[AMRadio] Re: Rochelle salts

Jim Candela jcandela at prodigy.net
Mon Nov 20 09:08:38 EST 2006


   It looks like the stuff can be used as a laxative (purgative).


Potassium sodium tartrate
From Wikipedia, the free encyclopedia
(Redirected from Rochelle salt)

Systematic name     Potassium sodium tartrate
Chemical formula     KNaC4H4O6·4H2O.
Molecular mass     282.1 g/mol
Relative density     1.79
Melting point     75 °C
Boiling point     220 °C
CAS number     [304-59-6 (Anhydrous); 6381-59-5 (Tetrahydrate)]
SMILES     KNaC4H4O6 . 4H2O

Potassium sodium tartrate is a double salt first prepared (in about 1675) by an apothecary, Pierre Seignette, of La Rochelle, France. As a result the salt was known as Seignette's salt or Rochelle salt.

It is a colorless to blue-white salt crystallizing in the orthorhombic system. Its molecular formula is KNaC4H4O6·4H2O. It is slightly soluble in alcohol but more completely soluble in water. It has a specific gravity of about 1.79, a melting point of approximately 75 °C, and has a saline, cooling taste.

It has been used medicinally as a purgative but in more recent years its piezoelectric properties have been more important and it has found usage in phonograph pickups and other sensing devices. It has also been used in the process of silvering mirrors. It is an ingredient of Fehling's solution, formerly used in the determination of reducing sugars in solutions.

In organic synthesis, it is used in aqueous workups to break up emulsions, particularly for reactions in which an aluminum-based hydride reagent was used.

Rochelle salt can be made from common household goods: cream of tartar and washing soda. In part because of the steep temperature dependence on solubility, large crystals of Rochelle salt are easy to grow.

----- Original Message ----
From: "DOXEMF at aol.com" <DOXEMF at aol.com>
To: Discussion of AM Radio in the Amateur Service <amradio at mailman.qth.net>
Sent: Monday, November 20, 2006 12:17:16 AM
Subject: [AMRadio] Re: Rochelle salts

I found a couple tubes of mushroomed Rochelle salts in with some old tube gear. They are/were originally about 2X3 inches
in a cardboard tube with cardboard end caps.
  Is there any use for this stuff or health concerns?

Bill KB3DKS/1
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