11-09-2013

Materials Crystallography
Structure and Property Relations in Energy Materials
Sunday 29th September 2013

Mogens Christensen
Center for Materials Crystallography
Department of Chemistry & iNANO
Aarhus Universtet
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11-09-2013

Acknowledgements
Funding:Thank you for your kind attention!
Facilities:

ESRF
MAX-labSPring82

Henrik L. Andersen (Aarhus)2

11-09-2013

Conclusion
Synchrotron light is a very versatile tools for materials research
Atomic positions and occupancies:
Single crystal and powder diffraction- including resonant scattering
Vibration characteristics throughInelastic X-ray scattering
Growth properties of compounds
In situ studies33

11-09-2013

Overview
Thermoelectrics – a short introduction
Clathrates – the structure
Single crystal X-ray and neutron diffraction
Resonant diffraction
Zn4Sb3Single crystal diffraction
Powder diffraction

Skutterudites

X-ray and Neutron powder diffraction

Photons vs phonons Inelastic X-ray scattering in FeSb2
In situ X-ray diffraction studies of crystal growth44

11-09-2013

Thermoelectrics - Historical backgroundExperiment by T. Seebeck:

1820

1821
From “Electricity in The Service of Man“Experiment by H.C. Ørsted:

Magnetic field is observed=> heat causes a current flow.

IAn electrical current
induces a magnetic field.

1864

Thermoelectric generator
194 W at 54 V and 3.5 A.

1880 First street light in Broadway, New York1897 J. J. Thomas discovers the electron
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Thermoelectrics

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Thermoelectric figure of merit

Power factor S2σ=> Controlled by doping

The Electron Crystal
Electron thermal conductivity κe=> Fixed by Doping.
Lattice thermal conductivity κL⇒ The structure of the material

The Phonon Glass
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Application of Thermoelectrics - today

Improved materials could:
revolutionize the cooling industry
andincrease fuel efficiency by waste heat recovery.

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State-of-the-Art Thermoelectric Materials

Ba8Ga16Ge30

zT of 3-4 => paradigm shift in cooling industry.
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The clathrate structure
6d 2a

16i
24k

Host

Guest

Group IV/Group III:
(Si, Ge, Sn, Al, Ga, In)

Alkali-(Earth) metals(e.g. Na, Sr, Ba,…,Eu)

Transition metals(e.g. Ni, Pt, Cu, Ag, Au)

Halogens (invers)(Cl, Br, I)

associated withassociated with

Electron Crystal

Phonon Glasses

S2σ power factorκL lattice
thermal conductivity

6c

Wyckoff notation

Cages in the unit cell:• 6 tetrakaidecahedra• 2 dodecahedra

Key Features:
Low thermal conductivity
Tunablility of electrical properties
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The clathrate structure
6d 2a

Zintl stoichiometry:• Host is tetrahedrally bonded: 4e-/atom• Ionic guest donates valence electrons• Zintl: 4e-/atom · 46 host atoms = 184e-

Ba8Ga16+xGe30-x
16i
24k

6c

Wyckoff notation

Cages in the unit cell:• 6 tetrakaidecahedra• 2 dodecahedra

Ba donates 2e= 8·2 e- = 16eGa has 3 valence e- =16·3 e- = 48eGe has 4 valence e- =30·4 e- =120eTotal # e=184ex>0
Surplus of Ga⇓
p-type carriers

x<0
Surplus of Ge⇓
n-type carriers
111111-09-2013

The clathrate structure
Ba8Ga16+xGe30-x

6d 2a

Ba donates 2e= 8·2 e- = 16eGa has 3 valence e- =16·3 e- = 48eGe has 4 valence e- =30·4 e- =120eTotal # e=184e-

16i
24k

6c

Where are the host structure atoms?

Wyckoff notation

Cages in the unit cell:• 6 tetrakaidecahedra• 2 dodecahedra

What about the guest atoms?

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Look into the literature
24j
Random distribution of Ga/Ge
Guest atom position in the cage has been disputed
Ba8Ga16Ge30
6d
Sr8Ga16Ge30
24k/24j
Eu8Ga16Ge30
24k

24k
We decided to carry out a single crystal diffraction experiment.

