Crystal structures hexagonal

STRUCTURE. CdS Can exist in three different crystal structures hexagonal (wurtzite), cubic (zincblende)— both tetrahedrally coordinated and cubic (rock-salt), which is sixfold coordinated. Except in a few cases, the rocksalt modification of CdS has been observed only at very high pressures CD films of this phase have never been reported. The other two phases have been reported to occur in CD films under various conditions. The wurtzite phase is thermodynamically slightly more stable, and invariably forms if the zincblende phase is heated above 300-400°C. The low-temperature CD method therefore can allow the formation of the zincblende phase, and this phase is commonly obtained in CD CdS films. Very often, a mixture of wurtzite and zincblende phases has been reported in the literature. There are many variables that affect the crystal structure, including the nature of the complex, the substrate, and sometimes even stirring. 

PORE CHANNEL / CRYSTAL STRUCTURE Hexagonal, lamellar, cubic (ordered) Wormhole (disordered)... 

Crystal Structure Hexagonal (usual form) or Rhombohedral. Each Mo atom is surrounded by a trigonal prism of S atoms... 

Gray-blue, brittle homogeneous contains 33 and 35 atom% Te. M.p. about 900°C. d 7.338. Crystal structure hexagonal (special type), defect lattice at Cu <3 Te. 

Silvery, shiny material with metallic appearance. Insoluble in nitric acid. d 7.147. Crystal structure hexagonal. Heat of formation (25°C) — 36.0 kcal./mole. 

Light yellow, finely grained powder, d (pycn.) 7.64, d (x-ray) 7.66. Crystal structure hexagonal (space group D h) ... 

Black-gray powder, d 7.66. Unaffected by moisture and O3. Dissolved slowly by dil. mineral acids in the cold, rapidly by cone. HCl and cone. HNO3. Dissolved rapidly by all hot acids. Not attacked by aqueous NaOH. Crystal structure hexagonal close packing of Ni atoms, oriented incorporation of N. 

Gray-black powder, di 7.97. Heat of formation —9.2kcal. per mole. Decomposed at room temperature by cone, and dil. HCl precipitation of C does not occur (see FegC). Soluble in dil. HNO3 dil. H3SO4 causes separation of C. Stable at temperatures up to 380-400°C. Crystal structure hexagonal close packing of Ni atoms. 

Crystal Structure. Hexagonal boron nitride is composed of series of stacked parallel layer planes shown schematically in Fig. 12.2. In this figure, the circles showing the position of the nitrogen and boron atoms do not represent the actual size of these atoms. In fact, each atom contacts its neighbors. 

Self-organization of ion pairs into a mesophase with usually a liquid-crystal structure (hexagonal, lamellar, or cubic), the nature of which depends on the composition of the mixture, the pH, the temperature, and the reaction time. 

The hydrocarbon chain-packing modes are usually described by means of a subcell, which gives the symmetry relations between equivalent positions in one chain and its neighbors [9,10]. Four types of subcells have been identified (1) The planes contain parallel hydrocarbon chains, (2) the chains are perpendicular to each other, (3) the chain axes are crossed, and (4) the chains are packed in a hexagonal lattice. By lateral repetition of the subcell, the entire structure of the chain region is obtained. Structural analysis of normal paraffins with more than nine carbon atoms in the chain revealed mainly four possible distinct crystal structures hexagonal, triclinic, monoclinic, and orthorhombic [11]. 

Particle size, pm 3-200 Crystal structure hexagonal Spec, surface area, m /g 0.5-25 ... 

Particle shape irregular or tubular Crystal structure hexagonal, hollow, single wall multiwall fibers ... 

Crystal structure, hexagonal close-packed (hep) A crystal sfructure where in alternate layers of atoms the atoms in one layer lie at the vertices of a series of equilateral triangles in the atomic plane, and the atoms in the layer lie directly above the center of the triangles in the atomic plane of the next layer. Example Beryllium. 

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