Sphalerite type

Ga2Se3 [12024-24-7] 1005-1010 monoclinic, B2/m (superstmcture of deformed blend type) cubic by quenching of Hquid compound (disordered sphalerite type) 4.95... 

The structure of zunyite is shown in Pig. 6. It may be considered as a sphalerite-type arrangement of the tetrahedral and octahedral groups, the group of twelve octahedra (Fig. 4) replacing Zn and the group of five tetrahedra (Pig. 2) replacing S. The interatomic distances, which... 

The structural relationship between diamond and sphalerite types (see 7.4.2.3), for instance, may be described as lattice equivalent, t, in the form ... 

Diamond type (space group Fd3m, N. 227) — 12 — sphalerite type (space group F43m, N. 216). 

Considering, for instance, the cF8-ZnS-sphalerite type structure (containing 4 Zn + 4 S in the unit cell) the space-filling (Parthe 1964) can be given by ... 

This equation describes the middle section (0.225 < e < 4.44) of the space-filling curve for the sphalerite type structure plotted (with log scales) in Fig. 4.22. 

The diamond structure, see Fig. 7.14 below, is a 3D network in which every atom is surrounded tetrahedrally by four neighbours. The eight atoms in the unit cell may be considered as forming two interpenetrating face-centred cubic networks. If the two networks are occupied by different atoms, the derivative cF8-ZnS (sphalerite) type structure is obtained. As a further derivative structure, the tI16-FeCuS2 type structure can be mentioned. These are all examples of a family of tetrahedral structures which have been described by Parthe (1964). 

Figure 7.23. Section sequence parallel to the base plane of the cF8-ZnS sphalerite-type structure.

In xylene, 15 nm InAs nanocrystallites (Figure 7.10B) were prepared by zinc coreduction of InCl3-4H20 and ASCI3 at 160 °C [43]. The XRD pattern indicates that the products were sphalerite-type cubic InAs (Figure 7.10A). As shown in Reactions (5)-(8), a trace amount of water resulting from the reactants may be helpful to the process. 

The XRD pattern (Figure 7.11(a)) indicates that the product is sphalerite-type cubic InP. The TEM images (Figure 7.11(b)) show that the products are 9 nm spherical... 

As a result of using organic phosphorus starting material, crystal growth was appropriately controlled. Nanowires of sphalerite-type GaP and InP (Figure 7.13) were prepared, suggesting a promising method for the solvothermal synthesis of one-dimensional III-V nanocrystallites. 

In a temperature domain below 100K, a temperature decrease can result in an increase of the lattice spacing, as in silicon or in some sphalerite-type crystals. 

In the vicinity of the VB maximum at k = 0, the expressions for the constant-energy surfaces of the VB electrons in the highest-energy band of the diamond- or sphalerite-type crystals are usually given as functions of three parameters A, B and C. These maxima are warped spheres in the k-space given by ... 

Fig. 3.10. Calculated direct excitonic gap of wurtzite-type (upper line) and sphalerite-type (lower line) CdS spherical clusters as a function of the cluster radii, compared with the experimental results. Full diamonds and circles are for sphalerite-and wurtzite-type clusters, respectively. The exciton binding energy in bulk CdS is 0.03eV (after [94]). Copyright 1996, American Institute of Physics...

The phase diagram of CuaTe-GagTeg has been determined. A compound CuaGa4Te7 is formed which is a defect sphalerite-type semiconductor (energy gap 1.08 0.05 eV). 

A different kind of change in cation occurs in the common mineral chalcopyrite. The formula of chalcopyrite is usually given as CuFeSa, from which we can assume that there are two cations, Cu " and Fe and one anion, (of course, there are two anions for every copper or iron cation). The anion packing is cubic closest packing, giving a sphalerite type structure. 

The class of diampnd-like semiconductors is not restricted to phases with a valence electron concentration of n = 4 per atom. This was shown by one of the authors, ff n > 4, phases are obtained which possess a sphalerite-type structure. At the same time, there are more anions than cations and some of the cation sites in the lattice are therefore unoccupied. In complex systems (with more than two components) phases can be obtained with continuously varying valence electron concentrations and numbers of cation defects. Defect diamond-like phases frequently have structures in which the atoms and defects have a certain ordering. 

Valence compounds, like elements, satisfy the Hume-Rothery rule, as can be seen by calculating the average coordination number for these compounds. At the same time, they retain the tetrahedral distribution of the atoms, i.e., the tetrahedral bonds. The structure of defect diamond-like phases has been studied in some detail but corresponding data for excess phases are not available. The problem of the change in the structure of excess phases with varying valence electron concentration is more complicated since it is neither immediately apparent nor known how a sphalerite-type structure is transformed into a defect antifluorite-type structure. 

The delta-function deconvolution method (FFT) was used to improve the spectral resolution and to remove the plural scattering effect at the core-loss edge in electron energy-loss spectroscopy (EELS). The zero-loss peak (used as an instrumental resolution function) works as a nonattenuation high-pass filter in this technique [17]. Reflectance spectra in the vacuum ultraviolet of microcrystalline 3-BN, prepared by plasma CVD (chemical vapor deposition), and of sintered (3-BN measured with synchrotron radiation in the energy range from 5 to 25 eV, show reflectance peaks near 11.4 and 14 eV and a broad peak near 18 eV. The peaks at 11.4 and 14.0 eV are assigned to the E and E2 peaks of the sphalerite-type semiconductor [18]. 

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