Preparative Methods in Inorganic Solid State Chemistry · Preparative Methods in Inorganic Solid State Chemistry Lecture series given at the Department of Inorganic Chemistry at University

Preparative Methods in Inorganic Solid State ChemistryLecture series given at the Department of Inorganic

Chemistry at University of Bonn, Germany (winter term 2014)

R. Glaum

Institut für Anorganische ChemieRheinische Friedrich-Wilhelms-Universität, Bonn (Germany)

http://www.glaum.chemie.uni-bonn.deemail: [email protected]

Contents

http://www.glaum.chemie.uni-bonn.de/

1. Basic ideas and problems about solid state reactions

2. Phase diagrams – Reading and understanding

3. Crystal Growth from a melt

4. Crystal Growth from a flux

5. Hydrothermal/solvothermal syntheses

7. Chemical Vapour Transport / Chemical Vapour Deposition

9. Commercial processes

8. Purification of Solids

6. Electrochemical Syntheses

Reactivity of Solids I.

A. R. West, Solid State Chemistry and ist Applications, Wiley & Sons, 1984.

MgOs + Al2O3,s = MgAl2O4,s

interdiffusion layer, thickness x

= k · x –1dxdt

x = (k' · t) –1/2

parabolic growth

2Al3+ – 3Mg2+ + 4MgOs = MgAl2O4,s

Interface MgO / MgAl2O4:

3Mg2+ – 2Al3+ + 4Al2O3,s = 3 MgAl2O4,s

Interface MgAl2O4,s / Al2O3,s:

Overall reaction:

Spinel MgIIAlIII2O4

cubic, a = 8,081 Å; building units: [MgIIO4] and [AlIIIO6]

O2– Al/Cr3+ Mg2+

chromophor [CrO6]


M. C. Escher: Fishes to Birds


Reactivity of Solids II.


NiOs + Al2O3,s = NiAl2O4,s

= k · x –1dxdt

x = (k' · t) –1/2

parabolic growth

2Al3+ – 3Ni2+ + 4NiOs = NiAl2O4,s

Interface NiO / NiAl2O4:

3Ni2+ – 2Al3+ + 4Al2O3,s = 3 NiAl2O4,s

Interface NiAl2O4,s / Al2O3,s:

Overall reaction:formation of NiAl2O4,s

x2 = k'' · t

Wagner mechanism

Reactivity of Solids III.


Problems:high activation temperature required for migration (diffusion) of atoms (ions) in a solid low thermal stability of some reaction products

Solutions:application of high temperatures („shake and bake“; „heat and beat“; brute force methods)providing large surface areas and short diffusion paths for a solid state reaction to happenuse of reactive precursor materialsSolid state reactions via more mobile phases (liquid or gas phase: reactions in melts, hydrothermal synthesis, CVT)

An Example: Synthesis of Na3N

M. Jansen, Angew. Chem. 2002, 114, 3897.

Na3N: anti-ReO3 structure type

Problem:3Nal + 1/2N2,g ≠ Na3Nsvery high activation temperaturefor the starting materials low thermal stability of thereaction product (Tdecomp ≤ 360°C)

Solution:Intimidly mixed atoms have to bereacted!Co-condensation of Na- and N-atomsT = 4K, followed by slow heating

Synthesis of RuSb3

A. L. E. Smalley, M. L. Jespersen, D. C. Johnson, Inorg. Chem. 2004, 43, 2486.

RuSb3: metastable Skutterudite

Problem:Rus + 3 Sbs ≠ RuSb3,s high activation temperature

for the educts (Rus)

Rus + 3 Sbs = RuSb2,s + ¼ Sb4,g

m.p.(Sb) = 631°C; b.p.(Sb) = 1750°C

RuSb3,s + RuSb2,s + Sbs

Synthesis of RuSb3

A. L. E. Smalley, M. L. Jespersen, D. C. Johnson, Inorg. Chem. 2004, 43, 2486.

Structures of ReO3 and Skutterudite

Skutterudite: CoAs3ReO3


An example from „real life“ (1)

S.C. Roy, planned Ph. D. thesis, 2014, University of Bonn.J. J. Moore, H. J. Feng, Prog. Mater. Sciences 1995, 39, 243-273.

