I have a passion for microscope, and have over the years started to improve my setup to allow me to capture all manner of things. The most recent addition (June 2016) was the purchase of a polarizing retrofit kit for my Radical RXL-4T Microscope and my Nikon DSLR.
A polarizing microscope is an often undervalued tool which allows the microscopist to control which light reaches the objective based on the polarization of the light. One of the great features of Polarized Light Microscopy is the fantastic color that arises from a number of ‘optically active' samples as a result of double-refraction or Birefringence . This double-refraction occurs because materials in a molecularity ordered compound can be either Isotropic (the index of refraction is equal in all directions) or they can be anisotropy (the spatial distribution of properties is non-uniform, e.g. refraction), it is the non-uniform refraction that creates the fascinating colors.
Whilst I have some chemistry background through university, I am far more biologically inclined so this article is designed to share some of the findings I had around which organic and inorganic materials formed crystals or optically active lattices. Over time I will aim to update this article with links to individual chemicals which had an interesting crystal structure or that were optically active and write-ups on each.
It should be noted that the following experiments were conducted in a chemistry laboratory, with appropriate PPE. Because most if not all of these chemicals are considered toxic, the following should not be repeated except in a controlled and safe environment.
In most cases, I have dissolved the respective chemical in either water or a specific solvent, placed this directly on a microscope slide and through heating attempted to remove the solvent…
Chemical | Notes |
Calcium Carbonate | Did not form crystals |
Potassium Permanganate | Formed crystals |
Copper Acetate | Formed crystals |
Stannus Chloride | Formed crystals |
L-Glutamic Acid | Formed tree like crystals |
Starch | Formed bubbles |
Sulfur in Carbon Disulphide | Formed crystals |
Mannitol | Formed crystals |
Magnesium Chloride | Did not form crystals |
Potassium Carbonate | Formed small crystals |
Magnesium Sulphide | Formed crystals |
Citric Acid | Formed crystals |
Monosodium Glutamate | Did not form crystals |
D-Fructose | Did not dry under heat |
ALS Ferric | Formed crystals |
Copper Sulfide | Formed some crystals |
Fructose | Did not dry under heat |
Quinol | Formed crystals |
Vitamin B6 | Formed crystals |
Aluminium Chloride | Formed crystals |
L-Alinine | Formed crystals |
Sodium Carbonate | Formed crystals |
Boric Acid | Did not form crystals |
Sorbic Acid | Formed crystals |
Vitamin B (Palminate) | Did not form crystals |
Tin Chloride | Formed crystals |
Lithium Chloride | Did not form crystals |
Lactic Acid | Did not form crystals |
Acetamide | Did not form crystals |
Vitamin E Acetate | Did not form crystals, did not dry at temperature |
Iodine | Formed crystals |
Sodium Persulphate | Formed crystals |
Vitimin A Acetate | Did not form crystals |
Caffeine in Methanol | Formed crystals |
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