.. _data: **** Data **** To find out how to fetch data in bulk, check out the documentation about :doc:`data access `. Elements ======== The following data are currently available: +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | Name | Type | Comment | Unit | Data Source | +===============================+=======+======================================================+===================+=====================================================+ | abundance_crust | float | Abundance in the Earth's crust | mg/kg | :cite:`haynes2014crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | abundance_sea | float | Abundance in the seas | mg/L | :cite:`haynes2014crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | annotation | str | Annotations regarding the data | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | atomic_number | int | Atomic number | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | atomic_radius | float | Atomic radius | pm | :cite:`Slater1964` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | atomic_radius_rahm | float | Atomic radius by Rahm et al. | pm | :cite:`Rahm2016,Rahm2017` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | atomic_volume | float | Atomic volume | cm\ :sup:`3`/mol | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | atomic_weight | float | Atomic weight\ ([#f1]_) | | :cite:`Meija2016,iupac-weights` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | atomic_weight_uncertainty | float | Atomic weight uncertainty\ ([#f1]_) | | :cite:`Meija2016,iupac-weights` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | block | str | Block in periodic table | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | boiling_point | float | Boiling temperature | K | :cite:`haynes2016crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | c6 | float | C_6 dispersion coefficient in a.u. | a.u. | :cite:`Chu2004,Tang1976` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | c6_gb | float | C_6 dispersion coefficient in a.u. (Gould & Bučko) | a.u. | :cite:`Gould2016` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | cas | str | Chemical Abstracts Serice identifier | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | covalent_radius_bragg | float | Covalent radius by Bragg | pm | :cite:`Bragg1920` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | covalent_radius_cordero | float | Covalent radius by Cerdero et al.\ ([#f2]_) | pm | :cite:`Cordero2008` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | covalent_radius_pyykko | float | Single bond covalent radius by Pyykko et al. | pm | :cite:`Pyykko2009` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | covalent_radius_pyykko_double | float | Double bond covalent radius by Pyykko et al. | pm | :cite:`Pyykko2009a` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | covalent_radius_pyykko_triple | float | Triple bond covalent radius by Pyykko et al. | pm | :cite:`Pyykko2005` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | cpk_color | str | Element color in CPK convention | HEX | :cite:`wiki-cpk` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | critical_pressure | float | Critical pressure | MPa | :cite:`haynes2016crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | critical_temperature | float | Critical temperature | K | :cite:`haynes2016crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | density | float | Density at 295K\ ([#f10]_) | g/cm\ :sup:`3` | :cite:`haynes2014crc,enwiki:1039678864` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | description | str | Short description of the element | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | dipole_polarizability | float | Dipole polarizability | a.u. | :cite:`Schwerdtfeger2018` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | dipole_polarizability_unc | float | Dipole polarizability uncertainty | a.u. | :cite:`Schwerdtfeger2018` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | discoverers | str | The discoverers of the element | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | discovery_location | str | The location where the element was discovered | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | discovery_year | int | The year the element was discovered | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | electron_affinity | float | Electron affinity\ ([#f3]_) | eV | :cite:`haynes2014crc,Andersen2004` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | electrons | int | Number of electrons | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | electrophilicity | float | Electrophilicity index | eV | :cite:`Parr1999` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | en_allen | float | Allen's scale of electronegativity\ ([#f4]_) | eV | :cite:`Mann2000a,Mann2000` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | en_ghosh | float | Ghosh's scale of electronegativity | | :cite:`Ghosh2005` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | en_mulliken | float | Mulliken's scale of electronegativity | eV | :cite:`Mulliken1934` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | en_pauling | float | Pauling's scale of electronegativity | | :cite:`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 | :cite:`haynes2014crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | geochemical_class | str | Geochemical classification | | :cite:`white2013geochemistry` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | glawe_number | int | Glawe's number (scale) | | :cite:`Glawe2016` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | goldschmidt_class | str | Goldschmidt classification | | :cite:`white2013geochemistry,wiki-goldschmidt` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | group | int | Group in periodic table | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | heat_of_formation | float | Heat of formation | kJ/mol | :cite:`haynes2014crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | inchi | str | International