Data
Elements
The followig data are currently available:
| Name |
Type |
Comment |
Unit |
Data Source |
|---|
| abundance_crust |
float |
Abundance in the Earth’s crust |
mg/kg |
[haynes2014crc] |
| abundance_sea |
float |
Abundance in the seas |
mg/L |
[haynes2014crc] |
| annotation |
str |
Annotations regarding the data |
|
|
| atomic_number |
int |
Atomic number |
|
|
| atomic_radius |
float |
Atomic radius |
pm |
[Slater1964] |
| atomic_radius_rahm |
float |
Atomic radius by Rahm et al. |
pm |
[Rahm2016][Rahm2017] |
| atomic_volume |
float |
Atomic volume |
cm3/mol |
|
| atomic_weight |
float |
Atomic weight |
|
[Meija2016][iupac-weights] |
| atomic_weight_uncertainty |
float |
Atomic weight uncertainty |
|
[Meija2016][iupac-weights] |
| block |
str |
Block in periodic table |
|
|
| boiling_point |
float |
Boiling temperature |
K |
|
| c6 |
float |
C_6 dispersion coefficient in a.u. |
a.u. |
[Chu2004][Tang1976] |
| c6_gb |
float |
C_6 dispersion coefficient in a.u. (Gould & Bučko) |
a.u. |
[Gould2016] |
| cas |
str |
Chemical Abstracts Serice identifier |
|
|
| covalent_radius_bragg |
float |
Covalent radius by Bragg |
pm |
[Bragg1920] |
| covalent_radius_cordero |
float |
Covalent radius by Cerdero et al. |
pm |
[Cordero2008] |
| covalent_radius_pyykko |
float |
Single bond covalent radius by Pyykko et al. |
pm |
[Pyykko2009] |
| covalent_radius_pyykko_double |
float |
Double bond covalent radius by Pyykko et al. |
pm |
[Pyykko2009a] |
| covalent_radius_pyykko_triple |
float |
Triple bond covalent radius by Pyykko et al. |
pm |
[Pyykko2005] |
| cpk_color |
str |
Element color in CPK convention |
HEX |
[wiki-cpk] |
| density |
float |
Density at 295K |
g/cm3 |
|
| description |
str |
Short description of the element |
|
|
| dipole_polarizability |
float |
Dipole polarizability |
a.u. |
[Schwerdtfeger2018] |
| dipole_polarizability_unc |
float |
Dipole polarizability uncertainty |
a.u. |
[Schwerdtfeger2018] |
| discoverers |
str |
The discoverers of the element |
|
|
| discovery_location |
str |
The location where the element was discovered |
|
|
| dipole_year |
int |
The year the element was discovered |
|
|
| electron_affinity |
float |
Electron affinity |
eV |
[haynes2014crc][Andersen2004] |
| electrons |
int |
Number of electrons |
|
|
| en_allen |
float |
Allen’s scale of electronegativity |
eV |
[Mann2000a][Mann2000] |
| en_ghosh |
float |
Ghosh’s scale of electronegativity |
|
[Ghosh2005] |
| en_mulliken |
float |
Mulliken’s scale of electronegativity |
eV |
[Mulliken1934] |
| en_pauling |
float |
Pauling’s scale of electronegativity |
|
[haynes2014crc] |
| econf |
str |
Ground state electron configuration |
|
|
| evaporation_heat |
float |
Evaporation heat |
kJ/mol |
|
| fusion_heat |
float |
Fusion heat |
kJ/mol |
|
| gas_basicity |
float |
Gas basicity |
kJ/mol |
[haynes2014crc] |
| geochemical_class |
str |
Geochemical classification |
|
[white2013geochemistry] |
| glawe_number |
int |
Glawe’s number (scale) |
|
[Glawe2016] |
| goldschmidt_class |
str |
Goldschmidt classification |
|
[white2013geochemistry][wiki-goldschmidt] |
| group |
int |
Group in periodic table |
|
|
| heat_of_formation |
float |
Heat of formation |
kJ/mol |
[haynes2014crc] |
| ionenergy |
tuple |
Ionization energies |
eV |
[NIST-ASD] |
| ionic_radii |
list |
Ionic and crystal radii in pm |
pm |
[Shannon1976] |
| is_monoisotopic |
bool |
Is the element monoisotopic |
|
|
| is_radioactive |
bool |
Is the element radioactive |
|
|
