raman spectrum of vanadium-zirconia yellow pigment

This article was downloaded by: [Dalhousie University]On: 01 October 2013, At: 10:27Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UK

Spectroscopy Letters: An International Journal forRapid CommunicationPublication details, including instructions for authors and subscription information:http://www.tandfonline.com/loi/lstl20

Raman Spectrum of Vanadium Zirconia Yellow PigmentJules Tshishimbi Muya a , Ignace Kalala Kajimini a & Okuma Emile Kasende aa Faculty of Science, University of Kinshasa, Kinshasa XI, Democratic Republic of the CongoAccepted author version posted online: 05 Apr 2013.

To cite this article: Spectroscopy Letters (2013): Raman Spectrum of Vanadium Zirconia Yellow Pigment, SpectroscopyLetters: An International Journal for Rapid Communication, DOI: 10.1080/00387010.2013.782049

To link to this article: http://dx.doi.org/10.1080/00387010.2013.782049

Disclaimer: This is a version of an unedited manuscript that has been accepted for publication. As a serviceto authors and researchers we are providing this version of the accepted manuscript (AM). Copyediting,typesetting, and review of the resulting proof will be undertaken on this manuscript before final publication ofthe Version of Record (VoR). During production and pre-press, errors may be discovered which could affect thecontent, and all legal disclaimers that apply to the journal relate to this version also.

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) containedin the publications on our platform. However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of theContent. Any opinions and views expressed in this publication are the opinions and views of the authors, andare not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon andshould be independently verified with primary sources of information. Taylor and Francis shall not be liable forany losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoeveror howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use ofthe Content.

This article may be used for research, teaching, and private study purposes. Any substantial or systematicreproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in anyform to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

http://www.tandfonline.com/loi/lstl20

http://dx.doi.org/10.1080/00387010.2013.782049

http://www.tandfonline.com/page/terms-and-conditions

http://www.tandfonline.com/page/terms-and-conditions

ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT 1

Raman Spectrum of Vanadium Zirconia Yellow Pigment

Jules Tshishimbi Muya1, Ignace Kalala Kajimini1, Okuma Emile Kasende1

1Faculty of Science, University of Kinshasa,Kinshasa XI, Democratic Republic of the Congo

Corresponding author. Tel.: +243999905757; Email: [email protected]

Abstract Monoclinic vanadium-zirconia yellow pigments were prepared by gelling mixtures of zirconium n-propoxide and vanadyl acetylacetone. The nature of interactions between the host ion and the foreign cation in the vanadium-zirconia pigment was investigated in order to contribute to a better understanding of the origin of this pigmenting system using Raman-scattering measurements. The Raman spectra of powdered samples of the vanadium-zirconia pigment recorded between 100 and 1400 cm-1 show the peaks at 991, 701 and 403 cm-1 assigned to the asymmetric and symmetric stretching and bending vibrations of the V4+=O bonds, respectively. The assignment of these peaks was discussed by comparison with Raman spectra of vanadium oxides and on the basis of V-O bonds distances deduced from the Hardcastle and Wach’s equation and from the valence state of vanadium cation calculated by Brown in the valence sum rule. This suggests that the V4+ cations replace Zr4+ in sevenfold coordinated site in the monoclinic zirconia structure. The V4+ cation allowing the d-d electronic transition is related to the origin of the lemon yellow coloration.

KEYWORDS: Raman spectroscopy, vanadium zirconia, Yellow pigment

INTRODUCTION

There is a continuing interest in the vanadium-zirconium pigment because of its excellent

characteristics such as its very stable lemon yellow color. Despite many chemical and

spectroscopic investigations,[1–9] the origin of this pigmenting system is not yet fully

understood. Nevertheless, it has been ascertained by UV-visible diffuse reflectance[2,9]

and electron spin resonance[2,8] that the chemical state of vanadium in V-doped

monoclinic zirconia was V4+. The solubility of V4+ into monoclinic zirconia lattice

determined by X-ray microanalysis was about 5 mol % of vanadium (3.7 wt % as

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


V2O5).[9] The similarities between the diffuse reflectance spectrum of vanadium (IV) t-

butoxide (V(OBut)4) giving rise to an intense charge transfer band at 350 nm which is

very close to the visible region[10] and those of V4+ dissolved in the monoclinic

vanadium-zirconia solid solutions[9] seem to indicate that the yellow color of vanadium-

zirconia pigments could be related to the dissolved V4+ with partially filled d orbitals

allowing d-d transition in the near visible region of the UV–visible spectrum.

