Clarification Regarding the conditions for STP

[Conservation]

Hello all,

I am currently in possession of two chemistry textbooks, Changs and Atkins, which I believe are both fairly new versions. Changs defines STP at 25 degrees Celsius and 1 atm, and Atkins defines STP at 25 degrees Celsius and 1 bar; I understand that numerically it would not make a huge difference (1 atm=101.3 kpa=almost 100 kpa), but which is technically correct?

Thanks.

 

[Borek]

There is no one, universally accepted definition of STP. Bar is a recommended pressure for a standard state.

 

[Yanick]

Atmospheres were used for something like 100 years until "they" decided to switch standard pressure to 1 bar. Numerically they are nearly identical, obviously.

Ref: http://goldbook.iupac.org/S05921.html
(Getting a lot of mileage out of IUPAC today )