Chemical Identifier | | :cite:`IUPAC-InChI` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | ionenergy | tuple | Ionization energies | eV | :cite:`NIST-ASD` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | ionic_radii | list | Ionic and crystal radii in pm\ ([#f9]_) | pm | :cite:`Shannon1976,Lundberg2016` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | 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 | :cite:`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 | :cite:`haynes2016crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | mendeleev_number | int | Mendeleev's number\ ([#f5]_) | | :cite:`Pettifor1984,Villars2004` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | metallic_radius | float | Single-bond metallic radius | pm | :cite:`kyleandlaby` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | metallic_radius_c12 | float | Metallic radius with 12 nearest neighbors | pm | :cite:`kyleandlaby` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | molar_heat_capacity | float | Molar heat capacity @ 25 C, 1 bar | J/(mol K) | :cite:`haynes2014crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | molcas_gv_color | str | Element color in MOCAS GV convention | HEX | :cite:`molcas-colors` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | name | str | Name in English | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | name_origin | str | Origin of the name | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | neutrons | int | Number of neutrons (most abundant isotope) | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | oxistates | list | Commonly occurring oxidation states | | :cite:`enwiki:1102394064` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | nist_webbook_url | str | URL for the NIST Chemistry WebBook | | :cite:`NIST-CH-WB` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | oxistates | list | Oxidation states | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | period | int | Period in periodic table | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | pettifor_number | float | Pettifor scale | | :cite:`Pettifor1984` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | proton_affinity | float | Proton affinity | kJ/mol | :cite:`haynes2014crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | protons | int | Number of protons | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | sconst | float | Nuclear charge screening constants\ ([#f6]_) | | :cite:`Clementi1963,Clementi1967` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | series | int | Index to chemical series | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | sources | str | Sources of the element | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | specific_heat_capacity | float | Specific heat capacity @ 25 C, 1 bar | J/(g K) | :cite:`haynes2014crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | symbol | str | Chemical symbol | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | thermal_conductivity | float | Thermal conductivity @25 C | W/(m K) | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | triple_point_pressure | float | Triple point pressure | kPa | :cite:`haynes2016crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | triple_point_temperature | float | Triple point temperature | K | :cite:`haynes2016crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | uses | str | Applications of the element | | | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | vdw_radius | float | Van der Waals radius | pm | :cite:`haynes2014crc` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | vdw_radius_alvarez | float | Van der Waals radius according to Alvarez\ ([#f7]_) | pm | :cite:`Alvarez2013,Vogt2014` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | vdw_radius_batsanov | float | Van der Waals radius according to Batsanov | pm | :cite:`Batsanov2001` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | vdw_radius_bondi | float | Van der Waals radius according to Bondi | pm | :cite:`Bondi1964` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | vdw_radius_dreiding | float | Van der Waals radius from the DREIDING FF | pm | :cite:`Mayo1990` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | vdw_radius_mm3 | float | Van der Waals radius from the MM3 FF | pm | :cite:`Allinger1994` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | vdw_radius_rt | float | Van der Waals radius according to Rowland and Taylor | pm | :cite:`Rowland1996` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | vdw_radius_truhlar | float | Van der Waals radius according to Truhlar | pm | :cite:`Mantina2009` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ | vdw_radius_uff | float | Van der Waals radius from the UFF | pm | :cite:`Rappe1992` | +-------------------------------+-------+------------------------------------------------------+-------------------+-----------------------------------------------------+ Isotopes ======== +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | Name | Type | Comment | Unit | Data Source | +===============================+=======+======================================================+======================+=========================+ | abundance | float | Relative Abundance | | :cite:`Kondev2021` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | abundance_uncertainty | float | Uncertainty of relative abundance | | :cite:`Kondev2021` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | atomic_number | int | Atomic number | | | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | decay_modes | obj | Decay modes with intensities | | :cite:`Kondev2021` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | discovery_year | int | Year the isotope was discovered | | :cite:`Kondev2021` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | g_factor | float | Nuclear g-factor | | :cite:`Stone2014` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | g_factor_uncertainty | float | Uncertainty