Changes of lattice parameters as a function of the nominal amount of vanadium observed

by X-ray diffraction in successive steps of reactions leading to the final monoclinic

vanadium-zirconia solid solution revealed that the mechanism of the solid solution

formation is substitutional. The dissolved vanadium ions replace Zr4+ in seven

coordinated sites in the monoclinic zirconia structure.[9] In other respects, the ability to

substitute one cation for another in a particular structure depends on several factors, such

as the dimension of the host/guest cation and the structural features of the pure oxide.

During the formation of mixed-oxide phases, the structural and energetic factors of the

individual constituents are profoundly modified.[11,12] As the host/guest cation should

preferably induce stress and structural defects, because of the difference in the ionic

radius between cations, the insertion of smaller zirconium cations in zirconia lattice

should lead to structural modification of the fluorite, which will be expressed by

modification of Raman spectrum with regard to ZrO2 spectrum. As Raman scattering is

sensitive to oxygen displacements due to its large polarizability, the pigment spectrum

has to be interpreted in terms of the symmetry change due to the oxygen displacement.

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


Furthermore, it should provide evidence for the occupation by vanadium of one of the

proposed sites.

Although the Raman spectrum of pure zirconia is well-documented,[13–15] no data is

available at this time on those of vanadium-zirconia pigment. However, it is worth noting

that apart from the significant role played by the vanadium-zirconia system in the field of

ceramic pigmenting systems, it can also act as a good catalyst. In this regard, it seems

worth mentioning that vibrational spectra of the catalysts of vanadium oxide dispersed on

the surface of zirconia have been subject to intense investigation in recent years.[16–31]

The aim of the present work is therefore to contribute to a better understanding of the

origin of this pigmenting system and to provide insight into the nature of interactions

between the host ion and the foreign cation in the vanadium zirconia pigment by Raman

Spectroscopy, a valuable tool for the characterization of dispersed metal oxides detecting

vibrational modes of surface and bulk structures.[20]

1. EXPERIMENTAL

1.1. Pigment Preparation

In order to change the thermal processing and lower the solid solution formation

temperature, the pigmenting system was prepared from gel precursors obtained by mixing

zirconium n-propoxide and vanadal acetylacetonate as previously reported by Alarcon.[9]

To a mixture of acetyl acetone (acacH) and n-propanol (n-PrOH), both supplied by

Aldrich without purification and kept under an atmosphere of Argon in a glovebox, a

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


solution of zirconium n-propoxide (ZnP, Zr (OC3H7)4 , purum, ~70% in propanol, from

Fulka) was added. Vanadyl acetylacetonate (VO(acac)2, C10H14O5V, purum, ≥ 97%,

from Fluka.) was then dissolved in the solution, continuously stirred, in the amount

required to obtain the desired V : Zr ratio in the final material (VxZr1-xO2, with x=0.0,

0.01, 0.03, 0.04 and 0.05). The molar ratios of n-PrOH/ZnP and acacH/ZnP used were

8/1 and 1/1, respectively. After removing the solution from the glovebox the hydrolysis

was performed by adding water. The molar ratio of H2O/ZnP used was 11/2. The

resulting solution, which was orange, was placed in a closed vessel and then left at 60°C

overnight in an oven. Further drying of gels was performed in an oven at 120°C. The

precursors were ground into powders using an agate mortar and pestle. Then each

precursor was pulverized and fired in air at 1065°C for 30 minutes, and rapidly cooled.

The resulting lemon yellow crystals were then investigated using Raman spectroscopic

analysis.

1.2. Raman Spectroscopy

The Raman spectra of V-ZrO2 solid solutions were recorded with the help of a Dilor

Labram spectrometer with 1800 grooves/mm diffractive grating using 514.5 nm radiation

from a Spectra-Physics argon ion laser for excitation. The scattered light was collected in

backscattering geometry by focusing a 10X objective (Olympus ULWD MS Plan 50X)

with a resolution of 4 cm-1. The Raman signal was detected with a charge-coupled device

(CCD, SDS 9000 photometrics). The laser power was varied from 100 to 250 mW.

