PN also called Sodium formaldehyde bisulfite,the Cas No.is 870-72-4.And the molecular formular is CH₅NaO₄S. It is yellowish translucent liquid and used as brightener for Nickel Plating. 
Uses:
1.Used as heavy metal complexing agent for nickel plating. 
2.It can be used in the range of 15℃～45℃. PN is not only suitable for acid copper, but also can be used as brightener for cyanide-free zinc plating.. 
3.PN is the best high-temperature carrier in acid copper brightener, suitable for complex workpiece electroplating.
4.It has a very strong cathodic polarization effect, which can significantly enhance the brightness of the low area. When using PN, it is found that the brightness is insufficient, and the amount of high-level agent (polydisulfide) can be appropriately increased.
5.Used as brightener for nickel plating, can improve the brightness and leveling effect.

Chemical name:PN
Other name:Sodium formaldehyde bisulfite
Molecular formula:CH₅NaO₄S
Molecular weight:136.1
CAS NO.:870-72-4
Appearance:  yellowish translucent liquid
Assay:28%
Package:25kg/drum