| isotopes |
list |
Isotopes |
|
|
| jmol_color |
str |
Element color in Jmol convention |
HEX |
[jmol-colors] |
| lattice_constant |
float |
Lattice constant |
Angstrom |
|
| lattice_structure |
str |
Lattice structure code |
|
|
| mass_number |
int |
Mass number (most abundant isotope) |
|
|
| melting_point |
float |
Melting temperature |
K |
|
| mendeleev_number |
int |
Mendeleev’s number |
|
[Pettifor1984][Villars2004] |
| metallic_radius |
float |
Single-bond metallic radius |
pm |
[kyleandlaby] |
| metallic_radius_c12 |
float |
Metallic radius with 12 nearest neighbors |
pm |
[kyleandlaby] |
| molcas_gv_color |
str |
Element color in MOCAS GV convention |
HEX |
[molcas-colors] |
| name |
str |
Name in English |
|
|
| name_origin |
str |
Origin of the name |
|
|
| neutrons |
int |
Number of neutrons (most abundant isotope) |
|
|
| oxistates |
list |
Oxidation states |
|
|
| period |
int |
Period in periodic table |
|
|
| pettifor_number |
float |
Pettifor scale |
|
[Pettifor1984] |
| proton_affinity |
float |
Proton affinity |
kJ/mol |
[haynes2014crc] |
| protons |
int |
Number of protons |
|
|
| sconst |
float |
Nuclear charge screening constants |
|
[Clementi1963][Clementi1967] |
| series |
int |
Index to chemical series |
|
|
| sources |
str |
Sources of the element |
|
|
| specific_heat |
float |
Specific heat @ 20 C |
J/(g mol) |
|
| symbol |
str |
Chemical symbol |
|
|
| thermal_conductivity |
float |
Thermal conductivity @25 C |
W/(m K) |
|
| uses |
str |
Applications of the element |
|
|
| vdw_radius |
float |
Van der Waals radius |
pm |
[haynes2014crc] |
| vdw_radius_alvarez |
float |
Van der Waals radius according to Alvarez |
pm |
[Alvarez2013][Vogt2014] |
| vdw_radius_batsanov |
float |
Van der Waals radius according to Batsanov |
pm |
[Batsanov2001] |
| vdw_radius_bondi |
float |
Van der Waals radius according to Bondi |
pm |
[Bondi1964] |
| vdw_radius_dreiding |
float |
Van der Waals radius from the DREIDING FF |
pm |
[Mayo1990] |
| vdw_radius_mm3 |
float |
Van der Waals radius from the MM3 FF |
pm |
[Allinger1994] |
| vdw_radius_rt |
float |
Van der Waals radius according to Rowland and Taylor |
pm |
[Rowland1996] |
| vdw_radius_truhlar |
float |
Van der Waals radius according to Truhlar |
pm |
[Mantina2009] |
| vdw_radius_uff |
float |
Van der Waals radius from the UFF |
pm |
[Rappe1992] |
Isotopes
| Name |
Type |
Comment |
Unit |
Data Source |
|---|
| abundance |
float |
Relative Abundance |
|
[iupac-abund] |
| g_factor |
float |
Nuclear g-factor |
|
[Stone2014] |
| half_life |
float |
Half life of the isotope |
|
[Meija2016] |
| half_life_unit |
str |
Unit in which the half life is given |
|
[Meija2016] |
| is_radioactive |
bool |
Is the isotope radioactive |
|
[iupac-masses] |
| mass |
float |
Atomic mass |
Da |
[iupac-masses] |
| mass_number |
int |
Mass number of the isotope |
|
[iupac-masses] |
| mass_uncertainty |
float |
Uncertainty of the atomic mass |
|
[iupac-masses] |
| spin |
float |
Nuclear spin quantum number |
|
|
| quadrupole_moment |
float |
Nuclear electric quadrupole moment |
b [100 fm^2] |
[Stone2013] |
Data Footnotes
| [1] | (1, 2) Atomic Weights
Atomic weights and their uncertainties were retrieved mainly from ref. [iupac-weights]. For
elements whose values were given as ranges the conventional atomic weights from
Table 3 in ref. [Meija2016] were taken. For radioactive elements the standard approach
was adopted where the weight is taken as the mass number of the most stable isotope.