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


The Raman spectrum of pure zirconia was compared to the one of vanadium-doped

material in order to identify the V-O vibrational modes of the latter. An empirical

correlation developed by Hardcastel and Wachs for relating Raman stretching frequencies

ν of vanadium-oxygen (V-O) bonds to their bond lengths R in vanadium oxide reference

compounds was used to estimate V-O bond distances in the pigment. This method

illustrated for vanadates of known structure and unknown structure are generally

applicable to all vanadates where medium-range order is absent. This empirical

correlation is based on least-squares exponential fit of crystallographicaly determined V-

O bond lengths to V-O Raman stretching frequencies as follow:

21.349 exp 1.9176 R (1)

A correction of 10 pm of the calculated values of V-O bond distance was made to

compensate the differences in ionic radii of V4+ and V5+ compounds. In Raman

spectroscopic investigation of the blue zircon vanadium pigment ZrSiO4:V4+, such as

adjustment was used by de Waal to compensate the differences in ionic radii because V4+

has a larger ionic radius than V5+ of the vanadate species for which the equation (1) had

been proposed initially.[33]

Furthermore, the Hardcastel and Wachs’s empirical correlation leads to a systematic

method for determining the coordination and bond length of vanadates. Indeed, in order

to relate the cation-oxygen bond length (R) and its bond valence (S), Brown and Shannon

have proposed the following expression based on the use of universal parameters

applicable to all crystals

NoS R / R (2)

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


where Ro and N are empirical parameters.[34] The Ro and N values proposed by Brown

and Wu for calculating vanadium-oxygen bond valence, S(V-O) being 1.79 and 5.1

respectively,[35] the contribution of each V-O bond, S(V-O), to valence state of vanadium

cation is

5.1V O ~ R /1.79S

(3)

and the valence sum rule discussed by Brown in estimating valence states of a vanadium

cation, VS, calculated by adding the contribution from each V-O bond, S(V-O) is

(V O)VS S (4)

2. RESULTS AND DISCUSSION

The Raman spectra of the vanadium-zirconia pigments VxZr1-xO2 with various amounts

of vanadium doped recorded between 100 and 1400 cm-1 are depicted in Figures 1–5. The

values of x for the various spectra are (a) 0.0, (b) 0.01, (b) 0.03 (c), 0.04 (d) and (e) 0.05.

Their Raman shifts compared with those of VO2 and V2O5 are listed in Table 1. Table 2

presents Raman stretching frequency of vanadium-oxygen (V-O), V-O calculated bond

distances and orders using Hardcastle and Wachs’s equation and calculated valence state

of the vanadium in the pigment by Wu’s empirical expression.

The Raman spectrum of pure Zirconia ZrO2 (VxZr1-xO2, with x=0.0) presented in Figure 1

is identical to the one widely reported[9] showing many sharp bands, characteristic of the

monoclinic phase. According to the literature, eighteen Raman active modes (9Ag + 9Bg)

are expected for the monoclinic fluorite structure of zirconia (space group P21/c).[13–15].

Compared with the Raman spectra of vanadium-zirconia pigments, the majority of the

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


bands observed in Raman spectra of vanadium-zirconia pigments, even with a slight shift

in the Raman frequency to lower wave numbers, can be attributed to pure zirconia as can

be seen from the comparison in Table 1. This suggests that the vanadium-ziconia pigment

has nearly the same monoclinic structure as the pure zirconia. That means the occlusion

of doping in zirconia net crystalline does not seem to induce important perturbations on

ZrO2 bonds, the vanadium (IV) ions replace Zr4+ in seven coordinated sites in the

monoclinic zirconia structure. The slight shift in Raman frequencies to lower wave

numbers observed in the spectra of vanadium-zirconia pigment is consistent with the

contraction of the unit cell observed as a large ion is replaced by a smaller one.[9]

Moreover, as can be seen from Figure 1, four peaks missing in the pure zirconia spectrum

are observed at 991, 701, 403 and 281 cm-1 in the vanadium-zirconia pigment spectra

