Zinc Sulfide Cubic

INTRODUCTION This data sheet presents information for single crystal cubic zinc sulfide. 

Specific Heat, (cal/g)/°K 0. 116 where X = A Transmission.Region, (External 

Deutsch, Int. Conf. on the Phys. of Semiconductors, Proc. Exeter, 1962, A. C. Stickland, Ed. Inst, of Phys. Phys. Soc., London, 505-512, (1962). 

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Zinc sulfide, ZnS, sphalerite (zinc blende) zinc sulfide, ZnS, wurtzite zinc selenide, ZnSe zinc telluride, ZnTe, cubic zinc telluride, ZnTe, hexagonal zinc polonide, ZnPo zinc aluminum selenide, ZnAl2Se4 zinc indium selenide, ZnIn2Se4 zinc indium telluride, Znhi2Te4. 

Zinc sulfide is white to gray-white or pale yellow powder. It exists in two crystalline forms, an alpha (wurtzite) and a beta (sphalerite). The wurtzite form has hexagonal crystal structure refractive index 2.356 density 3.98 g/cm3 melts at 1,700°C practically insoluble in water, about 6.9 mg/L insoluble in alkalis soluble in mineral acids. The sphalerite form arranges in cubic crystalline state refractive index 2.368 density 4.102 g/cm changes to alpha form at 1,020°C practically insoluble in water, 6.5 mg/L soluble in mineral... 

The reaction finished within 1 h at 26°C.. They used seed crystals of CdS to promote the uniformity of the final product, and analyzed the growth kinetics using Nielsen s chronomal. The isoelectric point in terms of pH was determined to be 3.7 by electrokinetic measurement. They also prepared zinc sulfide (ZnS polycrystalline spheres), whose isoelectric point in pH was 3.0 (2), lead sulfide (PbS monocrystalline cubic galena) (3), cadmium zinc sulfide (CdS/ZnS amorphous and crystalline spheres) (3), and cadmium lead sulfide (CdS/PbS crystalline polyhedra) (3), in a similar manner. 

Wurtzite structure. Zinc sulfide can also crystallize in a hexagonal form called wurtzite that is formed slightly less exothermically than the cubic zinc blende (sphalerite) modification (Afff = —192.6 and —206.0 kJ mol-1, respectively) and hence is a high temperature polymorph of ZnS. The relationship between the two structures is best described in terms of close packing (Section 4.3) in zinc blende, the anions (or cations) form a cubic close-packed array, whereas in wurtzite they form hexagonal close-packed arrays. This relationship is illustrated in Fig. 4.13 note, however, that this does not represent the actual unit cell of either form. 

FIG. 1.13 Spherical and cubic model particles with crystalline or amorphous microstructure (a) spherical zinc sulfide particles (transmission electron microscopy, TEM, see Section 1.6a.2a) x-ray diffraction studies show that the microstructure of these particles is crystalline (b) cubic lead sulfide particles (scanning electron microscopy, SEM, see Section 1.6a.2a) (c) amorphous spherical particles of manganese (II) phosphate (TEM) and (d) crystalline cubic cadmium carbonate particles (SEM). (Reprinted with permission of Matijevic 1993.)... 

Fia. 7-5.—The arrangement of zinc atoms (small circles) and sulfur atoms (large circles) in sphalerite, the cubic form of zinc sulfide. ... 

The luminescent properties can be influenced by the nature of the activators and coactivators, their concentrations, the composition of the flux, and the firing conditions. In addition, specific substitution of zinc or sulfur in the host lattice by cadmium or selenium is possible, which also influences the luminescent properties. Zinc sulfide is dimorphic and crystallizes below 1020 °C in the cubic zinc-blende structure and above that temperature in the hexagonal wurtzite lattice. When the zinc is replaced by cadmium, the transition temperature is lowered so that the hexagonal modification predominates. Substitution of sulfur by selenium, on the other hand, stabilizes the zinc-blende lattice. 

The zinc blende and wurtzite structures. Zinc sulfide crystallizes in two distinct lattices hexagonal wurtzite (Fig. 4.2a) and cubic zinc blende (Fig. 4.2b). We shall not elaborate upon them now (see page 121), but simply note that in both the coordination number is 4 fbr both cations and anions. The space groups are Ptync and F43m. Can you tell which is which ... 