Synthesis of CrIII(WVIO2)2(P2O7)(PO4) with high specific surface area ( low-temperature synthesis)

Starting materials: (NH4)6W12O39∙5H2O, 6 Cr(NO3)3∙9H2O,18(NH4)2HPO4, glycine, HNO3

The concept: formation of a gel (coordinationpolymer) upon evaporation;Glycin & Ammonia (fuel) reactwith HNO3 (oxidant) in a com-bustion reaction; formation ofgaseous products and of a non-volatile, amorphous solid

Diffusion barrier: problem and chance in solid state chemistry


S.C. Roy, planned Ph. D. thesis, 2014, University of Bonn.

Keggin-type compound2 (NH4)3PW12O40 + „Cr12P34O85“

ReO3-type compound(CrIII

0.167WVI0.333PV

0.500)O2.500.5

WVOPO4-type compound(CrIII

0.333WVI0.667)OPO4

Complete crystal chemical differentiationCrIII(WVIO2)2(P2O7)(PO4)

Keggin-Anion [P(Mo3O10)4]3–


Keggin-type compound2 (NH4)3PW12O40

+„Cr12P34O85“

S. C. Roy, planned Ph.D. Thesis 2014; P. Armand, D. Granier, A. van der Lee, Acta Crystallogr. 2007, E63, i191.

Close the balance for all components!

Cr12W24P36Ox

ReO3

ReO2(PO4)

ReVIO3 (a = 3.46 Å)WVIO3 (a = 3.84 Å)(CrIII

0.167WVI0.333PV

0.500)O2.50.5 (a = 3.78 Å)(CrIII

0.10VIV0.10WVI

0.30PV0.500)O2.50.5 ?

(CrIII0.10VV

0.10WVI0.30PV

0.500)O2.50O0.050.45 ?

S. C. Roy, planned Ph.D. Thesis 2014; R. Glaum, S. Islam et. al., Z. anorg. allg. Chem. 2013, 639, 2463.

ReO3 type structures containing phosphate?

WVOPO4: a = 6.5538(4)Å, b = 5.2237(8)Å, c = 11.1866(8) Å, β = 90.332(7)°

(CrIII0.33WVI

0.67)OPO4: a = 6.473(1)Å, b = 5.1569(4) Å, c = 11.049(2) Å, β = 90.11(1)°

Structure of (CrIII0.33WVI

0.67)OPO4

(CrIII0.33WVI

0.67)OPO4:(CrIII

0.20VIV0.20WVI

0.60)OPO4 ?(FeIII

0.20VIV0.20WVI

0.60)OPO4 ?

S. C. Roy, planned Ph.D. Thesis 2014.

C2/m, Z = 16, a = 37.016(3) Å, b = 12.756(1) Å, c = 9.428(1) Å, β =102.275(9)°

Structure of CrIII(WVIO2)2(P2O7)(PO4)

S. C. Roy, planned Ph.D. Thesis 2014.

Homogeneity range for VIII(WVIO2)2(P2O7)(PO4): (W1−xVx)OPO4, 0.33 ≤ x ≤ 0.40

Gibbs Phase Triangles I.

Gibbs phase triangle for system Ti / P / O


Gibbs Phase Triangles II.


Ternary phase diagrams A / B / C showing differenthomogeineity regions

Gibbs Phase Triangles III.

Gibbs phase triangle for system Co / P / O(ϑ = 800°C)

A CoOB Co3(PO4)2C Co2P2O7D Co2P4O12E CoP4O11F P4O10G P4O6H Co2PI CoPJ CoP2K CoP3

II IV

I

V

VI

III

Co II :Co, Co3(PO4)2, Co2PCo IV:Co2P, Co2P2O7, CoP

http://www.glaum.chemie.uni-bonn.de/M. Blum, K. Teske, R. Glaum, Z. Anorg. Allg. Chem. 2003, 629, 1709.

Oxygen Coexistence Pressure I.

