]. Die quadratisch-pyramidale Anordnung der 5 Sauerstoffatome in der Koordinationsspha È re kann besser als 4+1-Koordination beschrieben werden: 2,04(2) A Ê £ d 1±4 (Cr±O) £ 2,07(2) A Ê , d 5 [35].…”