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The iron-manganese phosphate of composition (FeMn)(PO).2HO has been obtained as a single-phase product using hydrothermal methods and the structure has been determined by single crystal X-ray diffraction. The title compound is orthorhombic, Pbca, a = 8.720(1), b = 9.884(1), c = 10.114(2) Å, isostructural with strengite. The structure consists of a linkage of MO octahedra and PO tetrahedra. The octahedra are insular and are held together to form a three-dimensional structure by the tetrahedra. The crystal structure study revealed that (FeMn)(PO)⋅2HO exhibits a strong Jahn-Teller effect. The compound has been characterized by Raman and IR Spectroscopy, showing the bonds characteristic of the PO polyanions. Measurements by the electric permittivity revealed a peak at 350 K. Graphical Abstract: The iron-manganese phosphate of composition (FeMn)(PO)⋅2HO has been obtained as a single-phase product using hydrothermal methods and the structure has been determined by single crystal X-ray diffraction. The title compound is orthorhombic, Pbca, a = 8.720(1), b = 9.884(1), c = 10.114(2) Å, isostructural with strengite. The structure consists of a linkage of MO octahedra and PO tetrahedra. The octahedra are insular and are held together to form a three-dimensional structure by the tetrahedra. The crystal structure study revealed that (FeMn)(PO)⋅2HO exhibits a strong Jahn-Teller effect. The compound has been characterized by Raman and IR Spectroscopy, showing the bonds characteristic of the PO polyanions. Measurements by the electric permittivity revealed a peak at 350 K.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Single crystals of iron and manganese phosphate Fe 6.36Mn 0.64(PO 3(OH)) 4(PO 4) 2 was synthesized by hydrothermal method. The compound crystallizes in the Fe 7(PO 4) 6 structure type and is isotypic with the solid solution $$ {\text{M}}_{{7 - {\text{x}}}} {\text{M}}_{\text{x}}^{\prime} \left( {{\text{HPO}}_{4} } \right)_{4} \left( {{\text{PO}}_{4} } \right)_{2} $$ where M is Fe, Co, Mg, Mn. The compound is triclinic, P-1, a = 6.571(5), b = 7.993(3), c = 9.547(2) Ǻ, α = 103.97(1)°, β = 109.29(2)°, γ = 101.57(3)°. The structure is based on a three-dimensional framework of distorted edge-sharing MO 6 and MO 5 polyhedra, forming infinite chains, which are interlinked by corner-sharing with PO 4 tetrahedra. The formula unit is centrosymmetric, with all atoms in general positions except for one Fe atom, which has site symmetry −1. Graphical Abstract:: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Although Rb/Sr ratio and Sr isotopes are routinely modeled to determine petrogenetic processes and sources for granitic systems, the post-magmatic path and crystallization of Sr in granitic systems have not been thoroughly elucidated to date. In this study, we present the petrography, chemical composition and isotopic 87Sr/86 of Sr-bearing phosphates from the Nanping No. 31 pegmatite in Southeastern China, helping to characterize post-magmatic stages and geochemical recirculation of Sr in granitic systems. K-feldspar and primary apatites occur as major "primary Sr minerals", the occurrences of secondary Sr phosphates (strontiohurlbutite, palermoite and goyazite) and Sr-rich phosphates (apatites, hurlbutite, bertossaite and fluorarrojadite-(BaNa)) reflect the transport, concentration and recrystallization of Sr in granitic systems. The mobilization and recrystallization of Sr in granitic systems are mainly controlled by the variation in alkalinity of hydrothermal fluids. Two post-magmatic recirculations of Sr are proposed in the Nanping No. 31 pegmatite: (1) breakdown of the "primary Sr mineral" (K-feldspar and primary apatites) and crystallization of secondary Sr-bearing phases; and (2) replacement of secondary Sr-bearing phosphates and direct precipitation of later palermoite and goyazite from later Sr-rich fluids at low temperatures. The Sr isotope features of Sr-bearing phosphates suggest that the emplacement and consolidation processes of the Nanping pegmatite involved the participation of externally derived fluids. [ABSTRACT FROM AUTHOR]

The paper describing the new phosphate mineral correianevesite, recently published by Chukanov et al. (2014), clearly demonstrates the importance of pegmatite phosphates. For material scientists, these minerals are a source of new structure types; for petrologists, they constitute valuable tools necessary to accurately determine the temperature conditions prevailing during pegmatite differentiation processes. [ABSTRACT FROM AUTHOR]

