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The term coacervate was coined in 1929 by Dutch chemist Hendrik G. Bungenberg de Jong and Hugo R. Kruyt while studying lyophilic colloidal dispersions. [1] The name is a reference to the clustering of colloidal particles, like bees in a swarm .
Examples are suspensions of rod-like viruses such as the tobacco mosaic virus as well as synthetic macromolecules, such as Li 2 Mo 6 Se 6 nanowire [9] or colloidal suspensions of non-spherical colloidal particles. [10] Cellulose and cellulose derivatives form lyotropic liquid crystal phases as do nanocrystalline (nanocellulose) suspensions. [11]
A colloidal crystal is an ordered array of colloidal particles and fine grained materials analogous to a standard crystal whose repeating subunits are atoms or molecules. [1] A natural example of this phenomenon can be found in the gem opal , where spheres of silica assume a close-packed locally periodic structure under moderate compression .
A colloid is stable if the interaction energy due to attractive forces between the colloidal particles is less than kT, where k is the Boltzmann constant and T is the absolute temperature. If this is the case, then the colloidal particles will repel or only weakly attract each other, and the substance will remain a suspension.
Dispersion is a process by which (in the case of solid dispersing in a liquid) agglomerated particles are separated from each other, and a new interface between the inner surface of the liquid dispersion medium and the surface of the dispersed particles is generated. This process is facilitated by molecular diffusion and convection. [4]
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Diamond also has a very high refractive index and a relatively high optical dispersion. Most natural diamonds have ages between 1 billion and 3.5 billion years. Most were formed at depths between 150 and 250 kilometres (93 and 155 mi) in the Earth's mantle, although a few have come from as deep as 800 kilometres (500 mi). Under high pressure ...
This is not recommended. This involves biting a mineral to see if it’s generally soft or hard. This was used in early gold exploration to tell the difference between pyrite (fools gold, hard) and gold (soft). Several of the minerals where a bite test could be diagnostic contain heavy metals.