Chemis-Tree Traditions

It was a great delight to read the Newscripts column and find out that ours was not the only lab to "repurpose" our equipment during the holiday season (C&EN, Dec. 21, 2009, page 56). Our "Chemis-Tree" tradition began in 1986 and continues to this day. Every year, a new version is constructed. No two trees are ever alike.

All of the colors associated with them are produced by chemical reactions and standard indicator solutions. A brilliant red is achieved in the presence of calcium and magnesium ions using an indicator containing calmagite. The same indicator yields a very nice blue in the absence of the aforementioned ions. Different shades of yellow can be made employing a vanadate-molybdate reagent and various concentrations of phosphate. Bromcresol green in deionized water produces an acceptable green. Altering the pH to the acid or alkaline side gives gold and blue, respectively. Most of these colorimetric chemistries can be found in "Standard Methods."

Perhaps the most challenging and somewhat difficult part is coming up with different glassware configurations and, of course, "balancing" them. Some versions have been more than 4 feet tall. Needless to say, many current and former employees have enjoyed the display.

Edward Robakowski
Newbury, Ohio