Chakoumakos, et al. J. Alloys & Comp. 296 (2000) 80
Chakoumakos, et al. J. Alloys & Comp. 322 (2001) 127

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Single crystal diffraction

Refinement software
Shelx
Jana2006
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Host structure occupancies
Convention x-ray diffraction: not possible to distinguish Ga/Ge
Problem the scattering power is proportional to the number of electrons
Resonance scattering:
The form factor:f(θ,λ) = f(θ) + f’(λ) - if”(λ)f(θ) ∝ #e-: Ga(31e-) and Ge(32e-)

Ga edge Ge edge
f’ Ga

-11

-2

f’ Ge

-2

-10

Resonance data was collected at the Swiss-Norwegian Beamlines, ESRF.
M. Christensen et al., Accepted J. Am. Chem. Soc., (2006)

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Single crystal diffraction
Flourecence measurement of absorption edge

Grenoble
Good skiing resort

Nice hiking area

Ga edgeGe edge

f’ Ga
f” Ga

-8.0
0.7

-1.8
4.0

f’ Ge
f” Ge

-2.3
0.5

-8.9
0.7

World leading neutron source
Contrast:
Ga edge ~ Δf = 7eGe edge ~ Δf = 6e-World leading synchrotron
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11-09-2013

Host structure occupations
Ba8Ga16Ge30

Wyckoff notation:

Ba8Al16Ge30%

n-type p-type

czo

norm

flux

6c

76(1)

64(1)

97(1)

66(1)

56(1)

16i

16(1)

17(1)

44(1)

30(1)

24(1)

24k

37(1)

39(1)

5(1)

30(1)

40(1)

6c+24k

113

103

102

96

96

16i+24k

52

56

49

60

64

Occupation without causing Ga-Ga bonds.

6c-6c ≤ 100%
16i-16i ≤ 50%
24k-24k ≤ 50%
6c+24k ≤ 100%
16i+24k ≤ 50%

24k(50%)+6c(50%)
Ba82+Ga153+Ge314+: 185e16i(50%)+6c(100%)
Ba82+Ga143+Ge314+: 186e-

M. Christensen et al., Chem. Mater. 19 (2007) 4896

Preferably no bonds
between low valence atoms
Ga-Ga
Ga-Ge
Ge-Ge
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11-09-2013

Guest atom position
Host

Guest

Group IV/Group III:
(Si, Ge, Sn, Al, Ga, In)

Alkali-(Earth) metals(e.g. Na, Sr, Ba,…,Eu)

Transition metals(e.g. Ni, Pt, Cu, Ag, Au)

Halogens (invers)(Cl, Br, I)

Eu8Ga16Ge30

Eu2
Cages in the unit cell:• 6 tetrakaidecahedra• 2 dodecahedra
Fobs
Sales et al. Phys. Rev. B. 63 (2001) 245113
Bentien et al. Phys. Rev. B. 69 (2004) 045107

18

Avila et al. Phys. Rev. B. 74 (2006) 125109

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Time of flight single crystal neutron diffraction
SCD (Quasi-Laue diffractometer) at IPNS (Time-of-Flight)

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The clathrate structure

Fourier difference map
Fobs-Fcalc(÷Ba2)

Neutron single crystal diffraction

M. Christensen et al., J. Am. Chem. Soc. 128 (2006) 15657

Small difference in Ba position between
n-type Ba8Ga16Ge30 andp-type Ba8Ga16Ge30
Significant difference in host structure20

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11-09-2013

Single crystal neutron diffraction
Conventional

Ba guest atom nuclear density in Ba8Al16Ge30 prepared by:

%
6c
16i
24k

conv
66(1)
30(1)
30(1)

%
6c
16i
24k

czo
97(1)
44(1)
5(1)

Czochralski

20K

Relation between the host occupancies and guest atom nuclear density!
M. Christensen et al., Chem. Mater. 19 (2007) 4896

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11-09-2013

Thermoelectric properties
Conventional

Lattice thermal
Electrical
Seebeck
coefficientresistivity
conductivity

Czochralski

20K
Stoichiometry of the samples:• Conventional
Ba8Al15.5(2)Ge30.5(2)• Czochralski
Ba8Al14.8(2)Ge31.2(2)Zintl stoichiometry Ba8Al16Ge30
Normal => Higher resistivity
Larger Seebeck coefficient
M. Christensen et al., Chem. Mater. 19 (2007) 4896

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Modelling of thermal vibration
Can we do better than just the Fourier transform?
Harmonic crystal (Anisotropic ellipsoid)

Anharmonic potentials: Taylor expansion of the crystal potential
Isotropic
anisotropic

Anharmonic23

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Anharmonic modeling
Isolated atom anharmonic potential:# Parameters
Isotropic
Anisotropic
Cubic anharmonic
Quadratic anharmonic

1
6
10
15

Scalar
2nd rank tensor
3rd rank tensor
4th rank tensor

The number of free parameters=> high order data is needed for carrying out anharmonic refinements.
The symmetry of a specific atom may reduce the number of free varaiables.