The data was obtained from CIAAW page on radioactive elements.
In cases where two isotopes were specified the one with the smaller standard deviation was chosen.
In case of Tc and Pm relative weights of their isotopes were used, for Tc isotope 98, and for Pm isotope 145 were taken
from CIAAW.
|
| [2] | Covalent Radius by Cordero et al.
In order to have a more homogeneous data for covalent radii taken from ref.
[Cordero2008] the values for 3 different valences for C, also the low
and high spin values for Mn, Fe Co, were respectively averaged.
|
| [3] | Electron affinity
Electron affinities were taken from [haynes2014crc] for the elements
for which the data was available. For He, Be, N, Ar and Xe affinities were
taken from [Andersen2004] where they were specified for metastable
ions and therefore the values are negative.
Updates
- Electron affinity of niobium was taken from [Luo2016].
- Electron affinity of cobalt was taken from [Chen2016a].
- Electron affinity of lead was taken from [Chen2016].
|
| [4] | Allen’s configuration energies
The values of configurational energies from refs. [Mann2000a] and
[Mann2000] were taken as reported in eV without converting to Pauling
units.
|
| [5] | Mendeleev numbers
Mendeleev numbers were mostly taken from [Villars2004] but the range
was extended to cover the whole periodic table following the prescription
in the article of increasing the numbers going from top to bottom in each
group and group by group from left to right in the periodic table.
|
| [6] | Nuclear charge screening constants
The screening constants were calculated according to the following formula
\[\sigma_{n,l,m} = Z - n\cdot\zeta_{n,l,m}\]
where \(n\) is the principal quantum number, \(Z\) is the atomic number,
\(\sigma_{n,l,m}\) is the screening constant, \(\zeta_{n,l,m}\) is the
optimized exponent from [Clementi1963][Clementi1967].
For elements Nb, Mo, Ru, Rh, Pd and Ag the exponent values corresponding to the
ground state electronic configuration were taken (entries with superscript a
in Table II in [Clementi1967]).
For elements La, Pr, Nd and Pm two exponent were reported for 4f shell denoted
4f and 4f’ in [Clementi1967]. The value corresponding to 4f were used
since according to the authors these are the dominant ones.
|
| [7] | van der Waals radii according to Alvarez
The bulk of the radii data was taken from Ref. [Alvarez2013], but the
radii for noble gasses were update according to the values in Ref.
[Vogt2014].
|
| [8] | (1, 2) Isotope g-factors and quadrupole moments
The data regarding g-factors and electric quadrupole moments was parsed from
easyspin webpage
(accessed 25.01.2017) where additional notes are mentioned:
- Typo for Rh-103: Moment is factor of 10 too large
- 237Np, 239Pu, 243Am magnetic moment data from [haynes2014crc], section 11-2
- In quadrupole moment data - a typo for Ac-227: sign should be +
|
Electronegativities
Since electronegativity is useful concept rather than a physical observable,
several scales of electronegativity exist and some of them are available in
mendeleev. Depending on the definition of a particular
scale the values are either stored directly or recomputed on demand with
appropriate formulas. The following scales are stored:
Moreover there are electronegativity scales that can be computed from their
respective definition and the atomic properties available in mendeleev:
For a short overview on electronegativity see this presentation.