K.Teske, H. Ullmann, N. Trofimenko, J. Thermal Anal., 49 ( 1997 ) S.1211-1220

flux control ( 5l / h )

carrier gas : argon + 1000 ppm hydrogenup stream

celldown stream

cell

moisturizer (opt.)

reactorwith sample

coulometric / potentiometric determination of p(O2)

Oxygen Coexistence Pressure II.

MessprinzipA. R. West, Solid State Chemistry and ist Applications, Wiley & Sons, 1984.

Oxygen Coexistence Pressure III.

Beispiel : CoIV (Co2P, Co2P2O7, CoP)

0,0008 0,0009 0,0010 0,0011

-24

-22

-20

-18

-16

-24

-22

-20

-18

-16

04. 02. 01Co4blm1; Auswertung mit I

log(

p(O

2))(p

(O2)

inat

m)

1/T [1/K]

log (p(O2))= 29.028 • 1/T + 7.614


Oxygen Coexistence Pressure IV.

1. What is the decomposition reaction?

2 / 7 Co2P2O7,s = 4 / 7 CoPs + O2,g

2. Thermodynamics :

∆rHT = (4/7∆fHT(CoPs) + ∆fHT(O2,g)) - 2/7 ∆fHT(Co2P2O7,s)

??

Van`t Hoff : RT

GK R∆−=ln

RS

RTHK RR ∆+

∆−=ln


Oxygen Coexistence Pressure V.

105329.0284.567

rH∆− = 10537,614

4.567rS∆

=

11053 132,6 kcal molRH −∆ = ⋅

1 11053 34,77 cal mol KrS − −∆ = ⋅ ⋅

CoP and Co2P2O7 are solids (a = 1), therefore Kp = p(O2)

than follows :log

4.567 4.567r rT T

pH S

KT

∆ ∆= − +

⋅

21

log (O ) 29.028 7.614pT

= − ⋅ +

comparison of coefficients yields:

and

eventually:


26

Cobaltoxide

homogeneity ranges of CoO(s) and Co3O4(s) are not includedCoO(s) melts at higher oxygen pressure, only Co2O3(s) is only badly characterised

Stability ranges of Co(s), CoO(s), and Co3O4(s) as functions of T and p(O2)

P. Schmidt, Thermodynamische Analyse der Existenzbereiche fester Phasen – Prinzipiender Syntheseplanung in der Anorganischen Festkörperchemie, Habilitationsschrift,TU Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1200397971615-40549

27

Oxygen co-existence pressures for binary systems I.


28


Oxygen Co-existence pressures for binary systems II.

29


Oxygen Co-existence pressures for binary systems III.

30


Oxygen Co-existence pressures for binary systems IV.

31

Metallo-thermic metal oxide reduction I.


Reduction of Fe2O3(s) by aluminium is no problem!

32


Reduction of HfO2(s) is impossible by aluminium but works with calcium!

Metallo-thermic metal oxide reduction II.

33


Ti1-xNbxO2 und Ti1-xSnxO2 sind möglich, Nb1-xSnxO2 nicht!

Mischkristallbildung TiO2, NbO2, SnO2

34

Redox behavior in a ternary system


cobalt(II) titanates(IV) are stabil, the combinations CoIII/TiIII, CoII/TiIII and CoII/TiII are not!

Simplification:components behave in the ternary system like the binaries!

35

Redox equilibria between oxides of iron and titanium


Only the combinations FeIII/TiIV and FeII/TiIV are stable!

36

Redox equilibria between oxides of iron and titanium


p(O2) rises from metallic titanium to iron(II) oxide.

I) II) III) IV)

sollid solutions:

FeIII2TiIV2O7

FeIII2TiIVO5

FeIITiIVO3FeII

2TiIVO4

37

Redox equilibria in the system Fe / V / O


In ternary oxides the combinations FeII/VIII, FeII,III/VIII,FeII,III/VIII,IV, FeIII/VIV and FeIII/VV are stable!

Phase Diagrams I.


incongruentmelting of ABand varioussolid solutions

Phase Diagram MgO – Al2O3


Crystal Growth Techniques I.


