Molar Gas Constant

The ideal gas law's constant R, the exact product of the Avogadro and Boltzmann constants.

Specifications & Metrics

symbol

R

status

Exact — derived from defining constants

value

8.314462618 J·mol⁻¹·K⁻¹

Relative Scale in Constants

Core Principles & Analysis

• Appears in the ideal gas law PV = nRT.
• Exactly N_A times k_B: the per-mole face of the per-molecule Boltzmann constant.
• Set exactly by the 2019 redefinition, ending its era as a measured quantity.

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