Sr on 6d (0.25 0.5 0.0)

Number of free variables:
Anisotropic:
2
3rd Anharmonic1
4th Anharmonic4
Total ADPs
7
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High resolution data
Technique
Monochromatic

Advantage
High precision

Disadvantage
Slow, large crystals

Time-of-flight Laue

Fast, small crystals

Less precise

White beam Laue

Fast, small crystals

Less precise, less coverage

Laue diffraction experiment at KOALA at ANSTO

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11-09-2013

Single crystal refinements on Sr8Ga16Ge30
15K

Fobs

6d
isotropic

6d
24k
24k
6d
anisotropic isotropic anisotropic anharmonic

Laue diffraction data collected on KOALA, 508 unique reflections
Coverage about 70% to sinθ/λ = 1.0 Å-1

Can we do better than anharmonic refinements?
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11-09-2013

Maximum entropy method
Nuclear density from Fourier transform of structure factors (Fhkl)

Maximum entropy method
S = ∑ ρ N log
N

ρN
τN

ρN is the nuclear density in pixel N,
τN is the density of the prior distribution
The density maximization=> largest entropy=> flattest and most featureless density, which fits the data.
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11-09-2013

Single crystal refinements on Sr8Ga16Ge30
Fobs

6d
isotropic

6d
24k
24k
6d
anisotropic isotropic anisotropic anharmonic

MEM

Laue diffraction data collected on KOALA, 508 unique reflections
Coverage about 70% to sinθ/λ = 1.0 Å-1

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Conclusion – clathrates
Ba8Ga16Ge30 difference in thermal conductivity=> could not be explained by Ba guest atom position
Ba8Al16Ge30 remarkable difference in host and guest strucutre=> explain thermoelectric properties
Anharmonic vibration and MEM was used to describe disorderAcknowledgements:

Dan Bryan (UCSB)
Bo B. Iversen (Aarhus)
Martha Miller (IPNS)
Phil Pattison (SNBL)
Jacob Overgaard (Aarhus)
Art Schultz (IPNS)
Mette Schmøkel (Aarhus)
Hans-Peter Weber (SNBL)
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11-09-2013

Overview
Thermoelectrics – a short introduction
Clathrates – the structure
Single crystal X-ray and neutron diffraction
Resonant diffraction
Zn4Sb3Single crystal diffraction
Powder diffraction

Skutterudites

X-ray and Neutron powder diffraction

Photons vs phonons Inelastic X-ray scattering in FeSb2
In situ X-ray diffraction studies of crystal growth3030

11-09-2013

Thermoelectric properties of Zn4Sb3
Figure of merit zT

Thermal conductivity

Why is the thermal conductivity of Zn4Sb3 so low?

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The Crystal Structure of Zn4Sb3
Space Group : R-3c
Lattice constant: a = 12.223200(5)c = 12.416080(9)bOriginal model: Mayer
36f Zn 100%
Density
12c Sb 100%6.02 g/cm3
18e Sb 89%, Zn 11%
Empirical Density: 6.36 g/cm3
New model (single crystal)
36f Zn <100%
Density
12c Sb 100%
<6.36 g/cm3
18e Sb 100%
Interstitial Zn site ?

a

Sb

c

Zn Occupancy 90%[110] Axis

Zn Occupancy 6%32

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Powder diffraction of Zn4Sb3

Information from powder diffraction data
Lattice parameters
Peak positions
Atomic arrangements
Peak intensity
Displacement factors
Peak intensity (high 2θ)Crystallite size
Peak width
StrainPeak width
TextureRelative peak intensity
Relative phase fraction
Scale factor

What can we learn frompowder diffraction?

