\(\renewcommand\AA{\text{Å}}\)
Density¶
periodictable.density
¶
The following properties are added:
 density, density_units (g·cm^{3})
 Densities for solids and liquids are given as specific gravities at 20° C unless other wise indicated by density_caveat. Densities for gaseous elements are given for the liquids at their boiling points. Missing data are represented by None.
 density_caveat
 Comments on the density, if not taken in standard conditions.
 interatomic_distance, interatomic_distance_units (Å)
 Interatomic distance estimated from element density.
 number_density, number_density_units (cm^{3})
 Number density estimated from mass and density.
Density for the isotope is computed assuming that the atomic spacing is the same as that for the element in the natural abundance.
>>> from periodictable import D, H
>>> print("H: %.4f, D: %.4f"%(H.density, D.density))
H: 0.0708, D: 0.1415
>>> print((D.density/H.density) / (D.mass/H.mass))
1.0
The following plot shows density for all elements:
(Source code, png, hires.png, pdf)
From the Xray data book: http://xdb.lbl.gov/Section5/Sec_52.html
Data were taken mostly from [1]. These values are reproduced in [2].
[1]  Lide. D. R., Ed., CRC Handbook of Chemistry and Physics, 80th ed. (CRC Press, Boca Raton, Florida, 1999) 
[2]  The ILL Neutron Data Booklet, Second Edition. 

periodictable.density.
density
(iso_el)¶ Element density for natural abundance. For isotopes, return the equivalent density assuming identical interatomic spacing as the naturally occuring material.
Parameters:  iso_el : isotope or element
Name of the element or isotope.
Returns: density : float  g·cm^{3}
 Reference:
 ILL Neutron Data Booklet, original values from CRC Handbook of Chemistry and Physics, 80th ed. (1999).

periodictable.density.
init
(table, reload=False)¶

periodictable.density.
interatomic_distance
(element)¶ Estimated interatomic distance from atomic weight and density. The distance between isotopes is assumed to match that between atoms in the natural abundance.
Parameters:  element : Element
The element whose interatomic distance is to be calculated.
Returns:  distance : float  Å
Estimated interatomic distance.
Interatomic distance is computed using:
\[d = (m/(\rho_m N_A 10^{24}))^{1/3}\]with units:
\[(\rm (g\cdot mol^{1}) / ( (g\cdot cm^{3}) (atoms\cdot mol^{1}) (10^{8} cm\cdot \AA^{1})^3))^{1/3} = \AA\]

periodictable.density.
number_density
(element)¶ Estimate the number density from atomic weight and density. The density for isotopes is assumed to match that of between atoms in natural abundance.
Parameters:  element : element
Name of the element whose number density needs to be calculated.
Returns:  Nb : float  cm^{3}
Number density of a element.
Number density is computed using:
\[d = N_A \frac{\rho}{m}\]with units:
\[\rm (atoms\cdot mol^{1}) (g\cdot cm^{3}) / (g\cdot mol^{1}) = atoms\cdot cm^{3}\]