(Figures 2–5). The most noticeable change is the enhancement of the relative intensity of

these peaks with the amount of vanadium doped. In order to examine whether these

developing Raman peaks at 991, 701, 403 and 281 cm-1 with vanadium doped are directly

related to bonds involving vanadium ions, we compared the frequencies of these peaks

with those of known vanadium oxides in Table 1. It appeared that the frequency of the

peak at 991 cm-1 in the Raman spectra of vanadium-zirconia pigment is close to the ones

at 992 and 1000 cm-1 in the Raman spectra of VO2[33] and V2O5 in crystalline form,[36]

respectively assigned to (V=O) stretching mode. The peak at 701 cm-1 in the pigment

spectra could be associated with the ones at 692 and 706 cm-1 in the Raman spectra of

VO2[33] and V2O5

[36] respectively. The frequency of the peak at 403 cm-1 in the Raman

Spectra of vanadium-zirconia pigment is near to the one of the peak at 405 cm-1 in the

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


Raman spectra of V2O5 in crystalline form ascribed to the bending vibration of the V=O

bond. [26] Although the peak at 281 cm-1 in the Raman Spectra of vanadium-zirconia

pigment is near to the one at 283 cm-1 in the Raman spectra of V2O5 ascribed to bending

vibration of the V=O bonds, a deep theoretical analysis of the electronic structure of V-

ZrO2 is need to confirm this assignment in the Raman Spectra of vanadium-zirconia

pigment. Based on these observations, we surmise that the peaks at 991, 701 and 404 cm-

1 are likely due to the asymmetric and symmetric stretching and bending vibrations of the

V4+=O bonds, respectively.

To further support this hypothesis, the interactions between the host ion and the foreign

cation in the vanadium zirconia pigment is also discussed on the basis of V-O bonds

distances deduced from the Hardcastle and Wach’s equation[32] and of the valence state of

vanadium cation calculated by Brown in the valence sum rule.[35] In Table 2, the bond

distance calculated using Hardcastle and Wach’s equation[32] indicates that the 1.70 Å

value deduced from 991cm-1 frequency is close to 1.76 Å value from X-ray diffraction

for V=O bond in the VO2 compound of the known structure.[37]

Thus, tetravalent chemical state of vanadium in Table 2 calculated by bonds orders

deduced from 991, 701 and 403 cm-1 frequencies with Brown and Wu’s expression[35]

confirm the proposed attribution of 991 cm-1 peak to V4+=O stretching mode.

This suggests that dissolved vanadium ions replace Zr4+ in seven coordinated sites in the

monoclinic zirconia structure.[9] Thus, as the presence of Zr4+ and O2- ions in the V-ZrO2

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


pigment may create an electrostatic field able to perturb the d orbital of the V4+ cation,

this field can then induce a lifting of d orbital degenerated in t2g and eg levels and allow

the d-d electronic transition[38] related to the origin of the lemon yellow coloration.

3. CONCLUSION

Raman results to a certain extent corroborate the X-ray diffraction results suggesting that

the mechanism of the solid solution formation is substitutional. The enhancement of the

relative intensity of developing Raman peak at 991, 701 and 403 cm-1 with the amount of

vanadium doped indicates that these peaks are directly related to bonds involving

vanadium ions. Moreover, by comparison with Raman spectra of vanadium oxides and on

the basis of V-O bonds distances deduced from the Hardcastle and Wach’s equation and

of the valence state of vanadium cation calculated by Brown in the valence sum rule,

these peaks are assigned to be related to V4+=O bonds. This would indicate that doping

would be in occlusion with zirconia net. Inclusion of doping in zirconia net crystalline

should indicate in the Raman spectra the characteristic frequencies of the V2O5

compound.

The V4+ cation allowing the d-d electronic transition is related to the origin of the lemon

yellow coloration.

A deep theoretical analysis of the electronic structure of V-ZrO2 is need to clarify the

active molecular orbital involved in the electronic transition originated of the lemon

yellow coloration.

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


ACKNOWLEDGMENTS

O.E. Kasende would like to thank Professors W. Kiefer and D. de Waal for their

hospitalities at the University of Würzburg, Germany and University of Pretoria, South

Africa, respectively where Raman spectra were recorded. He is grateful to DAAD for the

research visit scholarship at Würzburg and to

ZIUS2009VOA0701/ZIUS2010VOA0701/ZIUS2011VOA0701 VLIR-UOS Program for

financial support for a study visit at the University of Leuven where the last version of

this paper is completed.

