The crystal habit modification of inorganic salts with dyes. Part 1.—General considerations

Abstract

The crystal habit modifying powers of dyes depend both on their anionic and cationic polar substituent groups, and the nature of their substitution. The positions of polar substitution of the dye molecule are critical in defining the habit modifying powers of the dye, and also its solubility in saturated saline solutions. Modified crystal growth is probably most influenced by the adsorption of dye molecules on planes representing edges of the growth layers tending to build up crystal faces. A mechanism for the dye adsorption process depending on the existence of similarities between the patterns of the appropriate polar groups of the dye molecules and the ions of the crystal plane concerned is suggested.

Dyeing Crystals

“…191 In the course of his habit modification work, he discovered several (NH 4 ) 2 SO 4 , NaNO 3 , and KNO 3 DICs. 192 NaNO 3 DICs were earlier prepared by France (section II.E.2). 193 Whetstone developed structural models for DICs on the basis of qualitative linear dichroism.…”

“…Acid fuchsin was especially effective . In the course of his habit modification work, he discovered several (NH 4 ) 2 SO 4 , NaNO 3 , and KNO 3 DICs . NaNO 3 DICs were earlier prepared by France (section II.E.2) …”

Characterization of Habits and Crystalline Modification of Solids and Their Pharmaceutical Applications

“…Sodium chloride, which normally develops only cubic {lo01 faces, develops octahedral {lll) faces when grown in the presence of urea (13,14). Whetstone (15)(16)(17)(18) studied crystal habit modifications due to the addition of impurities as crystal poisons. He found that the crystal habit change by dyes depended on anionic and cationic substituent groups and the nature of substitution.…”