Module elements 

Element table, Z = 1..=92.

The table is const data with no I/O, so table builders and a WASM front end can use it directly. Provenance is also recorded in docs/data-provenance.md.

Sources

• Atomic weight (atomic_weight, g/mol, i.e. relative atomic mass): the CIAAW / IUPAC standard atomic weights as tabulated at https://www.ciaaw.org/atomic-weights.htm (“Standard Atomic Weights 2024”: the 2021 report, T. Prohaska et al., “Standard atomic weights of the elements 2021”, Pure Appl. Chem. 94, 573 (2022), doi:10.1515/pac-2019-0603, plus the CIAAW 2024 revisions of Gd, Lu and Zr). For the 14 elements whose standard weight is an interval (H, Li, B, C, N, O, Mg, Si, S, Cl, Ar, Br, Tl, Pb) the single value is the abridged value of https://www.ciaaw.org/abridged-atomic-weights.htm, which the 2021 report (Table 1, column 7) says replaces, and equals, the former conventional atomic weights; for H that value is printed 1.0080, the former conventional 1.008. Elements with no standard atomic weight (Tc, Pm, Po, At, Rn, Fr, Ra, Ac) carry the mass number of their longest-lived isotope as listed by CIAAW at https://www.ciaaw.org/radioactive-elements.htm (from NUBASE2020, F. G. Kondev et al., Chin. Phys. C 45, 030001 (2021)) and have weight_is_mass_number == true; that is a convention, not a measurement of a natural mixture. For Tc that page lists 97 and 98 as equally long-lived; 98 is used. All 92 entries checked against these pages on 2026-10-06 (#15).

• Density (density_g_cm3): density of the solid, g/cm³, as printed in A. Thompson et al., X-Ray Data Booklet, LBNL/PUB-490 Rev. 3 (Lawrence Berkeley National Laboratory, October 2009), section 5.2, Table 5-2 “Properties of the elements”, pp. 5-5 to 5-8 (https://xdb.lbl.gov/xdb-new.pdf, PDF pages 153-156). Section 5.2 says the data were taken mostly from D. R. Lide (ed.), CRC Handbook of Chemistry and Physics, 80th ed. (CRC Press, 1999), and that densities are specific gravities at 20 °C unless a superscript gives another temperature (25 °C for Si, Sc, Ni, Zn, Ge, Y, La, Ce, Nd, Pm, Sm, Eu, Gd, Dy, Ho, Er, Tm, Lu; V 18.7 °C, Ga 29.6 °C, Ir 17 °C). Tc and Pa are marked “calculated” there, U “~18.95”. The table names no allotrope except graphite for C. All populated entries checked on 2026-10-07 (#15; the PDF’s SHA-256 is recorded in docs/data-provenance.md), and 37 values set to the printed ones. Four entries the booklet does not pin were checked on 2026-10-07 (#15) against other open primary compilations, all U.S. government reports:

  • Cr 7.20 (was 7.15, which lay outside the booklet’s printed range 7.18-7.20): the upper end of that range, and the density “calculated from the NBS lattice constant”, 7.200 at 25 °C, in H. E. Swanson, R. K. Fuyat and G. M. Ugrinic, Standard X-ray Diffraction Powder Patterns, NBS Circular 539, Vol. V (1955), p. 20 (https://nvlpubs.nist.gov/nistpubs/Legacy/circ/nbscircular539v5.pdf). This is an X-ray (crystal) density.
  • Au 19.30: the booklet prints “~19.3”; NBS Circular 539, Vol. I (Swanson and Tatge, 1953), p. 33, prints 19.302 at 25 °C from its lattice constant (https://nvlpubs.nist.gov/nistpubs/Legacy/circ/nbscircular539v1.pdf).
  • Ra 5.0: no density in the booklet; “a specific gravity of approximately 5.0” in H. W. Kirby and M. L. Salutsky, The Radiochemistry of Radium, NAS-NS 3057 (1964), p. 3, citing the International Critical Tables (https://www.osti.gov/servlets/purl/4560824).
  • Ac 10.07: no density in the booklet; the crystal density of fcc Ac metal (a = 5.311 Å), Table 4, p. 11, of J. D. Farr, A. L. Giorgi, M. G. Bowman and R. K. Money, “The crystal structure of actinium metal and actinium hydride”, Los Alamos report LA-1545 (1953) (https://www.osti.gov/servlets/purl/4397640), published as J. Inorg. Nucl. Chem. 18, 42 (1961).

