Zinc sulfide
Left: sphalerite ( cubic); right: wurtzite ( hexagonal) __ Zn2 __ S2
- Zinc (II ) sulphide
- Sphalerite
- Sphalerite
- Wurtzite
- C. I. Pigment White 7
Yellow, odorless powder
Fixed
4.01 g · cm -3
1185 ° C
- Practically insoluble in water
- Soluble in dilute mineral acids
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Zinc sulfide (more specifically zinc (II ) sulphide, ZnS molecular formula ) is the zinc salt of hydrogen sulphide. It occurs in nature as the mineral sphalerite cubic ( zinc blende ) and hexagonal wurtzite before and can be mined. Both sphalerite and the wurtzite zinc ions are tetrahedrally surrounded by four sulfide ions and vice versa. Both crystal structures are prototypes for a number of compounds. Wurtzite, the high-temperature modification dar. zinc sulfide is a II -VI compound semiconductors ( EG = 3.54 eV at room temperature).
Production
Zinc sulfide may be prepared by oxidation of zinc with sulfur:
It is also produced in the reaction of aqueous solutions of zinc salts with ammonium sulfide solution as a white to pale yellow amorphous precipitate.
Production is also possible by the reaction of a zinc sulphate solution with hydrogen sulfide with the addition of ammonium acetate
Or the reaction of zinc oxide and sulfur in an ammoniacal medium.
Use
With Al3 - and Cu ions doped zinc sulfide shows luminescence and is used for light screens in picture tubes, Magic eyes and luminous dials of watches. Also, it comes in electroluminescent films for application. Alternatively, doping is possible with silver ions.
In painting, it is used together with barium sulfate as a white pigment, a co-precipitated form is called lithopone. A disadvantage of the application as a pigment is the limited resistance of ZnS especially for outdoor applications. Oxygen oxidizes ZnS slowly soluble zinc sulfate.
Because of its high refractive index of 2.37 thin, vacuum-deposited ZnS films are used for compensation of optical components.