Zinc sulfide, or sphalerite, crystallizes in the following cubic unit cell ... 

When a zinc sulfide ore, ZnS, is roasted, all the sulfur is released to the atmosphere as SO2. If a maximum of 0.060 mg of SO2 is permitted per cubic meter of air, (a) how many cubic meters of air will be needed for safe disposal of the effluent from the roasting of 1.00 metric tons of zinc sulfide, and (b) how large an area would be covered by such a volume of air if it were 1.00 km high ... 

The structure of cubic zinc sulfide (zinc blende, sphalerite) may be described as a ccp of S atoms, in which half of the tetrahedral sites are filled with Zn atoms the arrangement of the filled sites is such that the coordination numbers of S and Zn are both four, as shown in Fig. 10.1.7. The crystal belongs to space group 7 2 — / 43m. Note that the roles of the Zn and S atoms can be interchanged by a simple translation of the origin. 

Many binary compounds adopt the cubic zinc sulfide structure. Some of these compounds and their unit-cell parameter a values are listed in Table 10.1.6. 

Table 10.1.6. Some binary compounds with cubic zinc sulfide structure and their a...

Weider, D., and U. Sherz (1985). Self-consistent-field cluster calculations of nickel (2 -I-) centers in cubic zinc sulfide, cadmium sulfide, and zinc sele-nide in the CNDO approximation. Phys. Rev. B32, 5273-79. 

Zinc Sulfide. Zinc Blende. SZn mol wt 97.45. S 32,91%. Zn 67.09%. ZnS. Occurs in nature as the minerals wurtzlte (hexagonal, d 4,087) and sphalerite (cubic, d 4.102). Precipitated zinc sulfide ol commerce usually contains 15-20% water of hydration. The dried precipitate may have been heated to 725° in the absence of air to obtain substantial conversion to wurtzite. the form peferred by the pigment industry. 

Zinc sulfide ZnS Wurtzite (m), hexagonal Sphalerite (s), cubic (diamond type)... 

Zinc sulfide exists in two forms, as cubic zinc blende and as hexagonal wurtzite. Of the two modifications, the latter is stable at higher temperatures. The ZnS films obtained by simultaneous vapour condensation of sulphur and zinc onto unheated substrates are crystalline even from 5 nm mass thickness. However, the diffraction pattern shows that these small, isolated, three-dimensional ZnS microcrystals contain a large number of stacking faults in all three spatial coordinates. In thicker films (from about 20 nm), the diffraction pattern shows better-ordered crystallites of the zinc blende type. ZnS films deposited at normal incidence have a clearly distinct <111> growth texture becoming noticeable from about 100 nm, as can be seen in Fig. 2 [17b],... 

In fact, trigonal holes are so small that they are never occupied in binary ionic compounds. Whether the tetrahedral or octahedral holes in a given binary ionic solid are occupied depends mainly on the relative sizes of the anion and cation. For example, in zinc sulfide the ions (ionic radius = 180 pm) are arranged in a cubic closest packed structure with the smaller ions (ionic radius = 70 pm) in the tetrahedral holes. The locations of the tetrahedral holes in the face-centered cubic unit cell of the ccp structure are shown in Fig. 10.36(a). Note from this figure that there are eight tetrahedral holes in the unit cell. Also recall from the discussion in Section 10.4 that there are four net spheres in the face-centered cubic unit cell. Thus there are twice as many tetrahedral holes as packed anions in the closest packed structure. Zinc sulfide must have the same number of S ions and Zn ions to achieve electrical neutrality. Thus in the zinc sulfide structure only half the tetrahedral holes contain Zn ions, as shown in Fig. 10.36(c). 

Krunks et al. [119] studied zinc thiocarbamide chloride as a single-source precursor for obtaining thin films of zinc sulfide by spray pyrolysis. By heating this compound to 1200 C, they demonstrated that cubic ZnS (sphalerite) forms below 300 °C and stays in this form until 760 C, when it transforms to hexagonal ZnS (wurtzite). 

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