Fix unit for `Element` properties: `density_of_solid` and `Molar volume` by DanielYang59 · Pull Request #4454 · materialsproject/pymatgen

DanielYang59 · 2025-07-11T07:49:51Z

Summary

Remove unit in docstring for Element properties, to close Units in docstring appear to be wrong for density_in_solid #4453
Check other units in docstring

DanielYang59 · 2025-07-11T13:46:15Z

dev_scripts/periodic_table_resources/_periodic_table.yaml

    Np: 4273, Pu: 3503, Am: 2880, Cm: 3383}
 Brinell hardness:
-  unit: MN m^-2
+  unit: MPa


This could be breaking.

These two units are exactly the same but feels like MPa might be more common than MN m^-2 (also more consistent with docstring and other hardness)?

pymatgen/src/pymatgen/core/periodic_table.py

Lines 107 to 112 in f9d9fe8

bulk_modulus (float, optional): Bulk modulus (GPa).

youngs_modulus (float, optional): Young's modulus (GPa).

brinell_hardness (float, optional): Brinell hardness (MPa).

rigidity_modulus (float, optional): Rigidity modulus (GPa).

mineral_hardness (float, optional): Mohs hardness.

vickers_hardness (float, optional): Vickers hardness (MPa).

DanielYang59 · 2025-07-11T13:51:28Z

src/pymatgen/core/periodic_table.py

            mineral_hardness (float, optional): Mohs hardness.
            vickers_hardness (float, optional): Vickers hardness (MPa).
-            density_of_solid (float, optional): Density in solid phase (g/cm³).
+            density_of_solid (float, optional): Density in solid phase (kg/m³).


I have no strong opinion on this, I originally thought we just remove all units from the docstring if it's a scalar and redirect people to get the unit from FloatWithUnit, but feels like it's not good for docstring clarity as most data for ptable wouldn't be updated very often, also many units are pretty much "singleton" (e.g. K for temperature, angstrom for radii,...):

pymatgen/src/pymatgen/core/periodic_table.py

Lines 84 to 116 in f9d9fe8

Attributes:

Z (int): Atomic number of the element.

symbol (str): Element symbol (e.g., "H", "Fe").

long_name (str): Full name of the element (e.g., "Hydrogen").

A (int, optional): Atomic mass number (sum of protons and neutrons).

atomic_radius_calculated (float, optional): Calculated atomic radius (Å).

van_der_waals_radius (float, optional): Van der Waals radius (Å).

mendeleev_no (int, optional): Mendeleev number based on crystal-structure maps.

electrical_resistivity (float, optional): Electrical resistivity (Ω·m).

velocity_of_sound (float, optional): Velocity of sound (m/s).

reflectivity (float, optional): Reflectivity (%).

refractive_index (float, optional): Refractive index.

poissons_ratio (float, optional): Poisson's ratio.

molar_volume (float, optional): Molar volume (cm³/mol).

electronic_structure (str): Electronic structure (e.g., "[Ar].3d6.4s2").

atomic_orbitals (dict): Orbital energies (Hartree units).

atomic_orbitals_eV (dict): Orbital energies in electron volts (eV).

thermal_conductivity (float, optional): Thermal conductivity (W/m·K).

boiling_point (float, optional): Boiling point (K).

melting_point (float, optional): Melting point (K).

critical_temperature (float, optional): Critical temperature (K).

superconduction_temperature (float, optional): Superconducting transition temperature (K).

liquid_range (float, optional): Temperature range for liquid phase (K).

bulk_modulus (float, optional): Bulk modulus (GPa).

youngs_modulus (float, optional): Young's modulus (GPa).

brinell_hardness (float, optional): Brinell hardness (MPa).

rigidity_modulus (float, optional): Rigidity modulus (GPa).

mineral_hardness (float, optional): Mohs hardness.

vickers_hardness (float, optional): Vickers hardness (MPa).

density_of_solid (float, optional): Density in solid phase (g/cm³).

coefficient_of_linear_thermal_expansion (float, optional): Thermal expansion coefficient (K⁻¹).

ground_level (float, optional): Ground energy level of the element.

ionization_energies (list[Optional[float]]): Ionization energies (kJ/mol), indexed from 0.