Czochralski Verneuil

pullingdirection

heater coil

crucible

growingcrystal

melt

O2 + powder

O2 + H2

flame

droplets

growing crystal

crystal support

(e.g.: Al2(SO4)3 + Cr2(SO4)3)

Verneuil‘s Technique

powder particels melt in the flame of an H2/O2 burner and crystallize on a crystal seedling; ruby and saphire are grown on an industrial scale applying Verneuil‘s technique

W. J. Moore, Der feste Zustand, Vieweg, 1977.

ca. 2

50 c

m

Synthetische Kristalle

Synthetische Kristalle besitzen die gleiche chemische Zusammensetzung wie natürlich gewachsene.

W. Schumann, „Edle Steine“, BLV Verlagsges. 1993.

Crystal Growth Techniques II.


Stockbarker Bridgman

zone melting

purification and crystallisation of metals

Flux Growth Techniques I.

B. R. Pamplin (ed.), Crystal Growth, Pergamon Press, 1975.

Reasons for application of the technique:

1) Desired material does not melt or has very high m.p.

2) Lowering of crystallization temperature

3) Improvement of crystal quality

4) Avoiding non-stoichiometry

Flux Growth Techniques II.


Choice of a flux:

1) High solubility for desired compound

2) High temperature coefficient of solubility

3) No miscibility with the compound to be crystallized

4) Inertness towards dissolved material and crucible

Flux Growth Techniques III.


Selected Examples - Oxides

Flux Growth Techniques IV.


Means of achieving crystallization from fluxed melts:

EF: temperature gradient(transport)

A,B,C:slow cooling

AD: evaporation of solventOstwald-Miers-Region

Flux Growth Techniques V.


Temperature profile (pendulum) for seed reduction:

Flux Growth Techniques VI.


Modified flux growth

cfg. zone melting

Flux Growth Techniques VII.

K.-Th. Wilke, J. Bohm, Kristallzüchtung, DVW 1988.

elements, borides,carbides, pnictidesfrom metallic fluxes

Hydrothermal Synthesis I.


tem

pera

ture

volumedensity

liquidphase

gas

phas

e

two phase

p, T diagramof water

critical point

Hydrothermal Synthesis II.


p, T diagramof water

constant volume

various percen-tages % of fillingof an autoclave

Hydrothermal Synthesis III.


Solubilities under hydrothermal conditions1a) SiO2 – NaOH 450°C1b) SiO2 – Na2CO3 450°C2a) Al2O3 – NaOH 430°C2b) Al2O3 – Na2CO3 430°C3) LiGaO2 – NaOH 400°C4a) ZnO – NaOH 360°C4b) ZnO – KOH 360°C5a) ZnS – KOH 450°C5b) ZnS – KOH 360°C6) KTa0.65Nb0.35O3 – KOH

650°C

Hydrothermal Synthesis IV.


Steel autoclaves

Hydrothermal Synthesis V.


Solubilitiy of SiO2 in water (left) and NaOH (right)

temperature

solu

bilit

y

250 atm

500 atm

750 atm

1000 atm

0,5n NaOH (80% filling)

Hydrothermal Synthesis VI.

B. R. Pamplin, Crystal Growth, Pergamon Press, 1975.

α - β Transition for Quartz

H. Bärnighausen, Commun. Math. Chem. 1984, 9, 139.

Structural relationship

P 62 2 2

α-SiO2 ↔ β-SiO2, TT = 573°C (2nd order)

t2

P 32 2 1

Chemical Vapour Transport I.


Chemical Vapour Transport: Migration of an otherwise immobilesolid in a chemical potential gradient via a mobile phase (gas orliquid)

Migration in a temperature gradient

Cl2,g Fe2O3,s

transport agentT(source)

T(sink)

isothermal transport; short distance transport; mineralisation effects;hydrothermal syntheses


Chemical Vapour Transport II.


