Crystal chemistry and intracrystalline relationships of orthopyroxene in a suite of high pressure ultramafic nodules from the ‘Newer Volcanics’ of Victoria, Australia

1994 ◽  
Vol 58 (391) ◽  
pp. 325-332 ◽  
Author(s):  
Gianmario Molin ◽  
Marilena Stimpfl
Keyword(s):  
High Pressure ◽  
Melting Point ◽  
Crystal Chemistry ◽  
Site Occupancy ◽  
Mantle Melting ◽  
Cation Substitution ◽  
Crystal Chemical ◽  
Formula Unit

AbstractA suite of orthopyroxenes from spinel Iherzolite xenoliths associated with basanites occurring in the Victorian (Australia) post-Pliocene ‘Newer Volcanics’ province was investigated by means of a crystal chemical methodology which provides accurate site occupancy and site configuration parameters.The M1 configuration is essentially constrained by AlVI rather than Fe2+. In addition, Fe3+, Cr3+ and Ti4+ are confined to M1 (Molin, 1989) and AlIV to TB. M2 is controlled by FeM22+ ⇌ MgM2, constrained by (Fe2+ + Ca)M2 > 0.14 atoms per formula unit (p.f.u.). Cation substitution in TB and M2 constrains the sum of the volumes of the respective polyhedra VTB+VM2 to remain essentially constant. Therefore, M2 favours the retention of the large Fe2+ up to melting-point, causing non-ideality of this iron-depleted orthopyroxene. As a consequence, the investigated orthopyroxene can be considered an ultimate Fe2+ carrier during partial mantle melting.

C2/c pyroxene from two alkaline sodic suites (Western Ross Embayment – Antarctica): crystal chemical characterization and its petrologic significance

1997 ◽  
Vol 61 (406) ◽  
pp. 423-439 ◽  
Author(s):  
Gabriella Salviulo ◽  
Luciano Secco ◽  
Paolo Antonini ◽  
Enzo Michele Piccirillo
Keyword(s):  
Electron Probe ◽  
Alkali Basalt ◽  
Site Occupancy ◽  
Chemical Characterization ◽  
Poor Correlation ◽  
Crystal Chemical ◽  
Formula Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Lengths

AbstractTwo C2/c pyroxene suites from sodic alkaline rocks (Basanite-Phonolite: B-Ph and Alkali basalt-Trachyphonolite: AB-T) belonging to the McMurdo Volcanic Group (Mt. Melbourne province and Mt. Erebus, Antarctica) were investigated by single-crystal X-ray diffraction combined with electron probe microanalysis which together provide accurate site occupancy and site configuration parameters. Variations in site volumes distinguish the clinopyroxenes belonging to the more alkaline B-Ph suite from those of the AB-T suite. The former have higher VM2 and, for similar cell volume, lower VM1 and higher VT. In these C2/c pyroxenes, the bond lengths of M1 depend on R3+ content, necessary to balance AlIV in the T site. M1 geometric variations are similar for both B-Ph and AB-T suites. However, the M2 site is crucial for variations in polyhedral configurations. The increase in AlIV affects the shortest M2-O bond lengths in different ways depending on (Ca+Na) contents in the M2 site. Thus, the clinopyroxenes were distinguished in two different groups not related to the two suites. The first group is characterized by (Ca+Na) higher than 0.90 atoms per formula unit but shows a good positive correlation between the shortest M2-O bond lengths and AlIV content, at quite constant (Ca+Na). The second group has (Ca+Na) less than 0.90 atoms per formula unit but shows a poor correlation between the shortest M2-O bond lengths and AlIV content. In general, shortening of the longest M2-O bond lengths is associated with increase in AlIV. The cell and M1 volumes suggest that the clinopyroxenes, including the larger and sometimes resorbed macrocrysts, crystallized at a pressure lower than 5 kbar, fitting the petrography and evolved character of the rocks in question.

