Tantalum • Transition Metal
Primary XPS region: Ta4f
Overlapping regions: O2s
Binding energies of common chemical states:
|Chemical state||Binding energy Ta4f7/2|
|Ta metal||21.8 eV|
- Ta4f region has well separated spin-orbit components (Δmetal=1.92eV).
- Loss feature for Ta metal appears at ~33eV and ~38eV for Ta2O5.
- Peaks in the Ta4f region have an asymmetric peak shape for tantalum metal.
- Tantalum compounds, such as the oxide, have symmetric Ta4f peaks.
- Use Smart background when sputter profiling films such as Ta2O5 on Ta or TaN on Ta.
- Linear or Shirley background which is suitable forTa2O5 or TaN will not be suitable for Ta metal.
- Tantalum oxide is widely used as a depth profiling sputter calibration standard because it can be grown with a controlled thickness by electrochemical methods.
- Tantalum oxide is reduced by an argon ion beam to form a continuum of oxidation states e.g. Ta2O5, Ta3O7, Ta4O9, etc.
- Use lowest beam energy possible for depth profiling or gas cluster ion source to clean (if available).
Date of discovery: 1802
Name origin: King Tantalus (Greek mythology)
Discoverer: Anders Ekeberg
Obtained from: columbite-tantalite
Melting point: 3290 K
Boiling point: 5731 K
Molar volume: 10.85 × 10-6 m3/mol
Shell structure: 2,8,18,32,11,2
Electron configuration: [Xe]4f145d36s2
Oxidation state: 5,4,3
Crystal structure: cubic
This high-melting point transition metal was separated from niobium in 1802 by A. Ekeberg. When pure, tantalum can be drawn into a fine wire for use as a filament for evaporating metals. Due to its high melting point, ductility, and corrosion resistance, tantalum is often incorporated into a variety of metal alloys for use in chemical process equipment, capacitors and aircraft parts. The metal alloy tantalum carbide graphite is one of the hardest metals known, with a melting point of 3738°C. Tantalum is a non-irritating metal and is immune to body liquids, making it well-suited for use in surgical applications.
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