Chemical Transport Physical Transport(Destillation, Sublimation)

without transport agent

direction always from hot to cold(T2 6 T1)

needs a transport agent (but: autotransport)

migration from hot to cold (T2 6T1) as well as from cold to hot(T1 6 T2) possible

Applications:van Arkel / de Boer - Methodpurification of solidshalogen lampscrystal growthmineral formation / Geology

Applications:purification of solids and liquidsfreeze drying

http://www.glaum.chemie.uni-bonn.de/akglhome

Natural Hematite Fe2O3



Chemical Vapour Transport III.


Questions:

Cl2,g Fe2O3,s

transport agent

Fe2O3,s + 3 Cl2,g = 2 FeCl3,g + 3/2 O2,g “transport reaction”

Which solids can be “transported”?Optimum experimental conditions (TA; T)?Speed of the migration (deposition); migration rate?

transportingspecies

FeCl3,g; O2,g

http://za0510pc5.chemie.uni-bonn.de/akglhome

Chemical Vapour Transport IV.



The migration direction is determined by the sign of the reactionenthalpy of the transport reaction:

endothermic, ∆RHT > 0 Y T2 6 T1

exothermic, ∆RHT < 0 Y T1 6 T2(Def.: T1 < T2)

Examples: Oxides / chlorineChlorides, bromides / Al2X6

Si (Ti, Fe and other metals) / iodine

endotheric

exothermic

Estimation of the sign of the reaction enthalpy by consideration ofbond energies of educts and products

Thermodynamics


Chemical Vapour Transport V.



“transport equilibrium”K

P FeCl P OP ClP =

⋅23

3 22

32

( ) ( )( )

/

(favorable: KP . 1; ∆RG . 0)

log ( ), ,

K TH

TS

PR T R T= −

⋅+

∆ ∆4 567 4 567

Gibbs-Helmholtz-equation∆ ∆ ∆R T R T R TG H T S= − ⋅(selection of T)

van t’Hoff-equation

Thermodynamics


Chemical Vapour Transport VI.


Experimental setting and definitions

ABK

ampoule dimensions: l . 11cm; q . 2,0 cm2; V . 22 cm3

V(source) : V(sink) . 2 : 1

Diffusion length s: 8 - 10 cm

SBK T(source)

T(sink)V(source)

V(sink)


Chemical Vapour Transport VII.


Calculation of partial pressures for CVT of Fe2O3,s using chlorine:

Fe2O3,s + 3 Cl2,g = 2 FeCl3,g + 3/2 O2,g

KP FeCl P O

P ClP =⋅2

33 2

23

2

( ) ( )( )

/

P(Cl2)T1, T2; P(FeCl3)T1, T2; P(O2)T1, T2; ΣPT1, T2 (8 unknown)

P FeCl P O( ) ( )343 2=

(2 Gl.)

(2 Gl.)

Σ PT1, T2 = P(Cl2)T1, T2 + P(FeCl3)T1, T2 + P(O2)T1, T2

n°(Cl2) = [(VT1/RT1)(P(Cl2)T1 + 3/2 P(FeCl3)T1] + [(VT2/RT2)(P(Cl2)T2 + 3/2 P(FeCl3)T2]

(2 Gl.)

Σ PT1 = Σ PT2


Chemical Vapour Transport VIII.


Partial pressure calculation for CVT of Fe2O3,s using chlorine:

Fe2O3,s + 3 Cl2,g = 2 FeCl3,g + 3/2 O2,g

P(Cl2)T1, T2; P(FeCl3)T1, T2; P(O2)T1, T2; ΣPT1, T2 (8 unknown pressures)

2 x -60,6

Exp. conditions: V = 22cm3; V(source) : V(sink) = 2 : 1 P°(Cl2) = 1 atm bei 298 K; n° = 0,982 mmol

3/2 x 0,03 x 0,0-196,82 x 82,2 3/2 x 49,03 x 53,320,9

∆RH298 = 75,6 [kcal / mol]

∆RS298 = 57,1 [cal / mol@K]


Chemical Vapour Transport IX.


Partial pressures as a function of temperature:

Ptotal P(Cl2) P(FeCl3) P(O2)T(source) T(sink)


Chemical Vapour Transport X.


