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PHASE CHANGE. "Nucleation is one of the two major mechanisms of the first order phase transition, the process of generating a new phase from an old phase whose free energy has become higher than that of the emerging new phase. Nucleation occurs via the formation of small embryos of the new phase inside the large volume of the old phase. Another prominent feature of nucleation is metastability of the old phase, i.e., the transformation requires passage over a free energy barrier." https://lnkd.in/eVX4ANS View in LinkedIn

CRITICAL NUCLEUS. "The structure of the assembly of molecules or ions which we call a critical nucleus is not known, and it is too small to observe directly. It could be a miniature crystal, nearly perfect in form. On the other hand, it could be a rather diffuse body with molecules or solvated ions in a state not too different from that in the bulk fluid, with no clearly defined surface." https://lnkd.in/eTDpY_Q View in LinkedIn

STABLE LATTICE. "Exactly how a stable crystal nucleus is formed within a homogeneous fluid is not known with any degree of certainty. The formation of crystal nuclei is an even more difficult process to envisage. Not only have the constituent molecules to coagulate, resisting the tendency to redissolve, but they also have to become orientated into a fixed lattice." https://lnkd.in/eTDpY_Q View in LinkedIn

CRYSTAL NUCLEATION "is the initiation of a phase change in a small region, such as the formation of a solid crystal from a liquid solution. It is a consequence of rapid local fluctuations on a molecular scale in a homogeneous phase that is in a state of metastable equilibrium." https://lnkd.in/eMnXY6A View in LinkedIn

"THE BIRTH OF A CRYSTAL —the so-called nucleation process—is one of the most fascinating problems in protein crystallization...the mechanisms leading to the formation of clusters of molecules displaying translational and rotational order have their own rules completely different from those of crystal growth." https://lnkd.in/eDMAEEh View in LinkedIn

ORDER FROM DISORDER. "Crystals are paradigmatic examples of long-range-ordered structures obtained through a self-assembly process via a first-order phase transition that starts from a disordered state, such as a liquid or a gas. The initial stage of a crystallization process, nucleation, is the fundamental and yet not well understood phenomenon leading to the formation of an embryonic structure with crystal-like properties." https://lnkd.in/enRrMvs View in LinkedIn

FORBIDDEN CRYSTAL SYMMETRY, by Oxford's eccentric and brilliant Sir Roger Penrose. While rigorous mathematical theory suggests that crystal symmetry can only go to 6-fold, symmetry forms up to 12-fold have been described. And, 5-fold and 12-fold crystal forms do occur in nature. https://lnkd.in/eHBgHXN View in LinkedIn

"FLEXICRYSTALLOGRAPHY structure and symmetry properties of about 50 periodic minimal-energy surfaces, and how they allow one to transcend the boundary of traditional crystallography and the 230 classic space groups, to encompass periodic curved surfaces found in soft structures such as liquid crystal mesophases and biological assemblies." New thinking. https://lnkd.in/eY-FGha View in LinkedIn

CLASSICAL CRYSTAL UNIVERSE. "By considering what type of symmetry a mineral species possesses, the species may be categorized as a member of one of six crystal systems and one of thirty-two crystal classes." Old thinking. https://lnkd.in/eBPA9ua View in LinkedIn

SELF-ORGANIZATION. "Atoms self-organize in crystals, most of the time. The crystalline lattice, is a periodic array of the atoms. When the solid is not crystalline, it is called amorphous. Examples of crystalline solids are metals, diamond and other precious stones, ice, graphite. Examples of amorphous solids are glass, amorphous carbon (a-C), amorphous Si, most plastics." https://lnkd.in/epuMuJA View in LinkedIn