FW: [Histonet] NTMT woes

[Johnson, Teri]

With permission from the email author - for your consideration.

Thanks Kemlo!

(makes sense of his email correction to the list of "hydroxide, not carbonate")


-----Original Message-----
From: Kemlo Rogerson [mailto:Kemlo.Rogerson <@t> waht.swest.nhs.uk]
Sent: Thu 9/20/2007 9:50 AM
To: Johnson, Teri
Subject: RE: [Histonet] NTMT woes
 
Magnesium chloride is the name for the chemical compounds with the
formulas MgCl2 and its various hydrates MgCl2(H2O)x. These salts are
typical ionic halides, being highly soluble in water. The hydrated
magnesium chloride can be extracted from brine or sea water. Anhydrous
magnesium chloride is the principal precursor to magnesium metal, which
is produced on a large scale.

The most common magnesium carbonate forms are the anhydrous salt called
magnesite (MgCO3) and the di, tri, and pentahydrates known as
barringtonite (MgCO3*2H2O), nesquehonite (MgCO3*3H2O), and lansfordite
(MgCO3*5H2O), respectively. Some basic forms such as artinite
(MgCO3*Mg(OH)2*3H2O), hydromagnestite (4MgCO3*Mg(OH)2*4H2O), and
dypingite (4MgCO3* Mg(OH)2*5H2O) also occur as minerals. Magnesite
consists of white trigonal crystals. The anhydrous salt is practically
insoluble in water, acetone, and ammonia. All forms of magnesium
carbonate dissolve in acids. Magnesium carbonate crystallizes in the
calcite structure wherein Mg2+ is surrounded by six oxygen atoms. The
dihydrate has a triclinic structure, while the trihydrate has a
monoclinic structure. 

Could it be there's a chemical reaction from chloride to carbonate with
the subsequent falling out of solution? Isn't it called a double
decomposition of a salt?

Kemlo Rogerson
Pathology Manager
DD   01934 647057 or extension 3311
Mob 07749 754194; Pager 07659 597107;


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