This paper reports a new partially oxidized triphylite-type phosphate (lithium iron phosphate), which has been synthesized hydrothermally at 973 K and 0.1 GPa. The structure is similar to that of natural triphylite, LiFe(PO4), and is characterized by two chains of edge-sharing octahedra parallel to the b axis. The weakly distorted M1 octahedra contain Li atoms, whereas the more strongly distorted M2 octahedra contain FeII and FeIII atoms. Refined site occupancies and bond-valence analysis show the presence of FeIII and vacancies on the M2 site, mainly explained by the substitution mechanism 3 FeII = 2 FeIII + vacancies. [ABSTRACT FROM AUTHOR]

The first hydro­thermal synthesis of an Al-rich alluaudite-type compound, namely disodium dimanganese aluminium tris­(phosphate), which has been obtained at 1073 K and 0.1 GPa starting from the composition Na2Mn2Al(PO4)3, is reported. The crystal structure, which has been refined in the monoclinic C2/ c space group, is identical to that of natural alluaudite. The structure consists of kinked chains of edge-sharing M1 and M2 octa­hedra, which contain Mn2+ and Al3+ ions. The chains are stacked parallel to {101} and are connected in the b direction by the P1 and P2 tetra­hedra. These inter­connected chains produce channels parallel to c, which contain the large A1 and A2′ sites occupied by Na+ and Mn2+ ions. [ABSTRACT FROM AUTHOR]

Na 2 Mn 1.5 Fe 1.5 (PO 4 ) 3 (NMFP) dandelion sphere-like particles were successfully synthesized via a hydrothermal route without addition of any templates or surfactants (laboratory and pilot scales). The hydrothermal reactor (pilot scale) is equipped with stirrer for continuous agitation of reagents during the reaction. The obtained materials were characterized by X-ray diffraction, Mössbauer spectroscopy and Scanning electron microscopy. Results show that Na 2 Mn 1.5 Fe 1.5 (PO 4 ) 3 samples obtained from the reaction performed at laboratory scale have hierarchical dandelion sphere-like morphology and the dandelions consist of micro-/nano-rods. On the other hand, we obtained the self-assembly nano-rods morphology for the particles prepared using hydrothermal reactor. On the basis of the experimental results, a growth mechanism of Na 2 Mn 1.5 Fe 1.5 (PO 4 ) 3 self-assembly and dandelion sphere-like particles was proposed. Temperature and time of hydrothermal reaction are found to be crucial parameters in controlling the growth of Na 2 Mn 1.5 Fe 1.5 (PO 4 ) 3 particles. In addition, investigation of the effect of continuous stirring during the hydrothermal reaction shows that the reaction time can be optimized to obtain Na 2 Mn 1.5 Fe 1.5 (PO 4 ) 3 with small particles size. The influence of stirring on the NMFP morphology has been clearly evidenced. Indeed, the stirring leads to homogeneous particles. Cycling studies have shown that the synthesized Na 2 Mn 1.5 Fe 1.5 (PO 4 ) 3 dandelions materials exhibit specific discharge capacities of about 62 and 57 mAh g − 1 equivalent to about 1.2 and 1.05 lithium ions de-intercalated at C/15 and C/10 current density respectively. [ABSTRACT FROM AUTHOR]

Single crystals of iron and manganese phosphate Fe 6.36Mn 0.64(PO 3(OH)) 4(PO 4) 2 was synthesized by hydrothermal method. The compound crystallizes in the Fe 7(PO 4) 6 structure type and is isotypic with the solid solution $$ {\text{M}}_{{7 - {\text{x}}}} {\text{M}}_{\text{x}}^{\prime} \left( {{\text{HPO}}_{4} } \right)_{4} \left( {{\text{PO}}_{4} } \right)_{2} $$ where M is Fe, Co, Mg, Mn. The compound is triclinic, P-1, a = 6.571(5), b = 7.993(3), c = 9.547(2) Ǻ, α = 103.97(1)°, β = 109.29(2)°, γ = 101.57(3)°. The structure is based on a three-dimensional framework of distorted edge-sharing MO 6 and MO 5 polyhedra, forming infinite chains, which are interlinked by corner-sharing with PO 4 tetrahedra. The formula unit is centrosymmetric, with all atoms in general positions except for one Fe atom, which has site symmetry −1. Graphical Abstract:: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]