REFERENCES

1. Scarff, J.P.; Perrin, P.; Chimie industrielle, 2nd édition, Paris, Dunod, 1999

2. Ren, F.; Ishida, S.; Takeuchi, N. J. Am. Ceram. Soc. 1993, 76, 1825.

3. Weyl, W. A.; Colors oafs Ceramics. In KirK-Othmer Encyclopedia of Chemical

Technology, Vol. 5. The Interscience Encyclopedia: New York, 1964, 845-856.

4. Booth, F. T.; Peel, G. N. Trans. Brit. Ceram. Soc. 1962, 61, 359

5. Monros, G.; Carda, J.; Tena, M. A.; Escribano, P.; Alarcon, J. Trans. Brit. Ceram. Soc.

1991, 90, 157.

6. Fujiki, Y.; Suzuki, Y. J. Cryst. Growth 1974, 24/25, 661.

7. Ishida, S.; Fujimura, Y.; Fujiyoshi, K.; Kanaoka, S. Yogyo Kyokaishi 1983, 91, 546.

8. Tartaj, P.; Serna, C. J.; Soria, J.; Ocana, M. J. Mater. Res. 1998, 13.

9. Alarcon, J. J. Mater. Sci. 2001, 36, 1189.

10. Alyea, E.C.; Bradley, D.C. J. Chem. Soc. A 1969, 16, 2330.

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


11. Michel, D.; Perez, M.; Jorba, Y.; Collongues, R. J. Raman Spectrosc. 1976, 5, 163.

12. Yashima, M.; Ohtake, K.; Kakihana, M.; Arashi, H.; Yoshumura, M. J. Phys. Chem.

Solids 1996, 57, 17.

13. Phillippi, C.D.; Mazdiyansi, K. S. J. Am. Ceram. Soc. 1971, 54, 254.

14. Keramidas, V.G.; White, W.B. J. Am. Ceram. Soc. 1974, 57, 22.

15. Anastassakis, E.; Papanicolaou, B.; Asher, I. M. J. Phys. Chem. Solids 1975, 36, 667.

16. Sohn, J. R.; Han, J.S.; Lim, J.S. Mater. Chem. Phys. 2005, 91, 558.

17. Sohn, J. R.; Han, J.S.; Lim, J.S. J. Ind. Eng. Chem. 2004, 10, 1003.

18. Reddy, B.M.; Lashman, P.; Khan, A. J. Phys. Chem. B 2004, 108, 16855.

19. Scheurell, K.; Hoppe, E.; Brzezinka K.-W.; Kemnitz, E. J. Mater. Chem. 2004, 14,

2560.

20. Sohn, J.R.; Park, J.B.; Kim, H. W.; Pae, Y. Korean J. Chem. Eng. 2003, 20, 48.

21. Sohn, J.R.; Seo, K.C.; Pae, Y. Bull. Korean Chem. Soc. 2003, 24, 311.

22. Sohn, J.R.; Doh, I. J.; Pae, Y. Langmuir. 2002, 18, 6280.

23. Pieck, C.L.; del Val, S.; Lopez Granados, M.; Banares, M.A.; Fierro, J. L. G.

Langmuir 2002, 18, 2642.

24. Pieck, C.L.; Banares, M.A.; Vicente, M.A.; Fierro, J. L. G. Chem. Mater. 2001, 13,

1174.

25. Park, E.H.; Lee, M. H.; Sohn, J.R. Bull. Korean Chem. Soc. 2000, 21, 913.

26. Olthof, B.; Khodakov, Andrei B.; Alexis, T.; Iglesia, E. J. Phys. Chem. B 2000, 104,

1516.

27. Gao, X.; Fierro, J.L.G.; Wachs, I.E. Langmuir 1999, 15, 3169.

28. Sohn, J.R.; Lee, M. H.; Doh, I.J.; Pae, Y. Bull. Korean Chem. Soc. 1998, 19, 856.

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


29. Liu, Z.; Ji, W.; Dong, L.; Chen, Y. Mater. Chem. Phys. 1998, 56, 134.

30. Su, S.C.; Bell, A.T. J. Phys. Chem. B 1998, 102, 7000.

31. Sohn, J.R.; Chu, S.G.; Pae, Y.; Hayashi, S. J. Catal. 1996, 159, 170.

32. Hardcastle, F.D.; Wachs, I.E. J. Phys. Chem. 1991, 95, 5031.

33. de Waal, D.; Heyns, A.M.; Pretorius, G.; Clark, R.J.H. J. Raman Spectrosc. 1996,

27, 657.