  Still not verified to their stored digits: C 2.267 (printed as the range 1.9-2.3) and Mn 7.44 (the upper end of the printed range 7.21-7.44). For Mn, the X-ray density of alpha-Mn, “(calculated) 7.475 g/cm³” at 25 °C (a = 8.9121 Å, Z = 58), is printed in M. C. Morris et al., Standard X-ray Diffraction Powder Patterns, NBS Monograph 25, Section 17 (1980), p. 50 (https://nvlpubs.nist.gov/nistpubs/Legacy/MONO/nbsmonograph25-17.pdf, checked 2026-10-07, #15). It lies above the booklet’s range, so unlike Cr it does not pin a value inside that range; 7.44 is kept, unverified. Si keeps 2.329: the booklet prints 2.33 at 25 °C, and 2.329 is the crystal density M(Si) / V_m(Si) from the CODATA 2022 “molar volume of silicon” (1.205 883 199e-5 m³/mol, https://physics.nist.gov/cuu/Constants/Table/allascii.txt) for any weight in the standard interval [28.084, 28.086]. The specific gravities are used as g/cm³; the booklet does not state the reference water state. Later CRC editions may differ; none was seen. It is None where no solid density at ambient conditions exists (gases: H, He, N, O, F, Ne, Cl, Ar, Kr, Xe, Rn; liquids: Br, Hg; no data: At, Fr). Densities are a default for a pure element only; compounds need an explicit density override.

• Sublimation (cohesive) enthalpy (default_surface_binding_ev): where a measured value is tabulated, the cohesive energy per atom (eV) of C. Kittel, Introduction to Solid State Physics, 8th ed. (Wiley, 2005), chapter 3 (cohesive energies of the elements), which is the enthalpy of atomization at 0 K. Using it as the surface binding energy E_s is the usual binary-collision convention (Sigmund, Phys. Rev. 184, 383 (1969)), not a measured surface barrier. Elements left None must have E_s set explicitly by the user rather than have one invented. Verified on 2026-10-07 (#15) against Table 1 “Cohesive energies”, chapter 3, p. 50 of the 8th edition (Wiley, 2005, ISBN 0-471-41526-X; edition, publisher and ISBN read from the title and copyright pages of the copy used, see docs/data-provenance.md). The table prints each element in kJ/mol, eV/atom and kcal/mol (“energy required to form separated neutral atoms in their ground electronic state from the solid at 0 K at 1 atm. The data were supplied by Prof. Leo Brewer.”); the eV/atom value is used, to the digits printed. All 35 populated entries were compared: 33 equal the printed value, and Na (was 1.11) and K (was 0.93) were set to the printed 1.113 and 0.934. The table also prints values for elements left None here (among them N, O, P, S, Sc, Mn, Se, the rare gases and most lanthanides and actinides); those defaults stay unset, since #15 audits the populated entries only. Earlier cross-check, kept as a test: L. Brewer, “The cohesive energies of the elements”, report LBL-3720 (1975), Table I, kcal/gram-atom (https://www.osti.gov/servlets/purl/7187973).

• Displacement energy (default_displacement_ev): threshold displacement energies as recommended in ASTM E521 (“Standard Practice for Investigating the Effects of Neutron Radiation Damage Using Charged-Particle Irradiation”), the convention underlying the NRT damage model (Norgett, Robinson, Torrens, Nucl. Eng. Des. 33, 50 (1975)). These are conventions for damage accounting, not measured properties of a specific crystal direction. None where no convention value is recorded. Not verified: the standard could not be reached (see docs/data-provenance.md). The values are also not those of the Greenwood-Smither compilation used by SPECTER and NJOY (they differ for Al, Ti, Cu, Nb and Ag), which is not E521 either.

Structs

Element

One element of the periodic table with its default data.

Constants

NUM_ELEMENTS

Number of elements in the table.

Statics

ELEMENTS

The table, indexed by Z - 1.

Functions

element

Look an element up by atomic number (1..=92).

element_by_symbol

Look an element up by case-sensitive symbol ("Si", not "si").