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– Should there be one Repository or several Repositories for different types of systems?• Organics• Alloys• Sulfides• Oxides
– Viable Repository• Sufficiently large• Constantly updated: large amount of data are added
– Format of Repository• Mandatory fields• Recommended fields• Possibility to enter data in free format• It should be easy for authors to add data
Repository of Thermodynamic and Phase Equilibria Data
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– ID number for each reference• Never changes
– Reference• Chemical Abstracts standard
– Affiliations • It is essential to know the lab for data evaluation
– E-mail• For making inquiries
– Link to the article • Abstract• Is it possible to have a PDF copy?
– References and links to related articles• Description of the experimental method• Studies of the same system by the same group
Bibliographic Database
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– Who cited this article?• Science Citation Index accessed through the Web of Science• Scopus from Elsevier• Google Scholar• Microsoft Academic
– Blog• Inquiries sent to the authors and their replies• Discussion of data quality• Should not be anonymous?
– Notes and Editorial notes • Brief summary of the data made by any user• Editorial notes made by database managers
– Importance
Bibliographic Database
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– Elements in alphabetical order• For all studied systems and subsystems
– Search capabilities• Search for a particular system• Search for a particular system with subsystems
– System components• For example CaO-Al2O3-SiO2
– Phases • bcc, fcc for alloys• Major minerals for oxides (feldspar, olivine, pyroxene, etc.)
Studied Chemical System
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• Calorimetry Calorimitric measurements• CpHT Cp at high temperature (>298 K)• CpLT Cp at low temperature (<298 K)• H-H298 Heat content H(T)-H(298)• Hm Enthalpy of mixing• Hf Enthalpy of formation • Trans Enthalpy and Temperature of Fusion/Transformations
• EMF EMF measurements• Gf Gibbs energy of formation• Act Partial Gibbs energy and/or Activities• TD Thermodynamic properties• Entropy Entropy
• Isopiestic Isopiestic measurements• PO2 Partial Pressure of Oxygen• Pgas Partial Pressures (other than oxygen)• Ptot Total Vapour Pressure
Keywords
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• PD Phase Diagram• PE Phase Equilibria• Liquidus Liquidus equilibria• Solidus Solidus equilibria• SubSol Subsolidus equilibria• SlbLim Solubility Limit• InvPnt Invariant Points• MisGap Miscibility Gap• Distrib Distributions of minor elements among several phases• Fe2/Fe3 Fe2+/Fe3+ ratios
• Str Crystal Structure Data• LatPar Lattice Parameters• CD Cation Distribution• NonSt Nonstoichiometry, defects (vacancies, etc.)• Ordering Order-disorder transformations; Short-range ordering• Spectr Spectroscopic data
Keywords
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• Magn Magnetic properties (Tcurie, Tneel, magnetic moment, etc.)• SurfTen Surface Tension• Th-Cond Thermal Conductivity• Visc Viscosity• Diff Diffusion• Kin Kinetic data
• Vol Molar Volume or Density• dV/dP Compressibilities, Bulk Modulus• dV/dT Thermal Expancivities• High-P High Pressure data•• Model Modeling• Opt Optimization• Rev Review• Estim Estimation of Thermodynamic Properties• Exp Experimental methods• Appl Applications of computational thermodynamics
Keywords
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– Known structure with atomic coordinates• Space Group and Wyckoff Sequence
– Inorganic Crystal Structure Database from FIZ Karlsruhe (Leibniz Institute for Information Infrastructure)
– Depends in some space groups on the choice of origin
• We need to know what phases have related structures– Modeling of several phases as one solution
• May not tell the whole story
– Information on crystal structure is incomplete• What to store?• How to search?
Phase Identification
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Na2O Al2O3
SiO2 Solid solutions
NaAlO2–based solid solutions
NaAlSiO4–based nepheline and carnegieite solid solutions
Albite, NaAlSi3O8, end-member of multicomponent feldspar
Jadeite, NaAlSi2O6, end-member of multicomponent pyroxene
Na2O-Al2O3-SiO2 system
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S
N A
Na2O-Al2O3-SiO2 system
Liquid
Nepheline + High Albite (NaAlSi3O8) Quartz (SiO2) + High Albite
- #1196 Weber&Venero'70- SiO2- #1210 Schairer&Bowen'56- #1220 Greig&Barth'38- L+Carn-#1220 Greig&Barth'38- L+Neph-#1220 Greig&Barth'38- Carn-#1220 Greig&Barth'38- Neph-#1220 Greig&Barth'38
NaAlO2 solid solution (1)
NaAlO2s.s.(1)+Carnegieite
Tridymite (SiO2) + High Albite
Liquid+ Tridymite
NaAlSi3O8(s) + SiO2(s2)
Nepheline + Low Albite
NaAlO2 solid solution (2)
NaAlO2 s.s. (1)+Nepheline
NaAlO2 s.s. (2) + Nepheline
Liqu
id+
Cris
toba
lite
1526 (1526)
1119 (1119)
1061 (1062)1081 (1068)
1274
1254 (1254)
490 (490)
867
1465
467 (467)
1865 (1865)
1165
NaAlO2 - SiO2
mole SiO2/(NaAlO2+SiO2)
T(C
)
0 .2 .4 .6 .8 1200
400
600
800
1000
1200
1400
1600
1800
2000
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Feldspar Composes ~60% of the Earth’s crust
One of the most and best studied silicate solid solutions.
