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Structure, Stability and Reactivity of Minerals
The main goals of this section can be grouped together
into the following categories:
•
Pressure-Temperature-Composition (PTx)
diagrams and physical properties of: ABO3 (AO-BO2; A2O3- B2O3),
ABO4 (AO2-BO2) and AB2O4 (AO-B2O3) oxides
• Catalytical properties of minerals on abiotic organic synthesis
a. Structure,
Stability and Reactivity of Minerals:
Pressure-Temperature-Composition (PTx) diagrams and physical
properties of: ABO3 (AO-BO2; A2O3- B2O3), ABO4 (AO2-BO2) and AB2O4 (AO-B2O3)
oxides
MALTA will address the
synthesis and structural studies of the cited oxides through high-pressure
synthesis (bell-type presses) and by means of in situ x-ray
diffraction and Raman scattering as a function of pressure and
temperature, and ab initio calculations, in order to determine the
P-T-X diagrams of compounds and to establish their stability ranges.
Besides MALTA facilities, the structural studies will require
the use of large facilities of synchrotron radiation and neutron
sources. The latter is particularly useful on dealing with
structural effects associated to magnetic ordering or involving
light elements. MALTA will prompt external links to facilitate
experimental proposals to ILL, LLB, ESRF, APS, DIAMOND, SOLEIL, in
which facilities MALTA’s scientists are regular users and also
developers of high-pressure facilities at beamlines (APS, D.
Errandonea). Additionally, a main goal to investigate in MALTA is the
physical properties of materials in connection to the
presence of transition metal ions and, particularly, how properties
change through structural phase transformations. In summary, with
the convergence of experimental and theoretical methodologies, many
of the structural and thermodynamic properties, and associated
phenomena of condensed matter can be explored and understood, and it
provides a basis for characterising, tailoring or predicting the
physical and chemical properties of materials with interest in both
Materials and Earth Sciences.
Structure, stability and reactivity of minerals (a) |
SCIENTIFIC SCOPE |
Example |
Field Coordinators
FJ Manjon |
Scientific Questions
- Further understanding the structure and stability of crystal phases at high pressure
- Exploring new phases in materials which can only be stabilized under given conditions of pressure and temperature
- Deeper understanding of C-Si analogies and its influence of the carbon cycle
- Synthesis of new materials with tailored properties of technological interest
- In situ determination of the physico-chemical properties of new phases |
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Leading Groups
UPV
UCAN - UV |
Supporting Groups
All |
Specific Goals
- Target systems: ABO3 (AO-BO2; A2O3- B2O3), ABO4 (AO2-BO2) and AB2O4 (AO-B2O3) oxides, with lightest A-B elements and, in particular, compounds involving carbon.
- Influence of inclusions of transition metal ions like Co, Fe, Cr, Ni, upon the structural and physical properties of these materials: structure and phase stability, transport properties (electrical and thermal), optical and magnetic properties (spin transition phenomena and electronic structure modification) and mechanical properties (hardness and elasticity)
- Study of the influence of these oxides in geodynamics and prospects on new materials applications |
Related Fields
Molecular systems
P-T sensors
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b. Structure,
Stability and Reactivity of Minerals: Catalytical properties of
minerals on abiotic organic synthesis
Although there is no direct
evidence to date of abiogenic petroleum formed within the crust, (which
is the essential prediction of the so-called abiogenic petroleum
theory), there is evidence exists for abiogenic (or abiotic)
creation of methane and other NOCH gases within the Earth.
High pressure and high
temperature experiments (between 5-11 GPa and 800-1800 K), show that
methane readily forms by reduction of carbonate under conditions
typical of the Earth’s mantle. The experiments showed the presence
of calcium oxide and magnetite, in addition to methane. It is
however recognized that abiogenic methane formation is prohibitively
slow in the absence of catalysts, and it has been suggested that
Ni-Fe alloys would provide the necessary reactivity.
These observations are
extraordinarily important because could allow hydrocarbons to form
and exist to a depth of 100 to 300 km. These studies point to the
suggestion that the Earth’s mantle could contain hydrocarbon
reserves larger in magnitude than in its crust, although precise
estimates of the extent of such a reservoir and its relationship to
the larger carbon cycle are unknown. In any case, such unexpected
results provide partial support to the controversial existence of an
abiogenic petroleum source. These observations reveal many
scientific challenges that merit further exploration within MALTA.
Work Plan III b |
SCIENTIFIC SCOPE |
Example |
Field Coordinators
A. Muñoz/J. Andrés |
Scientific Questions
- Pressure-induced chemical reactivity in minerals
- High pressure properties of the catalysts
- Formation of methane clathrates at deep sea |
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Leading Groups
ULL2 - UJI |
Supporting Groups
All |
Specific Goals
- High pressure structure and properties of Ni, Fe, and their alloys, sulphides and oxides.
- Catalytic properties of Ni, Fe, and their alloys, sulphides and oxides.
- Kinetics and stability of methane clathrates.
- High pressure reactivity of methane and other small hydrocarbons in presence of oxides of metals |
Related Fields
Clathrates
Oxides
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