Chemistry and crystals

Our logo summarizes our two passions: Microscopy and Chemistry. It represent the crystals of lead iodide (PbI2), observed under the microscope (100x):

plomo mimetita prueba yoduro web

These crystals were observed in the chemical microscopy test for lead, using potassium iodide. Is a rapid and reliable qualitative test for lead in minerals and metals. The classic chemical microscopy, developed in the XIX and first half of XX centuries, included hundreds of microchemical tests. It was a routine technique in mineralogy. The development and generalization of spectroscopic techniques, more sensitive, simple and precise, move the classic chemical microscopy to the History of Science. Anyway, the chemical microscopy techniques will be useful for ever: does not depend on technology, only in the chemical properties of substances, are beautiful determinations and its didactic potential is remarkable.

If you have a conventional optical microscope, you can see this crystals for yourself:

  • Take a minute quantity of mineral powder or a fragment less than 1 mm in the end microscope slide. Add a small drop (about 10 microliters)  of nitric acid 1:1 and gently heat by the flame of an alcohol burner. Avoid the drop boils up.
  • Once evaporated all acid, redissolve the dry residue in a drop of distilled water and transfer the liquid to the center of the slide. Using a toothpick, add a particle of solid potassium iodide. If are lead present, a yellow precipitate will form.
  • Cover with a coverslip and observe under microscope. The hexagonal crystals of lead iodide are distinct and confirms the presence of lead in sample.

With our logo, we tried to pay tribute to the history of the microscopic techniques, which decisively contributes to the development of modern Science.

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