5% Aqueous HAuCl4
In aqueous gold chloride reagent, residue (5 μg) of 2-EMC dissolved in either water, 10% hydrochloric acid or 10% acetic acid characteristic large clear crystals. The crystals grow as large, thick tablets that are stacked. The crystals are very bright under crossed polars.
The crystals are very well-suited for single crystal infrared spectroscopy.
5% HAuCl4 in 1:2 concentrated H2SO4: H20
2-EMC forms colorless prisms that form as twins. The drop initially oils very heavily and crystals form slowly (15-20 min) while clearing the oil. The crystals are not very bright under crossed polars and the edges of the crystals appear white against the dark background while the body of the crystals appear dark.
Gold Bromide (HAuBr4)
2-EMC with gold bromide grows characteristic red twig like growths. This shape is a composite of individual flat hexagonal plates that grow strung together in different orientations. The individual plates appear bright in some orientations under crossed polars.
Platinic Chloride (H2PtCl6)
Under acidic conditions of 10% hydrochloric acid, 2-EMC with aqueous platinic chloride forms thick, long, colorless prisms that grow end to end as straight or branched chains. The crystals display bright interference colors in crossed polars with different parts of the composite growing dark at different angles.
The crystals maybe very thick for good transmission infrared spectra but sufficient peak information can be obtained.
Platinic Bromide (H2PtBr6)
2-EMC forms crystals in two concentration dependent forms with platinic bromide reagent. The more common form of these crystals are the long blades with one angled edge. The crystal appears bright under crossed polars and goes extinct in some angles. The second form of crystals observed are sheaves of short red rods that are very bright under crossed polars.