Crystal chemistry of lead aluminosilicate hollandite; a new high-pressure synthetic phase with octahedral Si

1995 ◽  
Vol 80 (9-10) ◽  
pp. 937-940 ◽  
Author(s):  
Robert T. Downs ◽  
Robert M. Hazen ◽  
Larry W. Finger ◽  
Tibor Gasparik
Keyword(s):  
High Pressure ◽  
Crystal Chemistry ◽  
Synthetic Phase

Simultaneous sintering of low-melting-point Mg with high-melting-point Ti via a novel one-step high-pressure solid-phase sintering strategy

2021 ◽  
Vol 858 ◽  
pp. 158344
Author(s):  
Xuecheng Cai ◽  
Shuaijun Ding ◽  
Zhongjie Li ◽  
Xin Zhang ◽  
Kangkang Wen ◽  
...  
Keyword(s):  
High Pressure ◽  
Melting Point ◽  
Solid Phase ◽  
High Melting ◽  
High Melting Point ◽  
One Step

High-Pressure Synthesis, Crystal Chemistry, and Ionic Conductivity of a Structural Polymorph of Li3BP2O8

2018 ◽  
Vol 57 (24) ◽  
pp. 15048-15050
Author(s):  
Eiichi Hirose ◽  
Kunimitsu Kataoka ◽  
Hiroshi Nagata ◽  
Junji Akimoto ◽  
Takuya Sasaki ◽  
...  
Keyword(s):  
High Pressure ◽  
Ionic Conductivity ◽  
Crystal Chemistry ◽  
High Pressure Synthesis ◽  
Pressure Synthesis

scholarly journals High-Pressure Syntheses and Crystal Chemistry of Postperovskite-Type Oxides and Fluorides

2014 ◽  
Vol 24 (3) ◽  
pp. 204-211
Author(s):  
Hiroshi KOJITANI ◽  
Yuichi SHIRAKO ◽  
Hitoshi YUSA ◽  
Masaki AKAOGI
Keyword(s):  
High Pressure ◽  
Crystal Chemistry

Eine synthetische Spezies zum Mineral Howardevansit mit Eisen anstelle von Kupfer: NaFe3V3O12 / A Synthetic Species of the Mineral Howardevansite with Copper Displacing Iron: NaFe3V3O12

1995 ◽  
Vol 50 (1) ◽  
pp. 51-55 ◽  
Author(s):  
F.-D. Martin ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Solid State ◽  
Melting Point ◽  
Single Crystals ◽  
Crystal Chemistry ◽  
Solid State Reaction ◽  
Space Group ◽  
Triclinic Symmetry ◽  
Symmetry Space ◽  
Symmetry Space Group

Single crystals of NaFe3V3O12 have been prepared by solid state reaction below the melting point of the reaction mixture. This compound is isotypic to the mineral Howardevansite but shows lower triclinic symmetry, space group C11–P1, a = 6.757(2), b = 8.155(2), c = 9.816(3) Å, α = 106.05(2), β = 104.401(9), γ = 102.09(2)°, Z = 2. The acentric space group is caused by the sodium positions, all other atoms comply with the space group P̄ of Howardevansite. The different ions are coordinated by O2- forming VO4 tetrahedra, FeO6 octahedra, trigonal FeO5 bipyramids and irregular NaO5 and NaO7 polyhedra, respectively. The crystal chemistry is discussed with respect to Howardevansite.

Crystal structures and electronic properties of Sn3N4 polymorphs synthesized via high-pressure nitridation of tin

CrystEngComm ◽  
2020 ◽  
Vol 22 (20) ◽  
pp. 3531-3538
Author(s):  
Ken Niwa ◽  
Tomoya Inagaki ◽  
Tetsu Ohsuna ◽  
Zheng Liu ◽  
Takuya Sasaki ◽  
...  
Keyword(s):  
High Pressure ◽  
Electronic Properties ◽  
Crystal Structures ◽  
Crystal Chemistry ◽  
Diamond Anvil Cell ◽  
Functional Materials ◽  
Group Iva ◽  
Diamond Anvil ◽  
Laser Heated ◽  
Insight Into

Sn3N4 polymorphs were synthesized via high-pressure nitridation of tin by means of laser-heated diamond anvil cell technique. This implies new insight into the crystal chemistry and functional materials of group IVA nitrides.

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