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11-09-2013

Powder diffraction of Zn4Sb3
Bragg’s law:2dsinθ = λStructure factor:

Fhkl = Σfi sofi exp(-Bisin2θhkl/λ2) exp(2πiGhkl·ri)

Rietveld function:

yci = ybi+ΣSφΣjφkLPφkOφk|Fφk|2ΩφkInformation from powder diffraction data
Lattice parameters
Peak positions d
Atomic arrangements
Peak intensity ri
Displacement factors
Peak intensity (high 2θ) Bi
Crystallite size
Peak width ΩφkStrainPeak width ΩφkTextureRelative peak intensity Oφk
Relative phase fraction
Scale factor Sφ34

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Intensity( a.r.b. units.)

Powder diffraction on Zn4Sb3

2θ
θ(degree))35

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The MEM Charge Densities of Zn4Sb3

2.0[e/Å3] equi-contour surface

36

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The MEM Charge Densities of Zn4Sb3(00l) plane
0.0 ~4.0,
0.2[e/Å3]stepZn Occ.90%
Zn Occ.6%

Zn Occ.90%(h00) plane
0.0 ~2.0,
0.2[e/Å3]stepZn Occ.6%3737

11-09-2013

Conclusion(00l) plane
0.0 ~4.0,
0.2[e/Å3]step(h00) plane
0.0 ~2.0,
0.2[e/Å3]step

Final model (single crystal + powder diffraction)
36f Zn 90%
Density
12c Sb 100%
6.37 g/cm3
18e Sb 100%3x Zn interstitial sites ~6%
Chemical formula Zn39Sb30
Empirical Density: 6.36 g/cm3
Electron counting:18e:
18 x Sb3- = 54 e12c:
12 x Sb2- = 24 e= 78 eTotal e⇒ 39 Zn2+ 32 from 36f
7 from interstitial Zn
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Conclusion
The low thermal conductivity could be explained byInterstial atoms in the structure
MEM help confirming the atomic positions
The new structure agrees with
Electron counting
Density in correspondance with measurements

Acknowledgements:

Bo B. Iversen (Aarhus)
Eiji Nishibori (SPring8)
Jeff Snyder (JPL)3939

11-09-2013

Overview
Thermoelectrics – a short introduction
Clathrates – the structure
Single crystal X-ray and neutron diffraction
Resonant diffraction
Zn4Sb3Single crystal diffraction
Powder diffraction

Skutterudites

X-ray and Neutron powder diffraction

Photons vs phonons Inelastic X-ray scattering in FeSb2
In situ X-ray diffraction studies of crystal growth4040

11-09-2013

Skutterudites
Skutterudites have promising thermoelectric properties:
Brutto formula: GCo4Sb12
Possible ways of optimization:
Filling – Guest atoms in the voids.
Nano structuring.
Substitution of Co by Fe or Ni.
X-Rays source problems:
Weak contrast between Fe, Ni, and Co.
Problem with conventional Cu Kα sources:
High Fluorescence due to Co and Fe.

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11-09-2013

X-rays vs. Neutrons
X-Rays; high background,comparable scattering length

Neutrons; isotope specificscattering length

General problems:
High background=>hides small impurities.
Broad peaks=>
difficult to resolve closely spaced peaks.
Comparable scattering power=>
hard to distinguish atoms.
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Skutterudite Ni1.2Co2.8Sb12
Neutron data measured at Studvik, Sweden

The data was Rietveld refinement
A difference Fourier map reveal an interstitial atom.
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Skutterudite Ni4xCo4(1-x)Sb12
Sample with x = 0.3 investigates by
Conventional Cu Kα
α radiation (λλ = 1.54Å))Neutron scattering (λ = 1.47Å)Synchrotron radiation (λ = 0.80Å)A combined refinement was carried out
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Case I; Ni4xCo4(1-x)Sb12
Phase analysis of combined refinement
Co3.76Ni0.24Sb12
72.7%
Co0.92Ni3.08Sb12
16.4%
NiSb2
5.8%
Sb
4.84%
CoSb
0.29%
Total amount of Co and Ni relative to Sb of 12
Powder phase analysis
Atomic absorptionNi
1.2(1)
1.2
Co
2.9(1)
3.0
Sb
12.0(1)
12.0
Theoretical calculation of phase stability supports the interpretation of the data.
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11-09-2013

Conclusion
Take care when analyzing powder diffraction data
Data does not always reveal what they are
Very good correspondence between atomic absorption andcareful phase identification.

