Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Crystals scalenohedral

The [hkil] faces, which determine the dog-tooth (scalenohedral) Habitus of calcite crystals, and the prismatic [hkil] face of tourmaline crystals show striations only, never step patterns. These faces are S faces, by PBC analysis, and they appear due to a pile up of steps developing on the neighboring F faces. Yet they develop as large as those that determine the Habitus. [Pg.90]

Figure 11.5. Three examples showing different Habitus of later-grown calcite crystals preferentially nucleated on the edges and corners of earlier-formed calcite crystal. Changes in Habitus depending on crystallization stages or growth temperatures are indicated [3]. (a) Earlier-formed hexagonal prism (A) and later-formed scalenohedral crystal (B). (b) Earlier-formed hexagonal prism (b) and later-formed thicker crystal (a), (c) The shaded area shows an earlier-formed rhombohedral crystal, and the remaining area represents later-formed scalenohedral crystals. Figure 11.5. Three examples showing different Habitus of later-grown calcite crystals preferentially nucleated on the edges and corners of earlier-formed calcite crystal. Changes in Habitus depending on crystallization stages or growth temperatures are indicated [3]. (a) Earlier-formed hexagonal prism (A) and later-formed scalenohedral crystal (B). (b) Earlier-formed hexagonal prism (b) and later-formed thicker crystal (a), (c) The shaded area shows an earlier-formed rhombohedral crystal, and the remaining area represents later-formed scalenohedral crystals.
The dihydrate, K2Pt(CNSe)8.2H20, yields trigonal scalenohedral crystals.7... [Pg.328]

Figure 2.14. Different crystalline forms of calcium carbonate. Courtesy of Omya/Pliiss-Staufer AG (micrographs of crystals), Solvay, GmbH, Rheinberg, Germany (crystal stmcture and micrographs of Socal trigonal-scalenohedral calcite), and ECC International Ltd., St. Austell, UK (rhombohedral calcite and aragonite). Figure 2.14. Different crystalline forms of calcium carbonate. Courtesy of Omya/Pliiss-Staufer AG (micrographs of crystals), Solvay, GmbH, Rheinberg, Germany (crystal stmcture and micrographs of Socal trigonal-scalenohedral calcite), and ECC International Ltd., St. Austell, UK (rhombohedral calcite and aragonite).
The process is complex and involves simultaneous dissolution of calcium hydroxide and carbon dioxide, and crystallisation of calcium carbonate. Carbonation is generally carried out in a series of reactors under closely controlled pH, temperature and degree of supersaturation, to produce the required PCC morphology and particle size distribution (see section 31.2.3). Crystallisation can occur on the surface of the calcium hydroxide particles (producing scalenohedral crystals), in the aqueous phase (producing rhombohedral crystals) and at the gas-liquid interface. [Pg.352]

Calcined kaolin, scalenohedral PCC, aragonitic PCC and amorphous silicates are examples of aggregated fillers, i.e. these products consist of crystals which are synthetically clustered into repetitive shapes of similar size throughout the... [Pg.128]

See other pages where Crystals scalenohedral is mentioned: [Pg.80]    [Pg.231]    [Pg.270]    [Pg.271]    [Pg.272]    [Pg.34]    [Pg.249]    [Pg.250]    [Pg.842]    [Pg.52]    [Pg.9]    [Pg.199]    [Pg.842]    [Pg.843]    [Pg.21]    [Pg.21]    [Pg.123]    [Pg.292]    [Pg.294]    [Pg.412]    [Pg.483]    [Pg.72]    [Pg.807]    [Pg.74]    [Pg.477]    [Pg.334]   
See also in sourсe #XX -- [ Pg.371 ]



SEARCH



© 2024 chempedia.info