The phase transitions are among the most complex
NaAlSi3O8
AlbiteKAlSi3O8
Orthoclase
CaAl2Si2O8
Anorthite
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Alkali Feldspar
Most feldspar minerals and samples are metastable:
Equilibrium long-range ordering is not reached
NaAlSi3O8
AlbiteKAlSi3O8
Orthoclase
C2/mC2/m
CĪ
CĪ
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Plagioclase Feldspar C1 -> I1 phase transition
Probably 2nd order Different tetrahedral sequences of Al and Si in albite and anorthite
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Feldspar
− Al-Si ordering is very slow. • Most experimental measurements are made on metastable
samples (not under equilibrium conditions)
• Normally, disordered phases form first
− What database do we need?
• Thermodynamic properties of equilibrium (ordered) feldspars?
• Thermodynamic properties of metastable (more disordered) feldspars that initially form in phase equilibrium measurements?
− How can we identify the studied phase?
• Crystal structure
• Thermal history of samples
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Information to Store in the Database− Characterization of Samples
• Analysis (before and after the experiment)
• Thermal history
• Crucibles
• Atmosphere
− Unambiguous characterization of the data
• Store primary experimental data (e.g. EMF rather than recalculated thermodynamic properties)
• Units (e.g. pressure in bar or atm)
• Activities, ΔHf with respect to what phases (and at what T )?
• Data used to calculate the reported values
• 1st principles and MD data represent what particular measurable thermodynamic properties and at what conditions?
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B2O3-SiO2 system
Slag + Quartz(H)
Slag + Tridymite
Slag +
B2O3 + Quartz(L)
Slag
Rockett -1965_Liquid
Rockett -1965_Liq+Sol
Rockett -1965_Solids
Pichavant -1978_Liquid
Pichavant -1978_Liq+Sol
Charles -1968
Cristobalite
Slag + Quartz(L)
The BO1.5 - SiO2 phase diagram
mole fraction SiO2
T(C
)
0.0 0.2 0.4 0.6 0.8 1.0200
400
600
800
1000
1200
1400
1600
1800
2000
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B2O3-SiO2 system
Enthalpy of mixing in the BO1.5-SiO2 system at 700oC
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
0 0.2 0.4 0.6 0.8 1mole fraction SiO2
Hm
ix, k
J/m
ol
Hervig & Navrotsky, 1985
Calculated
Shul'ts et al., 1986 (25 C)
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B2O3-SiO2 system
Activity of BO1.5 in the BO1.5-SiO2 melts by mass-spectrometry
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.2 0.4 0.6 0.8 1mole fraction SiO2
Ac
tiv
ity
Boike, Hilpert and Muller, 1993 (1202 C)Calculated (1202 C)IdealShul'ts et al., 1986 (1315 C)Activity of SiO2
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B2O3-SiO2 system
Partial pressure of B2O3 over the BO1.5-SiO2 melts at 1315oC
-5
-4
-3
0 0.2 0.4 0.6 0.8 1mole fraction SiO2
lg [
P(B
2O3)
, atm
]
Calculated
Shul'ts et al., 1986
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B2O3-SiO2 system
Activities of SiO2 and BO1.5 in the BO1.5-SiO2 melts at 1450oC
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.2 0.4 0.6 0.8 1mole fraction SiO2
Ac
tiv
ity
Wang et al., 1996CalculatedIdealActivity SiO2
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Functionality
− It must be easy to enter data
• Copy and paste the whole table
• Plenty of space for headings
• Impossible to devise a universal set of fields to fill
− Graphs
• Any column of a table versus any other column
• Data from different data sets plotted on the same graph
− Tables that can be copied and paste into Excel • The whole table, not one number at a time