Hello, I am trying to find out about the bulk properties of commercial Phosphorus Pentanitride, P3N5. It is used as a gettering material for incandescent lamps, the filament assemblies being dipped into a suspension of it in amyl acetate or chloroform. I know that the high purity substance is white crystals, but the commercial grade product has a buff to pale pink colouration. Looking around on the internet one can find a description of its colour, stated as being "white to red", the same description being repeated on many sites. It looks as if someone has looked into a recent edition of "CRC" or the "Merck Index", (My editions of these two references are 20 years old, and contain no reference to this binary compound, hence this post!) and posted what they read on their site, all the others simply copying like ducklings following the mother duck, none ever having actually seen any actual P3N5, let alone experimented upon any! I have also found out that there are at least two different crystalline modifications, an Alpha and Beta form with a transition temperature up in the 600*C region.I am basically after the basic things, crystalline form and colour, melting, boiling, sublimation/decomposition temperatures, solvent solubilities etc.
For similar reasons I am also looking for similar data on Halophosphonitriles, (PNX2)n, where X=Br in my case and n=3 or 4.
I have found some good descriptions for compounds where X=Cl, and n=3-7, in terms of solvent solubilities, (basically benzene for lower values of n), and melting/boiling points at different pressures, but nothing for the X=Br analogs. These are used to getter Some types of Tungsten Halogen Lamps and dose them with bromine in the same operation.
If anyone is working on Group-V elements in their lab or in a lamp works, or simply has access to more recent copies of references like "CRC" or "Merck" with some data for these compounds, I would be very appreciative!
Thanks, Andrew