Muon molar mass

$M(μ)$ = 1.134 289 258(25) × 10⁻⁴ kg mol⁻¹

Value: 1.134 289 258 × 10⁻⁴ kg mol⁻¹
Standard uncertainty: 2.5 × 10⁻¹² kg mol⁻¹
Relative uncertainty: 2.2 × 10⁻⁸ (22 parts per billion)
Status: Measured
Symbol: $M(μ)$
Source: CODATA 2022 via NIST · NIST entry

Use in a calculation

# muon molar mass, CODATA 2022 (NIST)
muon_molar_mass = 1.134289258e-4  # kg mol^-1, standard uncertainty 2.5e-12

# SciPy: scipy.constants.physical_constants['muon molar mass']

What it is

The mass of one mole of muons (muon), in kilograms per mole.

How the value changed, 1998–2022

Each point is one CODATA adjustment, plotted as its difference from the 2022 value; the bars show one standard uncertainty (an arrowhead means the bar runs off the chart).

Relative uncertainty

CODATA	Value (uncertainty)	Relative uncertainty	Change from previous
2022	1.134 289 258(25) × 10⁻⁴	2.2 × 10⁻⁸	−0.0 σ of 2018
2018	1.134 289 259(25) × 10⁻⁴	2.2 × 10⁻⁸	+0.1 σ of 2014
2014	0.113 428 9257(25) × 10⁻³	2.2 × 10⁻⁸	−0.3 σ of 2010
2010	0.113 428 9267(29) × 10⁻³	2.6 × 10⁻⁸	+0.4 σ of 2006
2006	0.113 428 9256(29) × 10⁻³	2.6 × 10⁻⁸	−0.3 σ of 2002
2002	0.113 428 9264(30) × 10⁻³	2.6 × 10⁻⁸	+2.8 σ of 1998
1998	0.113 428 9168(34) × 10⁻³	3.0 × 10⁻⁸

“Change from previous” is the shift in the value divided by the standard uncertainty of the previous adjustment. Earlier values are converted into the current unit where NIST changed it (for example J s to J Hz⁻¹).