Ionic Radii

pyrolite incldues a few sets of reference tables for ionic radii in aangstroms (Å) from [Shannon1976] and [WhittakerMuntus1970], each with tables indexed by element, ionic charge and coordination. The easiset way to access these is via the get_ionic_radii() function. The function can be used to get radii for individual elements, using a source keyword argument to swap between the datasets:

import matplotlib.pyplot as plt
import pandas as pd

from pyrolite.geochem.ind import REE, get_ionic_radii

REE_radii = pd.Series(
    get_ionic_radii(REE(), coordination=8, charge=3, source="Whittaker"), index=REE()
)
REE_radii

La    1.26
Ce    1.22
Pr    1.22
Nd    1.20
Sm    1.17
Eu    1.15
Gd    1.14
Tb    1.12
Dy    1.11
Ho    1.10
Er    1.08
Tm    1.07
Yb    1.06
Lu    1.05
dtype: float64

REE_radii.pyroplot.spider(color="k", logy=False)
plt.show()

References

Shannon1976: Shannon RD (1976). Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallographica Section A 32:751–767. doi: 10.1107/S0567739476001551.
WhittakerMuntus1970: Whittaker, E.J.W., Muntus, R., 1970. Ionic radii for use in geochemistry. Geochimica et Cosmochimica Acta 34, 945–956. doi: 10.1016/0016-7037(70)90077-3.
Pauling1960: Pauling, L., 1960. The Nature of the Chemical Bond. Cornell University Press, Ithaca, NY.