of the nuclear g-factor | | :cite:`Stone2014` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | half_life | float | Half life of the isotope | | :cite:`Kondev2021` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | half_life_uncertainty | float | Uncertainty of the half life | | :cite:`Kondev2021` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | half_life_unit | str | Unit in which the half life is given | | :cite:`Kondev2021` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | is_radioactive | bool | Is the isotope radioactive | | :cite:`iupac-masses` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | mass | float | Atomic mass | Da | :cite:`iupac-masses` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | mass_number | int | Mass number of the isotope | | :cite:`iupac-masses` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | mass_uncertainty | float | Uncertainty of the atomic mass | Da | :cite:`iupac-masses` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | parity | str | Parity, if present, it can be either `+` or `-` | | :cite:`Kondev2021` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | quadrupole_moment | float | Nuclear electric quadrupole moment | b [100 fm\ :sup:`2`] | :cite:`Stone2013` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | quadrupole_moment_uncertainty | float | Nuclear electric quadrupole moment | b [100 fm\ :sup:`2`] | :cite:`Stone2013` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ | spin | str | Nuclear spin quantum number | | :cite:`Kondev2021` | +-------------------------------+-------+------------------------------------------------------+----------------------+-------------------------+ Isotope Decay Modes =================== +-------------------------------+-------+---------------------------------------------------------------------------------+----------------------+-------------------------+ | Name | Type | Comment | Unit | Data Source | +===============================+=======+=================================================================================+======================+=========================+ | isotope_id | int | ID of the isotope | | | +-------------------------------+-------+---------------------------------------------------------------------------------+----------------------+-------------------------+ | mode | str | ASCII symbol of the decay mode | | :cite:`Kondev2021` | +-------------------------------+-------+---------------------------------------------------------------------------------+----------------------+-------------------------+ | relation | str | Uncertainty of relative abundance | | :cite:`Kondev2021` | +-------------------------------+-------+---------------------------------------------------------------------------------+----------------------+-------------------------+ | intensity | float | Intensity of the decay mode | % | :cite:`Kondev2021` | +-------------------------------+-------+---------------------------------------------------------------------------------+----------------------+-------------------------+ | is_allowed_not_observed | bool | If `True` decay mode is energetically allowed, but not experimentally observed | | :cite:`Kondev2021` | +-------------------------------+-------+---------------------------------------------------------------------------------+----------------------+-------------------------+ | is_observed_intensity_unknown | bool | If `True` decay mode is observed, but its intensity is not experimentally known | | :cite:`Kondev2021` | +-------------------------------+-------+---------------------------------------------------------------------------------+----------------------+-------------------------+ The different modes in the table are stores as ASCII representations for compatibility. The table below provides explanations of the symbols. +---------+----------------------------+------------------------------------------------------------+ | ASCII | Unicode | Description | +=========+============================+============================================================+ | A | :math:`\alpha` | :math:`\alpha` emission | +---------+----------------------------+------------------------------------------------------------+ | p | p | proton emission | +---------+----------------------------+------------------------------------------------------------+ | 2p | 2p | 2-proton emission | +---------+----------------------------+------------------------------------------------------------+ | n | n | neutron emission | +---------+----------------------------+------------------------------------------------------------+ | 2n | 2n | 2-neutron emission | +---------+----------------------------+------------------------------------------------------------+ | EC | :math:`\epsilon` | electron capture | +---------+----------------------------+------------------------------------------------------------+ | e+ | :math:`e^{+}` | positron emission | +---------+----------------------------+------------------------------------------------------------+ | B+ | :math:`\beta^{+}` | :math:`\beta^{+}` decay (:math:`\beta^{+}=\epsilon+e^{+}`) | +---------+----------------------------+------------------------------------------------------------+ | B- | :math:`\beta^{-}` | :math:`\beta^{-}` decay | +---------+----------------------------+------------------------------------------------------------+ | 2B- | 2\ :math:`\beta^{-}` | double :math:`\beta^{-}` decay | +---------+----------------------------+------------------------------------------------------------+ | 2B+ | 2\ :math:`\beta^{+}` | double :math:`\beta^{+}` decay | +---------+----------------------------+------------------------------------------------------------+ | B-n | :math:`\beta^{-}` n | :math:`\beta^{-}`-delayed neutron emission | +---------+----------------------------+------------------------------------------------------------+ | B-2n | :math:`\beta^{-}` 2n | :math:`\beta^{-}`-delayed 2-neutron emission | +---------+----------------------------+------------------------------------------------------------+ | B-3n | :math:`\beta^{-}` 3n | :math:`\beta^{-}`-delayed 3-neutron emission | +---------+----------------------------+------------------------------------------------------------+ | B+p | :math:`\beta^{+}` p | :math:`\beta^{+}`-delayed proton emission | +---------+----------------------------+------------------------------------------------------------+ | B+2p | :math:`\beta^{+}` 2p | :math:`\beta^{+}`-delayed 2-proton emission | +---------+----------------------------+------------------------------------------------------------+ | B+3p | :math:`\beta^{+}` 3p | :math:`\beta^{+}`-delayed 3-proton emission | +---------+----------------------------+------------------------------------------------------------+ | B-A | :math:`\beta^{-}\alpha` | :math:`\beta^{-}`-delayed :math:`\alpha` emission | +---------+----------------------------+------------------------------------------------------------+ | B+A | :math:`\beta^{+}\alpha` | :math:`\beta^{+}`-delayed :math:`\alpha` emission | +---------+----------------------------+------------------------------------------------------------+ | B-d | :math:`\beta^{-}` d | :math:`\beta^{-}`-delayed deuteron emission | +---------+----------------------------+------------------------------------------------------------+ | B-t | :math:`\beta^{-}` t | :math:`\beta^{-}`-delayed triton emission | +---------+----------------------------+------------------------------------------------------------+ | IT | IT | internal transition | +---------+----------------------------+------------------------------------------------------------+ | SF | SF | spontaneous fission | +---------+----------------------------+------------------------------------------------------------+ | B+SF | :math:`\beta^{+}` SF | :math:`\beta^{+}`-delayed fission | +---------+----------------------------+------------------------------------------------------------+ | B-SF | :math:`\beta^{-}` SF | :math:`\beta^{-}`-delayed fission | +---------+----------------------------+------------------------------------------------------------+ | 24Ne | 24Ne | heavy cluster emission | +---------+----------------------------+------------------------------------------------------------+ .. rubric:: Data Footnotes .. [#f1] **Atomic Weights** Atomic weights and their uncertainties were retrieved mainly from ref. :cite:`iupac-weights`. For elements whose values were given as ranges the *conventional atomic weights* from Table 3 in ref. :cite:`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 `_. .. [#f2] **Covalent Radius by Cordero et al.** In order to have a more homogeneous data for covalent radii taken from ref. :cite:`Cordero2008` the values for 3 different valences for C, also the low and high spin values for Mn, Fe Co, were respectively averaged. .. [#f3] **Electron affinity** Electron affinities were taken from :cite:`haynes2014crc` for the elements for which the data was available. For He, Be, N, Ar and Xe affinities were taken from :cite:`Andersen2004` where they were specified for metastable ions and therefore the values are negative. Updates - Electron affinity of niobium was taken from :cite:`Luo2016`. - Electron affinity of cobalt was taken from :cite:`Chen2016a`. - Electron affinity of lead was taken from :cite:`Chen2016`. .. [#f4] **Allen's configuration energies** The values of configurational energies from refs. :cite:`Mann2000a` and :cite:`Mann2000` were taken as reported in eV without converting to Pauling units. .. [#f5] **Mendeleev numbers** Mendeleev numbers were mostly taken from :cite:`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. .. [#f6] **Nuclear charge screening constants** The screening constants were calculated according to the following formula .. math:: \sigma_{n,l,m} = Z - n\cdot\zeta_{n,l,m} where :math:`n` is the principal quantum number, :math:`Z` is the atomic number, :math:`\sigma_{n,l,m}` is the screening constant, :math:`\zeta_{n,l,m}` is the optimized exponent from :cite:`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 :cite:`Clementi1967`). For elements La, Pr, Nd and Pm two exponent were reported for 4f shell denoted 4f and 4f' in :cite:`Clementi1967`. The value corresponding to 4f were used since according to the authors these are the dominant ones. .. [#f7] **van der Waals radii according to Alvarez** The bulk of the radii data was taken from Ref. :cite:`Alvarez2013`, but the radii for noble gasses were update according to the values in Ref. :cite:`Vogt2014`. .. [#f9] **Ionic radii for Actinoid (III) ions** Ionic radii values for 3\ :sup:`+` Actinoids were with coordination number 9 were taken from :cite:`Lundberg2016`. In addition ``crystal_radius`` values were computed by adding 14 pm to the ``ionic_radius`` values according to :cite:`Shannon1976`. .. [#f10] **Densities** Density values for solids and liquids are always in units of grams per cubic centimeter and can be assumed to refer to temperatures near room temperature unless otherwise stated. Values for gases are the calculated ideal gas densities at 25°C and 101.325 kPa. Original values for gasses are converted from g/L to g/cm\ :sup:`3`. For elements where several allotropes exist, the density corresponding to the most abundand are reported (for full list refer to :cite:`haynes2014crc`), namely: - Antimony (gray) - Berkelium (α form) - Carbon (graphite) - Phosphorus (white) - Selenium (gray) - Sulfur (rhombic) - Tin (white) For elements where experimental data is not available, theoretical estimates taken from :cite:`enwiki:1039678864` are used, namely for: - Astatine - Francium - Einsteinium - Fermium - Mendelevium - Nobelium - Lawrencium - Rutherfordium - Dubnium - Seaborgium - Bohrium - Hassium - Meitnerium - Darmstadtium - Roentgenium - Copernicium - Nihonium - Flerovium - Moscovium - Livermorium - Tennessine - Oganesson