WebElements Periodic Table of the Elements | Protactinium

Protactinium: the essentials

Brief description: protactinium has a bright metallic lustre which it retains for some time in air. The element is superconductive below 1.4 K. The element is a dangerous toxic material and requires precautions similar to those used when handling plutonium. Protactinium is one of the rarest and most expensive naturally occurring elements. The element is an α-emitter and is a radiological hazard similar to polonium. Protactinium is a highly toxic and radioactive rare earth metal that requires special handling. It is found in pitchblende and ores form Zaire and is one of the rarest and most expensive naturally occurring elements.

Table: basic information about and classifications of protactinium.
Name: Protactinium Symbol: Pa Atomic number: 91 Atomic weight: 231.03588 (2) Standard state: solid at 298 K CAS Registry ID: 7440-13-3	Group in periodic table: Group name: Actinoid Period in periodic table: 7 (actinoid) Block in periodic table: f-block Colour: silvery metallic Classification: Metallic

protactinium
This sample of uraninite contains some about 10^-6 grammes of actinium at any one time. Image adapted with permission from Prof James Marshall's (U. North Texas, USA) Walking Tour of the elements CD.

Isolation

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Ce	Pr	Nd
Th	Pa	U

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Protactinium
- Essential data: names, symbol, atomic number, and atomic weight; block, period, and group in periodic table; description; standard state; registry number; and isolation
- History: meaning of name; discovery; and history of the element
- Find a property
Protactinium around us
- Uses
- Geology: Abundance of elements in the universe; the sun; meteorites; Earth's crust; oceans; and streams
- Biology: Abundance in humans; biological role; and health hazards)
Protactinium compounds
- Compounds: halides, oxides, sulfides, hydrides, and complexes; lattice energies; and reduction potentials
- Electronegativities: Pauling; Sanderson; Allred Rochow; Mulliken-Jaffe; and Allen
- Bond enthalpies of diatomic species
- Lattice energies
Element properties
- Physics properties: Boiling point; melting point; density; molar volume; thermal conductivity; and electrical resistivity; bulk modulus; critical temperature; superconductivity temperature; hardness (mineralogical, Brinell, and Vickers); linear expansion coefficient; Poisson's ratio; reflectivity; refractive index; rigidity modulus; Young's modulus; velocity of sound
- Images
- Reactions of protactinium: reactions of protactinium with air; water; halogens; acids; and bases
- Crystal structure
- Thermochemistry: enthalpies of atomization, fusion, and vaporization; thermodynamic properties
Atom properties
- Electron shell properties: Electronic configuration; term symbol; electron affinity; ionization energies; and atomic spectra
- Atom sizes: atomic radius; Shannon and Pauling ionic radii; covalent radius; metallic radius; element bond length; and Van der Waals radius
- Atomic orbital properties: effective nuclear charge; electron binding energies; and valence orbital radii maxima
Nuclear properties
- Isotopes: isotope abundances; radioactive isotopes; isotope masses; nuclear spins; and nuclear magnetic moment
- NMR properties: frequencies; isotopes; magnetogyric ratios; quadrupole moments; receptivities; and relative sensitivities

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