| This form provides access to NIST critically evaluated data on ground states and ionization energies of atoms and atomic ions. 
 
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  | Spectra:
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 e.g., Fe I
       or Na
       or H-Ds I
       or Mg+
       or Al3+
       or mg iv,vi-VIII; S V-xii
       or Fe ne-like-S-like
       or Ne-Fe I-III
       or Ni-like
       or H-like-Ne-like
 
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  | Units: |  | 
  | Format output: |  | No JavaScript 
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  | Ordered by Z |  | 
  | Ordered by sequence |  | 
  | Output Data: | Atomic number Spectrum name
 Ion charge
 Element name
 Isoelectronic sequence
 
 | Ground-state electronic shells Ground-state configuration
 Ground-state level
 Ionized configuration
 
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  |  | Ionization energy Total binding energy
 Uncertainty
 
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  | Bibliographic references: 
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