https://doi.org/10.1351/goldbook.S05921
Chosen value of pressure denoted by \(p^{\unicode{x29B5}}\) or \(p^{\,\unicode{x26ac}}\). In 1982 IUPAC recommended the value \(10^{5}\ \text{Pa}\), but prior to 1982 the value \(101\ 325\ \text{Pa}\) (= \(1\ \text{atm}\)) was usually used.