Prerequisit for the application of the diffusion model:Diffusion between source and sink is the rate determining step of thewhole migration/deposition process

migration / deposition:(mechanism)

1.) Reaction of ABK with transport agent2.) evaporation of volatile species (1. phase transfer reaction)3.) “migration” from source to sink4.) seed formation5.) Crystal growth (2. phase transfer reaction)


Chemical Vapour Transport XI.


Transport formula derived by Harald Schäfer

, [ ],

nij

PP

T qs

D molAC= ⋅ ⋅

⋅⋅ ⋅ ⋅ −∆

Σ

0 8

0318 10

nA i, j

∆Pc

ΣP T q s

D0

Mole transported solid stoichiometric coefficients partial pressure difference [atm]

total pressure[atm] average temperature of diffusion path [K] cross section of diffusion path [cm2] length of diffusion path [cm] mean diffusion coefficient; 0,1 [cm2@sec-1]


Transport of Metals I.


Zrs + 4 Ig = ZrI4,g; 280 1450°C

Purification of Zirconium following van Arkel / de Boer:

(similarly: Ni, Cu, Fe, Cr, Si, Ti, Hf, Th, V, Nb, Ta, U)

Mos + 5/2 Cl2,g (5 Clg) = MoCl5,g; 400 1400°C

Ws + 3 Cl2,g (6 Clg) = WCl6,g; 400 1400°C

Nis + 4 COg = Ni(CO)4,g; 80 200°C

Purification of Nickel using the Mond-process:

(thermal stability of halogenide)

(vgl. H. Schäfer, Chemische Transportreaktionen, Verlag Chemie (1962))


Transport of Metals II.


e. g.: Ms + 2 Clg = MCl2,g; 800 1000°C

Transport of Fe and Ni using halogens (exothermic):

thermal instability of halides, e. g.:Rhs + 3/2 Cl2,g = RhCl3,g(s) (Y no transport)

Transport of noble metals:

(vgl. H. Schäfer et al., Z. anorg. allg. Chemie 286 (1956) 42.)

Transport of Fe and Ni using hydrogen halides (endothermic):e. g.: Ms + 2 HClg = MCl2,g + 2 H2,g; 1000 800°C

(vgl. H. Schäfer et al., Z. anorg. allg. Chemie 414 (1975) 137.)

increased volatility of halides by gas complex formation, e. g.:Rhs + 3/2 Cl2,g + Al2Cl6,g = RhAl2Cl9,g; 600 800°C


Transport of Oxides I.


Fe2O3,s + 3 Cl2,g = 2 FeCl3,g + 3/2 O2,g; 1000 900°C

Chlorine as transport agent:

Problem: a) frequently unfavourabel equilibria; b) transport of lower(stronly reducing oxides) is impossible Y Oxidation

TiO2,s + 2 Cl2,g = TiCl4,g + 2 O2,g; 900 800°C

MoO3,s + Cl2,g = MoO2Cl2,g + 1/2 O2,g; 900 800°C

Nb2O5,s + 3 Cl2,g = 2 NbOCl3,g + 3/2 O2,g; 1000 900°C

Solution: avoiding “free” oxygen; using non-oxidising transportagents (HCl, TeCl4, TaCl5, PI3)


Transport of Oxides II.


Fe2O3,s + 6 HClg = 2 FeCl3,g + 3 H2Og; 900 800°C

Non-oxidising transport agents:

Problems: occuring of solid (condensed) binary (halides) and ternary(tantalates; phosphates) phases

Ti3O5,s + 12 HClg = 3 TiCl4,g + 5 H2Og + H2,g; 900 800°C

MoO3,s + TeCl4,g = MoO2Cl2,g + TeOCl2,g; 900 800°C

Ta2O5,s + 3 TaCl5,g = 5 TaOCl3,g; 1000 900°C

3 TiO2,s + 4 PI3,g = 3 TiI4,g + P4O6,g; 900 800°C


Transport of Complex Oxides I.