DanielYang59 added 2 commits July 11, 2025 10:09

remove unit in docstring for density of solid

080d31d

add unit hatree to "Atomic orbitals"

97bd8b2

DanielYang59 force-pushed the element-property-unit branch from 1190a26 to 97bd8b2 Compare July 11, 2025 08:10

DanielYang59 added 2 commits July 11, 2025 10:17

fix unit for molar volume

f878e6c

maybe recover unit in docstring, need discussion

6a4159b

DanielYang59 changed the title ~~Remove unit in docstring for Element properties~~ Fix unit for Element properties: density_of_solid and Molar volume Jul 11, 2025

MN m^-2 -> MPa for Brinell and Vickers hardness

a60881f

DanielYang59 commented Jul 11, 2025

View reviewed changes

DanielYang59 marked this pull request as ready for review July 11, 2025 13:52

DanielYang59 requested review from mkhorton and shyuep as code owners July 11, 2025 13:52

shyuep merged commit 2f2c8d7 into materialsproject:master Jul 29, 2025
44 checks passed

DanielYang59 deleted the element-property-unit branch July 29, 2025 16:22

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Fix unit for `Element` properties: `density_of_solid` and `Molar volume`#4454

Fix unit for `Element` properties: `density_of_solid` and `Molar volume`#4454
shyuep merged 5 commits intomaterialsproject:masterfrom
DanielYang59:element-property-unit

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	bulk_modulus (float, optional): Bulk modulus (GPa).
	youngs_modulus (float, optional): Young's modulus (GPa).
	brinell_hardness (float, optional): Brinell hardness (MPa).
	rigidity_modulus (float, optional): Rigidity modulus (GPa).
	mineral_hardness (float, optional): Mohs hardness.
	vickers_hardness (float, optional): Vickers hardness (MPa).

	Attributes:
	Z (int): Atomic number of the element.
	symbol (str): Element symbol (e.g., "H", "Fe").
	long_name (str): Full name of the element (e.g., "Hydrogen").
	A (int, optional): Atomic mass number (sum of protons and neutrons).
	atomic_radius_calculated (float, optional): Calculated atomic radius (Å).
	van_der_waals_radius (float, optional): Van der Waals radius (Å).
	mendeleev_no (int, optional): Mendeleev number based on crystal-structure maps.
	electrical_resistivity (float, optional): Electrical resistivity (Ω·m).
	velocity_of_sound (float, optional): Velocity of sound (m/s).
	reflectivity (float, optional): Reflectivity (%).
	refractive_index (float, optional): Refractive index.
	poissons_ratio (float, optional): Poisson's ratio.
	molar_volume (float, optional): Molar volume (cm³/mol).
	electronic_structure (str): Electronic structure (e.g., "[Ar].3d6.4s2").
	atomic_orbitals (dict): Orbital energies (Hartree units).
	atomic_orbitals_eV (dict): Orbital energies in electron volts (eV).
	thermal_conductivity (float, optional): Thermal conductivity (W/m·K).
	boiling_point (float, optional): Boiling point (K).
	melting_point (float, optional): Melting point (K).
	critical_temperature (float, optional): Critical temperature (K).
	superconduction_temperature (float, optional): Superconducting transition temperature (K).
	liquid_range (float, optional): Temperature range for liquid phase (K).
	bulk_modulus (float, optional): Bulk modulus (GPa).
	youngs_modulus (float, optional): Young's modulus (GPa).
	brinell_hardness (float, optional): Brinell hardness (MPa).
	rigidity_modulus (float, optional): Rigidity modulus (GPa).
	mineral_hardness (float, optional): Mohs hardness.
	vickers_hardness (float, optional): Vickers hardness (MPa).
	density_of_solid (float, optional): Density in solid phase (g/cm³).
	coefficient_of_linear_thermal_expansion (float, optional): Thermal expansion coefficient (K⁻¹).
	ground_level (float, optional): Ground energy level of the element.
	ionization_energies (list[Optional[float]]): Ionization energies (kJ/mol), indexed from 0.

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DanielYang59 commented Jul 11, 2025 •

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