All the examples shown below are for Silicon:
>>> from mendeleev import element
>>> Si = element('Si')
Allen
The electronegativity scale proposed by Allen in ref [Allen1989] can be defined as:
\[\chi_{A} = \frac{\sum_{x} n_{x}\varepsilon_{x}}{\sum_{x}n_{x}}\]
where: \(\varepsilon_{x}\) is the multiplet-averaged one-electron energy of
the subshell \(x\) and \(n_{x}\) is the number of electrons in subshell
\(x\) and the summation runs over the valence shell.
The values that are tabulated were obtained from refs. [Mann2000a] and [Mann2000].
Example:
>>> Si.en_allen
11.33
>>> Si.electronegativity('allen')
11.33
Allred and Rochow
The scale of Allred and Rochow [Allred1958] introduces the electronegativity as the
electrostatic force exerted on the electron by the nuclear charge:
\[\chi_{AR} = \frac{e^{2}Z_{\text{eff}}}{r^{2}} \notag\]
where: \(Z_{\text{eff}}\) is the effective nuclear charge and \(r\) is
the covalent radius.
Example:
>>> Si.electronegativity('allred-rochow')
0.00028240190249702736
Cottrell and Sutton
The scale proposed by Cottrell and Sutton [Cottrell1951] is derived from the equation:
\[\chi_{CS} = \sqrt{\frac{Z_{\text{eff}}}{r}}\]
where: \(Z_{\text{eff}}\) is the effective nuclear charge and \(r\) is
the covalent radius.
Example:
>>> Si.electronegativity('cottrell-sutton')
0.18099342720014772
Ghosh
Ghosh [Ghosh2005] presented a scale of electronegativity based on the absolute radii of atoms computed as
\[\chi_{GH} = a \cdot (1/R) + b\]
where: \(R\) is the absolute atomic radius and \(a\) and \(b\) are
empirical parameters.
Example:
Gordy
Gordy’s scale [Gordy1946] is based on the potential that measures the work necessary
to achieve the charge separation, according to:
\[\chi_{G} = \frac{eZ_{\text{eff}}}{r}\]
where: \(Z_{\text{eff}}\) is the effective nuclear charge and \(r\) is
the covalent radius.
Example:
>>> Si.electronegativity('gordy')
0.03275862068965517
Li and Xue
Li and Xue [Li2006][Li2009] proposed a scale that takes into account
different valence states and coordination environment of atoms and is
calculated according to the following formula:
\[\chi_{LX} = \frac{n^{*}\sqrt{I_{j}/Ry}}{r}\]
where: \(n^{*}\) is the effective principal quantum number, \(I_{j}\)
is the j’th ionization energy in eV, \(Ry\) is the Rydberg constant in
eV and \(r\) is either the crystal radius or ionic radius.
Example:
>>> Si.en_li_xue(charge=4)
{u'IV': 13.16033405547733, u'VI': 9.748395596649873}
>>> Si.electronegativity('li-xue', charge=4)
{u'IV': 13.16033405547733, u'VI': 9.748395596649873}
Martynov and Batsanov
Martynov and Batsanov [Batsanov1982] used the square root of the
averaged valence ionization energy as a measure of electronegativity:
\[\chi_{MB} = \sqrt{\frac{1}{n_{v}}\sum^{n_{v}}_{k=1} I_{k}}\]
where: \(n_{v}\) is the number of valence electrons and \(I_{k}\)
is the \(k\) th ionization potential.
