Date: Tue, 16 Aug 2011 09:46:29 -0400
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: ACTSNYC**At_Symbol_Here**CS.COM
Subject: CAS #s for allotropes of phosphorus

Is anyone out there, or does anyone know, an expert on the allotropes of phosphorus?
I'm working on the health effects for the chemicals listed in the next edition of the Dictionary of Pyrotechnics--a freebie for a pal I work with on NFPA 1126, the standard of pyro before a proximate audience.

My old Hawleys gives on CAS # 7723-14-0 to all forms and says elemental phosphorus can have allotropes that are "white (or yellow), red, and black."  Other references list a brown allotrope as well. 

Here's the deal. ACGIH has two entries in their big exposure guide booklet:

* White phosphorus CAS# 7723-14-0 which has no TLV, but a DFG MAK 0.05 mg/m3.

* Yellow phosphorus CAS# 12185-10-3 has a TLV-TWA 0.1 mg/m3; MAK 0.05 and a NIOSH REL of 0.1 mg/m3.

And there's no entry for red phosphorus or any other color.

Pyrotechs use white and red.  And their suppliers as well as other experts list the White as CAS 7723-14-0 and Red as 12185-10-3.  And if I google various sources I can get different CAS numbers almost at will. They all contradict each other.

Does anyone know if white and yellow are really different allotropes?   Does anyone know which CAS # goes with which?    Specifically is the CAS# 12185-10-3 for yellow or for red?  It's to look like ACGIH might be wrong on this one.

Thanks for thinking on this.


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