Acknowledgement:

Luca Bertini (ISTM)
Carlo Gatti (ISTM)
Bo B. Iversen (Aarhus)
Mamoun Muhammed (KTH)
Eiji Nishibori (SPring8)
Häkon Rundlöf (Studsvik)
Mamoun Toprak (KTH)
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11-09-2013

Overview
Thermoelectrics – a short introduction
Clathrates – the structure
Single crystal X-ray and neutron diffraction
Resonant diffraction
Zn4Sb3Single crystal diffraction
Powder diffraction

Skutterudites

X-ray and Neutron powder diffraction

Photons vs phonons Inelastic X-ray scattering in FeSb2
In situ X-ray diffraction studies of crystal growth47

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11-09-2013

Photons vs Phonons
Photon”Massless” energy
Energy package in air/vacuum
Photons have direction
Photons have energy
Photons have polarization

PhononMass displacement
Energy package in solids
Phonons have direction k
Phonons have energy E
Phonons have polarization e

Phonon propagation

Longitudinal phonon

http://web.ua.es/en/urs/disclosure/seismic-wave-propagation.html

Transvers phonon

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Scattering - a reminder
Elastic scattering
Ein = Eoutkin = kout + G G integer Miller indicesTells us where atoms are

Inelastic scattering
Ein = Eout E ± ħωkin = kout + G G fractional Miller indicesTells us additionally what atoms do
Phonons/atomic vibrations
Molecular dynamics
Diffusion processes
Unfortunately the inelastic signal is very weakApproximately 106 times weaker than the elastic signal
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11-09-2013

Comparison: X-rays, Raman and neutrons
Phonons have typical energies of:
Phonon wave vectors G > 0.5 Å-1

X-ray:
λ ~ 1.3 Å
Qmax ~ 10 Å-1
Ein~10 keV∆E/Ein ~ 10-7
Sample size:<1mm3

E = 0-100 meVRaman (light):
λ ~ 500 nm
Qmax ~ 3·10-3 Å-1
Ein~ 2.5 eV∆E/Ein ~ 4·10-4

Neutron:λ ~ 2.8 Å
Qmax = 4.4 Å-1
Ein~10 meV∆E/Ein ~ 10-1<<1mm2>>1cm350

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11-09-2013

If this were a show on Discovery channel

Heaviest container ship: Emma Mærsk

captain∆E 1.3meV
captain−8== 5.4 ⋅10 −8
=
E
24keV
Emma Mærsk *10
51
Courtesy Sebastian Christensen

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Schematic instrument setup- Extremely well monochromatized incoming beam
- Very good angular resolution for energy detection

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Pictures from the experimental hutch:
The ID28 beamline @ ESRF
Sample position

Energy analyzer

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Detection and energy scans
The incoming energy is kept fixed andchange in outgoing energy is changed
The detected energy is changed by- Keeping angle fixed.
How
to change- Changing
d spacing energy?
by heating with mK
precision.
9 different Q-values are measured
simultaneous.
Analyzer crystal
Si(13,13,13)12000 individual crystals glued onto a spherical Si
substrate54

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11-09-2013

Study of FeSb2
Colossal Seebeck reported: -45000µV/K @ 10K
Calculations have so far not been able
to reproduce the peak Seebeck value

Experiments done in reflection mode
Crystal was cut to prepare a (100) surface next to (110)A. Bentien et al. EPL, 80 (2007) 17008

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11-09-2013

DFT calculations of phonon dispersion
Phonon dispersion calculations and electron-phonon coupling for FeSb2

Size ofindicates the strength of e-p-coupling at that point.
First we focused on the X point
M.S. Diakhate et al. Phys. Rev. B 84, 125210, (2011)57

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11-09-2013

How the data looks
X=(4.5,0,0)
Not all phonon branches are detected in agiven experimental setup due to symmetry
Data fitted with Lorentzians convoluted withexperimental resolution function.

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11-09-2013

Results
Signs of E-P-coupling when temperature
is increased- Broadening of phonon mode
- Decrease of phonon energy

Mode 4 shows significantly stronger
e-p-coupling than modes 2+3
Apparent broadening of mode 1 ismost likely an artifact of scatteringfrom ice

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11-09-2013

Conclusions on FeSb2 study
Theoretical calculations are confirmed athigh symmetry position.
Off-high symmetry positions - somediscrepancies that need to be explained.
Still no apparent explanation for the colossal
low temperature Seebeck.
Acknowledgement:

Sebastian Christensen (Aarhus)
Raphael Hermann (Jülich)
Michael Krisch (ESRF)
Anna Möchel (Juüich)Ilya Sergueev (ESRF)
Martin Søndergaard
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11-09-2013

Overview
Thermoelectrics – a short introduction
Clathrates – the structure
Single crystal X-ray and neutron diffraction
Resonant diffraction
Zn4Sb3Single crystal diffraction
Powder diffraction

Skutterudites

X-ray and Neutron powder diffraction

Photons vs phonons Inelastic X-ray scattering in FeSb2
In situ X-ray diffraction studies of crystal growth6160

11-09-2013

Pressure cooking

colleagues

Because you want your husband to say you’rechemistthe smartest, best cook ever, even though you spend
laboratory

less time in the kitchen!

