Sciencemadness Discussion Board

NaNO3 (NO2)

YT2095 - 11-9-2006 at 09:16

I`ve looked up NaNO3 in my book and the decop temp is marked as 653k

now IIRC it`s supposed to decomp to NaNO2, but THAT decop temp is marked as 593k !?

is my book in error again (there`s been 4 so I`ve had to correct).

hodges - 13-9-2006 at 17:38

I see 320C for NaNO2 and 380C for NaNO3 in my CRC handbook. Those are the same numbers, but they still could both be in error I guess if two books got them from the same place.

Hodges

bereal511 - 13-9-2006 at 19:57

That would be an impressive error, because I get the same numbers for their corresponding decomposition points across the internet. Seems a bit strange.

Rosco Bodine - 13-9-2006 at 23:55

http://www.ussaltllc.com/sntechbulletin.htm

Thermal decomposition of pure sodium nitrite does not occur at an appreciable rate below 600C (1112F). In air, a barely detectable exotherm is observed in the range of 370-440C (698-824F) when heated very, very slowly. This probably indicates oxidation to the nitrate.

In a nitrogen atmosphere, decomposition becomes detectable at 490-500C (914-932F). The rate of decomposition increases with temperature and is complete at 920C (1688F). Sodium oxide remains after the decomposition.*

*E.S. Freeman, J. Phys. Chem., 60, 1487 (1956).