CoNb2O6,s + 5/2 Cl2,g = CoCl2,g + NbOCl3,g + 5/2 O2,g

Transport behaviour similar to binary components:

lower solubility generally means lower solubility difference (lowermigration rate)

(Co1-xZnx)Os + Cl2,g = (1-x) CoCl2,g + x ZnCl2,g + 1/2 O2,g

Stabilisation of binary componenten by formation of the ternaryphase leeds to lower solubility in the gas phase of the ternary phasein comparison to the binary phases.

NiTiO3,s + 3 Cl2,g = NiCl2,g + TiCl4,g + 3/2 O2,g


Transport of Complex Oxides II.


ZnSO4,s + Cl2,g = ZnCl2,g + SO2,g + 1/2 O2,g

Chemical Vapour Transport of anhydrous sulfates:

Fe2(SO4)3,s + 3 Cl2,g = 2 FeCl3,g + 3 SO3,g + 3/2 O2,g

Fe2(SO4)3,s + 3 Cl2,g = 2 FeCl3,g + 3 SO2,g + 3 O2,g FeSO4,s + 2 HClg = FeCl3,g + SO2,g + H2Og + O2,g

(formation of Fe2O3,s)

NiSO4,s + Cl2,g = NiCl2,g + SO3,g + 1/2 O2,g

Al2(SO4)3,s + 3 SOCl2,g = 2 AlCl3,g + 6 SO2,g

2 VO(SO4)s + 3 Cl2,g = 2 VOCl3,g + 2 SO3,g + O2,g

NiSO4,s + PbCl2,g = PbSO4,s + 2 NiOs + SO2,g + Cl2,g


Transport of Halides I.


Caveat: migration in a temperature gradient frequently must be regarded as distillation or sublimation!

CrCl3,s + 1/2 Cl2,g = CrCl4,g; 800 700°C

MoBr3,s + MoBr5,g = 2 MoBr4,g; 475 250°C

Transport via higher halogenides (TR accompanied by oxidation):

(vgl. H. Schäfer, Z. anorg. allg. Chemie 414 (1975) 137.)

MoBr2,s + HgBr2,g = MoBr4,g; 1000 900°C

2 AlCl3,g = Al2Cl6,g

Transport via formation of gaseous complexes using AlCl3, AlI3,FeCl3 as complexing agent:

∆DimH298 = -30,1 [kcal / mol]; ∆DimS298 = -36,9 [cal / mol@K]


Transport of Halides II.


Dissoziation behaviour of Al2Cl6,g

(compare also dimerisation of CoCl2,g and other halides)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

400 600 800 1000 1200 1400 1600

temperature [K]

Al2Cl6,g

AlCl3,g


Transport of Halides III.



Transport of Halides IV.


Examples (synthesis of crystaline, anhydrous halogenides):

2 CrCl3,s + 3 Al2Cl6,g = 2 CrAl3Cl12,g

CoBr2,s + Al2Br6,g = CoAl2Br8,g; 400 300°C

( H. Schäfer et al., J. Less-Common Met. 61 (1978) 47.)

But:

CrCl2,s + Al2Cl6,g = CrAl2Cl8,g; 450 350°C

Pt (excess) + Br2,s + Al2Br6,g Y PtBr3,g; 400 350°C

Pd (excess) + I2,s + Al2I6,g Y Pd2Als + I2,g; T: 350 - 600°CTransport of Pd2Als: 375 600°C

( H. Schäfer, Angew. Chemie 88 (1976) 775.)


How to get metastable Solids?

When is a compound „stable“?

Synthetic pathways to metastable solids?

Zeolithe Mx/n[(AlO2)x(SiO2)y]·mH2O



[TO4]-Gruppen als Bausteine

Linde AUltramarin

Linde X/Y, FaujasitNa2Ca[Al4Si10O28]·20H2O4

Sodalith

β-Käfig

Ein molekularer Baukasten

Ein molekularer Baukasten

Löcher mit SiO2 drumherum

Linde A Linde X/Y, FaujasitNa2Ca[Al4Si10O28]·20H2O

Sodalith

Zeolithe besitzen Hohlräume, in die Moleküle oder Ioneneingelagert werden können.