Example:
>>> Si.en_martynov_batsanov()
5.0777041564076963
>>> Si.electronegativity(scale='martynov-batsanov')
5.0777041564076963
Mulliken
Mulliken scale [Mulliken1934] is defined as the arithmetic average of the ionization
potential (\(IP\)) and the electron affinity (\(EA\)):
\[\chi_{M} = \frac{IP + EA}{2}\]
Example:
>>> Si.en_mulliken()
4.0758415
>>> Si.electronegativity('mulliken')
4.0758415
Nagle
Nagle [Nagle1990] derived his scale from the atomic dipole polarizability:
\[\chi_{N} = \sqrt[3]{\frac{n}{\alpha}} \notag\]
Example:
>>> Si.electronegativity('nagle')
0.47505611644667534
Pauling
Pauling’s thermochemical scale was introduced in [Pauling1932] as a relative scale based
on electronegativity differences:
\[\chi_{A} - \chi_{B} = \sqrt{E_{d}(AB) - \frac{1}{2}\left[E_{d}(AA) + E_{d}(BB)\right] }\]
where: \(E_{d}(XY)\) is the bond dissociation energy of a diatomic \(XY\).
The values available in mendeleev are taken from ref. [haynes2014crc].
Example:
>>> Si.en_pauling
1.9
>>> Si.electronegativity('pauling')
1.9
Sanderson
Sanderson [Sanderson1951][Sanderson1952] established his scale of electronegativity based on the
stability ratio:
\[\chi_{S} = \frac{\rho}{\rho_{\text{ng}}}\]
where: \(\rho\) is the average electron density \(\rho=\frac{Z}{4\pi r^{3}/3}\),
and \(\rho_{\text{ng}}\) is the average electron density of a hypothetical
noble gas atom with charge \(Z\).
Example:
>>> Si.en_sanderson()
0.3468157872145231
>>> Si.electronegativity()
0.3468157872145231
Bibliography
| [2] | Leland C Allen. Electronegativity is the average one-electron energy of the valence-shell electrons in ground-state free atoms. Journal of the American Chemical Society, 111(25):9003–9014, 1989. doi:10.1021/ja00207a003. |
| [5] | (1, 2) Santiago Alvarez. A cartography of the van der Waals territories. Dalton Transactions, 42(24):8617, 2013. doi:10.1039/c3dt50599e. |
| [16] | (1, 2) Beatriz Cordero, Verónica Gómez, Ana E Platero-Prats, Marc Revés, Jorge Echeverría, Eduard Cremades, Flavia Barragán, and Santiago Alvarez. Covalent radii revisited. Dalton Transactions, pages 2832, 2008. URL: http://xlink.rsc.org/?DOI=b801115j, doi:10.1039/b801115j. |
| [22] | (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11) William M Haynes. CRC Handbook of Chemistry and Physics. 100 Key Points. CRC Press, London, 95th edition, 2014. ISBN 9781482208689. URL: https://books.google.no/books?id=bNDMBQAAQBAJ. |
| [23] | A Kramida, Yu Ralchenko, J Reader, and and NIST ASD Team. Nist atomic spectra database (ver. 5.3), national institute of standards and technology, gaithersburg, md. 2015. [Online; accessed 13-April-2015]. URL: http://physics.nist.gov/asd. |
| [31] | (1, 2, 3, 4, 5) Juris Meija, Tyler B. Coplen, Michael Berglund, Willi A. Brand, Paul De Bièvre, Manfred Gröning, Norman E. Holden, Johanna Irrgeher, Robert D. Loss, Thomas Walczyk, and Thomas Prohaska. Atomic weights of the elements 2013 (IUPAC Technical Report). Pure and Applied Chemistry, 88(3):265–291, jan 2016. URL: http://www.degruyter.com/view/j/pac.2016.88.issue-3/pac-2015-0305/pac-2015-0305.xml, doi:10.1515/pac-2015-0305. |
| [42] | R Scott Rowland and Robin Taylor. Intermolecular Nonbonded Contact Distances in Organic Crystal Structures: Comparison with Distances Expected from van der Waals Radii. The Journal of Physical Chemistry, 100(18):7384–7391, 1996. doi:10.1021/jp953141+. |
| [46] | R. D. Shannon. Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallographica Section A, 32(5):751–767, 1976. doi:10.1107/S0567739476001551. |