Date: Tue, 16 Aug 2011 13:44:33 -0600
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From: Alan Hall <ahalltoxic**At_Symbol_Here**MSN.COM>
Subject: Re: CAS #s for allotropes of phosphorus
In-Reply-To: <1313519573.46438.YahooMailClassic**At_Symbol_Here**>

Perhaps the "right" answer is to go to the CAS STN database and see what they have on it?

Date: Tue, 16 Aug 2011 11:32:53 -0700
From: dura_chemiker**At_Symbol_Here**YAHOO.COM
Subject: Re: [DCHAS-L] CAS #s for allotropes of phosphorus
To: DCHAS-L**At_Symbol_Here** LIST.UVM.EDU

I read your E-mail inquiry regarding various allotropes of phosphorous and immediately opened my Merck Index.  According to the Merck, t here is only one CAS number for phosphorous [7723-14-0].  They do no t provide individual CAS numbers for the different allotropes.  It a lso states that there are three main allotropic forms: white, black and r ed.  White is sometimes refered to as yellow as a result of impuriti es, while red is sometimes refered to as violet.  I also checked t he CRC Handbook of Chemistry and Physics just for confirmation.  ; The Merck Index provides some health and safety information.
John D. Turner

--- On Tue, 8/16/11, ACTSNYC**At_Symbol_Here**CS.COM <ACTSNYC**At_Symbol_Here**CS.COM > wrote:

From: ACTSNYC**At_Symbol_Here**CS.COM <ACTSNYC**At_Symbol_Here**CS.COM >
Subject: [DCHAS-L] CAS #s for allotropes of phosphorus
To: DCH AS-L**At_Symbol_Here**LIST.UVM.EDU
Date: Tuesday, August 16, 2011, 6:46 AM

Is anyone out there, or does anyone know, an expert on th e allotropes of phosphorus?
I'm working on the health effec ts for the chemicals listed in the next edition of the Dictionary of Pyrote chnics--a freebie for a pal I work with on NFPA 1126, the standard of pyr o 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 br own allotrope as well. 

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

* White phosphorus CAS# 772 3-14-0 which has no TLV, but a DFG MAK 0.05 mg/m3.

* Yellow phosph orus 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 col or.

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.&nb sp; And if I google various sources I can get different CAS numbers almos t at will. They all contradict each other.

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

Thanks for thinking on this.

Monona< BR>

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