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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 highly viscous cubic phase gel made of polysorbate 80, water, and liquid paraffin. Lyotropic liquid crystals result when amphiphiles, which are both hydrophobic and hydrophilic, dissolve into a solution that behaves both like a liquid and a solid crystal. This liquid crystalline mesophase includes everyday mixtures like soap and water. [1] [2]
Liquid crystal (LC) is a state of matter whose properties are between those of conventional liquids and those of solid crystals.For example, a liquid crystal can flow like a liquid, but its molecules may be oriented in a common direction as in a solid.
The liquid crystal properties arise because mesogenic compounds are composed of rigid and flexible parts, which help characterize the order and mobility of its structure. [2] The rigid components align mesogen moieties in one direction and have distinctive shapes that are typically found in the form of rod or disk shapes. [ 2 ]
A crystal is a solid where the atoms form a periodic arrangement. (Quasicrystals are an exception, see below). Not all solids are crystals. For example, when liquid water starts freezing, the phase change begins with small ice crystals that grow until they fuse, forming a polycrystalline structure.
The symmetry properties of crystal are described by the concept of space groups. [1] All possible symmetric arrangements of particles in three-dimensional space may be described by 230 space groups. The crystal structure and symmetry play a critical role in determining many physical properties, such as cleavage , electronic band structure , and ...
For example, highly linear polyethylene can form platelet-like single crystals with a thickness on the order 10–20 nm when crystallized from a dilute solution. The crystal shape can be more complex for other polymers, including hollow pyramids, spirals and multilayer dendritic structures. [2]
Forsterite. In chemistry, isomorphism has meanings both at the level of crystallography and at a molecular level. In crystallography, crystals are isomorphous if they have identical symmetry and if the atomic positions can be described with a set of parameters (unit cell dimensions and fractional coordinates) whose numerical values differ only slightly.