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11-09-2013

Pressure cooker anno 2010
Synthesis in supercritical water

pc

Wash
Centrifuge
Dry

Tc

Fast heating rates=> instant nucleation=> minimal particle growth63

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11-09-2013

What happens in the synthesis?

r (Å)

Time (min)Synthesis
reactorChristoffer Tyrsted

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In situ X-ray diffraction
In situ X-ray characterization of synthesis products allow observation of=> Crystal growth

Growth of nanoparticles:
Peak intensity=> Growth information
Peak profile=> Size and shape information

Intensity (arb. units)

x60 speed2θ (º)

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Growth of nanoparticles
In situ growth of Fe2O3 nanoparticles
Pressure: 250 bar
Variable temperature

Time =

Integrate

Henrik Lyder Andersen

30sec
1min
2min
5min
7.5min
10min
15min
20min
25min
30min
0sec

Cascade66

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11-09-2013

Rietveld results
t=2min
T=320°C

Unit Cell Volume

t=5min
T=320°C

t=25min
T=320°C

Crystallite Size

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Avrami kinetics - Fits
Plot:
Reation rate as a function of time.
Reaction rate defined asV(t) / Vinf,
with Vinf being the final crystallite volume.
Fit:
Johnson-Mehl-Avrami equation:
f = V(t) / Vinf = 1-exp[-(k(t-t0))n]n Identifies the limiting mechanism for
growth and estimate the activation energy
from k.
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11-09-2013

Activation energy
Activation energy:
Calculated from the Arrhenius equation:k = k0exp(-Ea/(RT))ln(k) = -(Ea/RT)+ln(k0)Ea = - R*Δy/Δx = 67.4 kJ/mol
Previously reported:
0.71 eV = 68.5 kJ/mol

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Whole Powder Pattern Modeling (WPPM)
2M NH4-Fe(III)-Citrate, T=320°C
2min

5min

25min

Dav=2.94nm

Dav=9.09nm

Dav=14.86nm(T=320°C)§ Software: PM2K

70
* P. Scardi and M. Leoni, “Whole Powder Pattern Modelling,” Acta Crystallogr. A, 58, 190–200 (2002).
** Matteo Leoni, Rosa Di Maggio, Stefano Polizzi and Paolo Scardi, J. Am. Ceram. Soc., 87 [6] 1133–1140 (2004)69

11-09-2013

Transmission Electron Microscopy (TEM)
Sample: 2M NH4-Fe(III)-Citrate -> 25 min at 390°C

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Size comparison(T=370°C)(T=370°C)(T=390°C)

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Size comparison
Rietveld vs. WPPM sizes:* Same average size but different distributions!
-> High temperature + short reaction time gives narrower size distribution!
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Fouriertransform

3

6

9

12

15

-1
q (Å )

18

G(r) (Arb. units)

S(q) (Arb. units)

Total scattering

1

2

3

4

5

6

7

8

9

10

r (Å)

Pair Distribution Function
Gives information about:Precrystalline state
Atomic coordination
Size and shape
Kirsten Ørnsbjerg Jensen

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Pair distribution function analysis

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Conclusion• Particles size can be controlled by reaction temperatureor by substituting a surfactant free iron(III) source.
• Different mechanisms limit the growth depending on thereaction temperature.
• The size distributions broaden as reaction temperatureor reaction time is increased.
Acknowledgements:

Henrik Andersen (Aarhus)
Espen Bøjesen (Aarhus)
Bo B. Iversen (Aarhus)
Kirsten Jensen (Aarhus)
Nina Lock (Aarhus)
Christoffer Tyrsted (Aarhus)
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Conclusion
Synchrotron light is a very versatile tools for materials research
Atomic positions and occupancies:
Single crystal and powder diffraction- including resonant scattering
Vibration characteristics throughInelastic X-ray scattering
Growth properties of compounds
In situ studies
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