Solid state synthesis crystals

Traditional solid-state synthesis involves the direct reaction of stoichiometric quantities of pure elements and precursors in the solid state, at relatively high temperatures (ca. 1,000 °C). Briefly, reactants are measured out in a specific ratio, ground together, pressed into a pellet, and heated in order to facilitate interdiffusion and compound formation. The products are often in powdery and multiphase form, and prolonged annealing is necessary in order to manufacture larger crystals and pure end-products. In this manner, thermodynamically stable products under the reaction conditions are obtained, while rational design of desired products is limited, as little, if any, control is possible over the formation of metastable intermediates. ... 

Crystal Growth and Solid State Synthesis of Oxide Superconductors... 

The nanocrystals of such type form in various liquid media, such as organic solution [77, 81] or the softened quasi-liquid glass [82, 83], where there are no steric hindrances for the growth of equilibrium crystals without surface defects. At the same time, barriers for aggregation of clusters or atoms to metal nanocrystals in solid system that arises during the cryochemical solid-state synthesis favor the formation of crystals with structural defects,... 

The main difference between the solid-state reaction synthesis route and hydro(sol-vo)thermal synthesis route lies in reactivity , which is reflected in reaction mechanisms. Reactions in solid-state synthesis depend on the diffusion of the reactants at the interface, whereas individual reactant molecules existing in the liquid phase can react with each other in hydro(solvo)thermal synthesis. Variation in the reaction mechanism leads to the formation of different structures from the same or similar starting materials. In addition, even the same material that can be obtained by both preparation routes can have totally different morphology and properties due to different formation mechanisms. For instance, perfect single crystals can usually be formed from liquid-phase synthesis, while being very difficult to obtain in solid-state synthesis. 

C. L. Tang, H. H. Ni, and X. L. Jin, Solid-state synthesis at low-heating temperature and crystal structure... 

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