Synthese von Zeolithen

SiO2haltige Verbindungenz.B. Wassergläser, Kieselsole

+ Natronlauge, Temperatur > 50°C, hydrothermale Reaktionsbedingungen

Zeolith

Al2O3haltige Verbindungenz.B. Aluminiumhydoxide, Aluminate, Kaoline

Anwendungen von ZeolithenEigenschaft Anwendung

AdsorptionIsolierglasKühlmittel

Dynamische Adsorption Trocknung und Reinigung von Erdgas, Spaltgas; Luftzerlegung

Trenneigenschaften Alkane / Isoalkane Trennung,

Ionenaustausch Waschmittel, Abwasserreinigung

Katalyse Fließbettcracken, Hydrocracken, Methanolumwandlung

Phosphates with Open Framework Structures

A. K. Cheetham, G. Férey, T. Loiseau, Angew. Chem. 1999, 111, 3466-3492.

VPI-5 (AlPO4)

M. E. Davis et al., Nature 1988, 331, 698.

~13 Å

Precipitation in the presence ofa structure dir-ecting reagent

Phosphates with Open Framework Structures

A. K. Cheetham et al., Chem. Commun. 2001, 859-860.

VSB-1 [Ni18(HPO4)14(OH)3F9(H3O/NH4)4 • 12 H2O

Effective catalyst for dehydrocyclodimerization of butadien!

Limited thermalstability of openframework structures!

Hydrothermal Synthesis of M2(H2P2O7)2

M. Blum, unpublished results, Univ. of Bonn, 2004.H. Thauern, Diploma Thesis, Univ. of Bonn, 2002.

M2(H2P2O7)2 = M2P4O12 + 2 H2O (M = Ni, Zn)2 M2(H2P2O7)2 = M(PO3)2 + 2 H2O (M = Zn)

Various Forms of FePO4

Y. Song, P. Y. Zavalij, M. Suzuki, M. S. Whittingham, Inorg. Chem. 2002, 41, 5778-5786.

Starting fromFePO4 • 2 H2O:

monoclinic and orthorhombicFePO4

[FeO6]

[FeO4]a

c

c

b

c

b

c

b

94

Aufbau eines Li-Ionen Akkumulators

M. Wohlfahrt-Mehrens, Zentrum für Sonnenenergie- und Wasserstoff-Forschung, Ulm.

Laden Entladen

Flüssige od. feste (Polymer) Elektrolyte

Alternative Elektroden-materialien?z.B.: LiFeIIPO4

Aufgeladen: CoIVO2 und LiC6

Entladen: LiCoIIIO2 und C6

Alternative Elektrolyte?

94

Various Forms of FePO4

A.S. Anderson, B. Kalska, L. Haggstrom, J. O. Thomas, Solid State Ionics 2000, 130, 41-52.

Delithiation of LiFePO4 (Olivine):preservation of thekinetically stable network structure

a

bmineralogy:(Fe1-xMnx)PO4 fromLi(Fe1-xMnx)PO4

new compounds:V2(PO4)3 fromLi3V2(PO4)3

Lithium batteries; electrode materials

The NASICON Structure Type

H. Kohler, H. Schulz, O.K. Mel'nikov, Mater. Res. Bull. 1983, 18, 1143-1152.

Sodium(Natrium) Super Ionic CONductor

[PO4] Tetrahedra[MO6] Octahedra

a

b

a

c

b

R 3 c; hcp array of [PO4] unitsβ-Fe2(SO4)3; NbIVNbV(PO4)3

e. g.: Na3.1Zr1.78 P1.76Si1.24O12

A. R. West, “Basic Solid State Chemistry”, 2nd ed., Wiley & Sons, 1999.

Intercalation / Deintercalation of Li

C. N. R. Rao & J. Gopalakrishnan, “New Directions in Solid State Chemistry”, Cambridge Univ. Press, 1986.

Intercalation / Deintercalation of Li

C. N. R. Rao & J. Gopalakrishnan, “New Directions in Solid State Chemistry”, Cambridge Univ. Press, 1986.

Documents

Preparative Methods in Inorganic Solid State Chemistry · Preparative Methods in Inorganic Solid State Chemistry Lecture series given at the Department of Inorganic Chemistry at University