THE PYROPHANITE-GEIKIELITE SOLID-SOLUTION SERIES: CRYSTAL STRUCTURES OF THE Mn1-xMgxTiO3 SERIES (0 < x < 0.7)

2006 ◽  
Vol 44 (5) ◽  
pp. 1099-1107 ◽  
Author(s):  
R. P. Liferovich ◽  
R. H. Mitchell
Keyword(s):  
Solid Solution ◽  
Crystal Structures ◽  
Solid Solution Series ◽  
Solution Series

True and brittle micas: composition and solid-solution series

2007 ◽  
Vol 71 (3) ◽  
pp. 285-320 ◽  
Author(s):  
G. Tischendorf ◽  
H.-J. Förster ◽  
B. Gottesmann ◽  
M. Rieder
Keyword(s):  
Solid Solution ◽  
Crystal Structures ◽  
Solid Solutions ◽  
Solid Solution Series ◽  
Octahedral Sheet ◽  
Tetrahedral Sheet ◽  
Solution Series ◽  
The Common ◽  
End Members ◽  
Graphical Presentation

AbstractMicas incorporate a wide variety of elements in their crystal structures. Elements occurring in significant concentrations in micas include: Si, IVAl, IVFe3+, B and Be in the tetrahedral sheet; Ti, VIAl, VIFe3+, Mn3+, Cr, V, Fe2+, Mn2+, Mg and Li in the octahedral sheet; K, Na, Rb, Cs, NH4, Ca and Ba in the interlayer; and O, OH, F, Cl and S as anions. Extensive substitutions within these groups of elements form compositionally varied micas as members of different solid-solution series. The most common true K micas (94% of almost 6750 mica analyses) belong to three dominant solid-solution series (phlogopite–annite, siderophyllite–polylithionite and muscovite–celadonite). Theirclassification parameters include: Mg/(Mg+Fetot) [=Mg#] formicas with VIR >2.5 a.p.f.u. and VIAl <0.5 a.p.f.u.; Fetot/(Fetot+Li) [=Fe#] formicas with VIR >2.5 a.p.f.u. and VIAl >0.5 a.p.f.u.; and VIAl/(VIAl+Fetot+Mg) [=Al#] formicas with VIR <2.5 a.p.f.u. The common true K micas plot predominantly within and between these series and have Mg6Li <0.3 a.p.f.u. Tainiolite is a mica with Mg6Li >0.7 a.p.f.u., or, fortr ansitional stages, 0.3–0.7 a.p.f.u. Some true K mica end-members, especially phlogopite, annite and muscovite, form binary solid solutions with non-K true micas and with brittle micas (6% of the micas studied). Graphical presentation of true K micas using the coordinates Mg minus Li (= mgli) and VIFetot+Mn+Ti minus VIAl (= feal) depends on theirclassification according to VIR and VIAl, complemented with the 50/50 rule.

A Review of the XRD Data of the Phases Present in the CaO-SrO-CuO System

1992 ◽  
Vol 7 (3) ◽  
pp. 142-148 ◽  
Author(s):  
Brian J. Reardon ◽  
Camden R. Hubbard
Keyword(s):  
Solid Solution ◽  
Ternary System ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Solid Solution Series ◽  
Powder Diffraction File ◽  
Reference Pattern ◽  
X Ray ◽  
Solution Series ◽  
Xrd Patterns

AbstractX-ray powder patterns for the phases in the CaO-SrO-CuO ternary system, along with the corresponding crystal structures, were obtained from the literature and from the Powder Diffraction File. Available XRD patterns were compared with each other and with a calculated pattern for each phase, yielding a recommended reference pattern. The simulated powder patterns presented here deal with the phases found within the (Ca,Sr)O, (Ca,Sr)2CuO3, (Ca,Sr)14Cu24O41, (Ca,Sr)CuO2, (Ca,Sr)Cu2O3, and (Ca,Sr)Cu2O2 solid solution series and are recommended for the Powder Diffraction File (PDF).

Geikielite–ecandrewsite solid solutions: synthesis and crystal structures of the Mg1−x Zn x TiO3 (0 ≤ x ≤ 0.8) series

2004 ◽  
Vol 60 (5) ◽  
pp. 496-501 ◽  
Author(s):  
Ruslan P. Liferovich ◽  
Roger H. Mitchell
Keyword(s):  
Solid Solution ◽  
Crystal Structures ◽  
Solid Solutions ◽  
Ambient Pressure ◽  
Unit Cell ◽  
Solid Solution Series ◽  
Coordination Polyhedra ◽  
Cell Parameters ◽  
Solution Series ◽  
Zn Content

The crystal structures of members of the geikielite–ecandrewsite solid solution series, Mg1 − x Zn x TiO3 (0 ≤ x ≤ 0.8 a.p.f.u. Zn; a.p.f.u. = atoms per formula unit), synthesized by ceramic methods in air at ambient pressure, have been characterized by Rietveld analysis of X-ray powder diffraction patterns. These synthetic titanates adopt an ordered R\overline 3 structure similar to that of ilmenite. The maximum solubility of Zn in MgTiO3 is considered to be ∼ 0.8 a.p.f.u. Zn, as compounds with greater Zn content could not be synthesized at ambient conditions. Data are given for the cell dimensions and atomic coordinates, together with bond lengths, volumes and distortion indices for all the coordination polyhedra. Within the solid-solution series unit-cell parameters and unit-cell volumes increase with Zn content. All compounds consist of distorted (Mg,Zn)O6 and TiO6 polyhedra and, in common with geikielite and ilmenite (sensu lato), TiO6 polyhedra are distorted to a greater extent than (Mg,Zn)O6. The displacements of (Mg,Zn) and Ti from the centers of their coordination polyhedra vary insignificantly with increasing Zn content. The interlayer distance across the vacant octahedral site in the TiO6 layer decreases slightly with the entry of the larger Zn2+ cation into the vi A site. The empirically obtained upper limit of the Goldschmidt tolerance factor (t) for A 2+ BO3 compounds adopting an ordered R\overline 3 structure is 0.755. The absence of natural solid solutions between geikielite and ecandrewsite seems to be due to the contrasting geochemistry of Mg and Zn rather than for crystallochemical reasons.

A Review of the XRD Data of the Phases Present in the CaO-SrO-PbO System

1992 ◽  
Vol 7 (2) ◽  
pp. 96-98 ◽  
Author(s):  
Brian J. Reardon ◽  
Camden R. Hubbard
Keyword(s):  
Solid Solution ◽  
Ternary System ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Solid Solution Series ◽  
Powder Diffraction File ◽  
Reference Pattern ◽  
X Ray ◽  
Solution Series ◽  
Xrd Patterns

AbstractX-ray powder patterns for the phases in the CaO-SrO-PbO ternary system, along with the corresponding crystal structures, were obtained from the literature and from the Powder Diffraction File. Available XRD patterns were compared with each other and with a simulated pattern for each phase, yielding a recommended reference pattern. The simulated powder patterns presented here deal with the phases found within the (Ca,Sr)2PbO4solid solution series and are recommended for the Powder Diffraction File (PDF).

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