34. Brown, I.D.; Shannon, R.D. Acta Crystallogr. 1973, A29, 266.

35. Brown, I.D.; Wu, K.K. Acta Crystallogr. 1976, B32, 1957.

36. Lee, S.; Cheong, H.M.; Seong, M.J.; Liu, P.; Tracy, C.E.; Mascarenhas, A.; Pitts,

J.R.; Deb, S.K. J. Appl. Phys. 2002, 92, 1893.

37. Anderson, G. Acta Chem. Scand. 1956, 10, 623.

38. Caro, P. Structure électronique des éléments de transition dans le cristal, Presses

universitaires de France, 1987.

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


Table 1. Raman Shifts Observed Between 1400-100 cm-1 for VO2, V2O5, Pure Zirconia

and Vanadium-Doped Zirconia Pigment at Various Percentages

VO2 [33] V2O5

[36] VxZr1-xO2

x = 0.0

VxZr1-

xO2 x = 0.01

VxZr1-xO2

x = 0.03

VxZr1-xO2

x = 0.04

VxZr1-xO2

x = 0.05

Assignment

219 (w) 215 (w) 216 (w) 218 (w) 218 (vw) Zirconia

283 281 (m) V-O

266 (w) Zirconia

308 (w) 297 (w) 296 (w) 295 (w) 300 (m) Zirconia

303 V-O

332 (m) 326 (m) 330 (m) 327 (m) 329 (w) Zirconia

342 (vw) 342 (vw) Zirconia

379 (m) 373 (m) 372 (m) 377 (m) 378 (w) Zirconia

405 403 (m) V-O

471 (s) 467 (s) 468 (s) 471 (s) 471 (m) Zirconia

487 V-O

499 (w) 493 (w) 496 (w) 493 (w) 496 (vw) Zirconia

526 530 V-O

532 (w) 528 (w) 530 (w) 524 (w) 524 (m) Zirconia

557 (w) 550 (w) 552 (w) 549 (w) 553 (vw) Zirconia

613 (m) 607 (m) 610 (m) 609 (m) 608 (w) Zirconia

637 (m) 629 (m) 629 (m) 632 (m) 633 (w) Zirconia

692 706 701 (m) V-O

755 (vw) 768 (vw) 768 (vw) Zirconia

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


992 1000 988 (w) 988 (w) 988 (w) 991 (m) V-O

Intensities in parenthesis are abbreviated as vw, very weak; w, weak; m, medium; s,

strong; vs, very strong.

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


Table 2. Raman Stretching Frequency of Vanadium-Oxygen (V-O), V-O Calculated

Bond Distances and Orders Using Hardcastle and Wachs’s Equation and Calculated

Valence State of the Vanadium in the Pigment by Wu’s Empirical Expression.

Compound V-O bond

wavenumbe

r (cm-1)

V-O distances (R) V-O bond

orders (S(V-

O))

calculated

with Brown

and Wu

equation[35]

Valence state

of vanadium

cation (VS)

calculated by

Brown and

Wu

equation[35]

Calculated with

Hardcastle

equation after

de Waal

correction [32] (

Å)

From x-ray

diffraction[37]

( Å)

V-ZrO2 991 1.70 1.76 1.7703 4

701 1.89 1.86 1.0035

403 2.07 - 0.479 (× 2)

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


Figure 1. Raman spectrum of pure zirconia ZrO2 (VxZr1-xO2, with x=0.0)

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT


Figure 2. Raman spectrum of the vanadium-zirconia pigment VxZr1-xO2, with x=0.01

Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

ACCEPTED MANUSCRIPT



Dow

nloa

ded

by [

Dal

hous

ie U

nive

rsity

] at

10:

27 0

1 O

ctob

er 2

013

raman spectrum of vanadium-zirconia yellow pigment

Documents