William Karnofel

1
Synthesis of Oxides and Pseudo-Oxides

• William Karnofel
• YSU Chemistry 3790
• November 30th, 2005

Chemistry Carried Out at the The Ohio State
University -Department of Chemistry
2
Objectives

• To effectively synthesize oxides and
  pseudo-oxides of solid-state chemistry
• Identify and characterize the synthesized
  compounds
• Measure dielectric and electronic properties of
  the synthesized compounds
• Observe comparisons between a compounds color
  and its electronic properties

3
Background Information

• BiFeO3
• Exhibits ferroelectric, ferroelastic,
  antiferromagnetic, piezoelectric, and dielectric
  properties
• Cuprate perovskites
• Pigmentation
• Metal tungstates
• Exhibits ferroelectric, piezoelectric, and
  dielectric properties
• Uses for scintillators

4
Background Information

• TiNF
• Possible dielectric properties
• Precursor to oxide analogs
• Pigmentation
• Novel Oxynitrides
• Possibly exhibit photo catalytic and/or magnetic
  and/or dielectric properties

5
BiFeO3

• Preparation
• Bi2O3 Fe2O3 ? 2BiFeO3
• Synthesis occurred at 750C for 3 hours in air
• 100 excess Bi2O3 to prevent formation of
  by-product Bi2Fe4O9
• After sintering, the product is quenched to
  prevent formation of Bi2Fe4O9
• The product is washed in concentrated HNO3 to rid
  unreacted Bi2O3 for no longer than six minutes or
  formation of Bi2Fe4O9 occurs

6
BiFeO3
Calculated band gap is 1.7 eV
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Cuprate Perovskites

• Preparation
• A2CO3 CuO BOx ? A2CuBO6
• (A Ba, Sr B Te, W x 2,3)
• Synthesis of A2CuWO6 occurred at 900C for 12
  hours then 1000C for 24 hours in air
• Synthesis of A2CuTeO6 occurred at 900C for 12
  hours then 1100C for 24 hours in air
• Synthesis of Sr2CuWO6 must be quenched after
  sintering to prevent the impurity Sr2WO4

8
Cuprate Perovskites
Calculated band gaps Sr2CuWO6 2.2 eV Sr2CuTeO6
2.4 eV Ba2CuWO6 2.1 eV Ba2CuTeO6 2.0 eV
Sr2CuWO6
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Ternary Metal Tungstates

• Preparation
• AO WO3 ? AWO4 or
• BxCO3 WO3 ? BxWO4
• (A Pb, Ba B Pb, Ba, Na x 1,2)
• Synthesis of AWO4 occurred at 1100C for five
  hours in air
• Synthesis of Na2WO4 occurred at 600C for five
  hours in air

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Ternary Metal Tungstates
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Ternary Metal Tungstates
BaWO4
Calculated band gaps PbWO4 3.6 eV BaWO4 4.0
eV Na2WO4 4.6 eV
12
TiNF

• Preparation
• (NH4)2TiF6 NH4Cl ? TiNF
• Appropriate masses were mixed together then added
  to a beaker with 10 mL of acetone added
• Heated under flowing argon at 215C for 24 hours
  and then at 260C for 12 hours
• Heated under flowing ammonia at 340C for 96
  hours then heated additional 24 hours if needed

13
TiNF
Calculated band gaps Green TiNF 2.8 eV Yellow
TiNF 2.3 eV
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Attempted Novel Oxynitrides

• Preparation
• ACO3 B2O3 ? ABOxNy
• (A Ba, Mg B La, Sc)
• Heated under flowing ammonia at 900C for 10
  hours
• These are novel compounds so it is not known if x
  and y would equal one
• For the attempted BaLaON synthesis, metal oxides
  resulted
• For the attempted MgScON trial, a pink,
  air-sensitive compound resulted

15
Future Work

• BiFeO3 and Cuprate Perovskites
• Magnetic and dielectric characterizations
• Ternary Metal Tungstates
• Dielectric and piezoelectric characterizations
• TiNF
• Dielectric characterizations
• Precursor to other mixed anion compounds
• Novel Oxynitrides
• Identification and characterization of the pink,
  air-sensitive compound during the MgScON trial
• Attempt other novel oxynitrides

16
References

• G. D. Achenbach, W. J. James, R. Gerson, J. Am.
  Chem. Soc. 50, 437 (1967).
• D. Iwanaga, Y. Inaguma, M. Itoh, J. Solid State
  Chem. 147, 291 (1999).
• Kroger, F. A. Some Aspects of the Luminescence
  of Solids. New York Elsevier Pub. Co. Inc.,
  1948. 107-157
• C. Wuestefeld, T. Vogt, U. Loechner, J. Straehle,
  H. Fuess, Angewandte Chemie. 100, 1013 (1988).
• J. Wang, J. B. Neaton, H. Zheng, et al, Science.
  299, 1719 (2003).

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Acknowledgements

• Dr. Pat Woodward
• Rebecca Ricciardo
• Harry Seibel
• Matt Stoltzfus
• Young-Il Kim
• Shawn Walsh
• National Science Foundation
• The Ohio State University