Tartrate Crystals Grown by the Standard Technique

CALCIUM TARTRATE CRYSTALS GROWN BY THE STANDARD TECHNIQUE 

Calcium tartrate is the easiest of all gel-growth experiments and yields the best results of all materials.1 2 Thus it has been the most used system for gel-growth studies, including nucleation, aging, and pH studies. 

The gel in this case is formed containing sodium tartrate and sodium hydrogen tartrate. About SO mL of 0.5 M tartaric acid is titrated with 0.S M sodium metasilicate to a pH of 4. After titration the solution is placed into 50-mL test tubes and allowed to set. About 30 mL of solution is added to each tube. The tubes should set for 1 or 2 days. Fifteen milliliters of a 0.S M CaCl2 solution is then added above the gel in each tube and the tubes are lightly stoppered. They are then placed in a controlled-temperature bath at 40°C in the dark. Close temperature control is not needed. The reaction time is about 2 weeks. 

Clear crystals up to 1 cm in length have been produced in test tubes, but 5-mm crystals are more common. Crystals twice this size can be produced using 500-mL graduates in place of small test tubes. In this case 2 to 3 months of reaction time is required. 

COPPER (I) CHLORIDE CRYSTALS GROWN BY THE COMPLEX DILUTION METHOD 

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A. CALCIUM TARTRATE CRYSTALS GROWN BY THE STANDARD TECHNIQUE... 

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