Name | Cadmium sulfide |
Synonyms | thioxocadmium Cadmium Yellow Cadmium sulfide cadmium sulphide Cadmiumsulfideyelloworangepowder |
CAS | 1306-23-6 |
EINECS | 215-147-8 |
InChI | InChI=1/Cd.S/q+2;-2 |
Molecular Formula | CdS |
Molar Mass | 144.476 |
Density | 4.82 g/mL at 25 °C(lit.) |
Melting Point | 980°C (subl.) |
Boling Point | 980°C (estimate) |
Flash Point | 4℃ |
Water Solubility | insoluble |
Appearance | Morphological powder |
Color | Yellow to orange |
Merck | 14,1628 |
Storage Condition | 2-8°C |
Use | Used for enamel, glass, ceramic, plastic, Paint coloring |
Hazard Symbols | T - Toxic N - Dangerous for the environment |
Risk Codes | R22 - Harmful if swallowed R45 - May cause cancer R53 - May cause long-term adverse effects in the aquatic environment R62 - Possible risk of impaired fertility R63 - Possible risk of harm to the unborn child R68 - Possible risk of irreversible effects |
Safety Description | S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S53 - Avoid exposure - obtain special instructions before use. S61 - Avoid release to the environment. Refer to special instructions / safety data sheets. |
UN IDs | UN 3077 |
WGK Germany | 3 |
RTECS | EV3150000 |
TSCA | Yes |
Hazard Class | 6.1 |
Packing Group | III |
Downstream Products | Chromium(III) oxide Pigment yellow 37 (C.I. 77199) |
Solubility | Soluble in acid, very slightly soluble in ammonium hydroxide. |
Specific gravity | 4.82 |
crystal structure | Cubic, Sphalerite Structure - Space Group F(-4)3m |
Ksp precipitation equilibrium constant | pKsp: 26.1 |
Exposure Limits | ACGIH: TWA 0.01 mg/m3; TWA 0.002 mg/m3 NIOSH: IDLH 9 mg/m3 |
EPA chemical information | Cadmium sulfide (1306-23-6) |
overview
Cadmium sulfide (English cadmium sulfide) molecular formula CdS, molecular weight 144.46, is an N-type photoconductive semiconductor material. It belongs to group II-VI compound semiconductor. There are crystals and amorphous objects. There are two kinds of crystals: α-type, lemon yellow powder, density 3.91~4.15;β-type, orange powder, density 4.48~4.51. In nature, there are sulfur-cadmium ore, hexagonal crystals, and the density is 4.82. Can sublimate in nitrogen. Slightly toxic, non-radioactive, slightly soluble in water and ethanol, soluble in acid, easily soluble in ammonia. The forbidden band width is 2.41 electron volts, and the mobility of electrons and holes are 2 × 10-2 and 2 × 10-3 m2/volt · sec, respectively, and the relative dielectric constant is 11.6. Used for making fireworks, glass glaze, enamel, luminescent materials, and used as pigments (cadmium yellow and cadmium red) for paints, paper, rubber and glass. High purity is a good semiconductor, which is obtained by passing hydrogen sulfide into cadmium hydrochloric acid solution to generate precipitation, which is filtered, washed and dried. The solubility product of cadmium sulfide is 3.6 × 10-29.
Cadmium sulfide photoconductor has the outstanding advantages of large potential difference of electrostatic latent image and large contrast of copied image. Because the surface layer is added with an insulating film, the wear resistance of the photoconductor is good. Due to its high sensitivity to light, it can be used on machines of various speeds. However, the insulating film on the surface of the light conductor has some influence on the resolution of the image. Cadmium sulfide is very sensitive to temperature and is afraid of moisture. Because there is no protective film on its surface, it is not good for the operator's body and is not conducive to the treatment of waste light conductors. Therefore, it is less and less used at present.
Cadmium sulfide is not easy to be made into single crystal, so although it has entered the practical stage earlier than germanium, silicon and gallium arsenide, the research on it is still not in-depth, and its polycrystalline sintered body and thin film are mostly used. Cadmium sulfide is an N-type photoconductive device material with high sensitivity, and it is also a piezoelectric device material. The solid solution with zinc sulfide can be made into a laser with a laser wavelength of (3300~4900)× 10-10 meters; the solid solution with cadmium selenide can be made into a laser with a laser wavelength of (4900~6750)× 10-10 meters; Although the efficiency of thin-film heterojunction solar cells made of cadmium telluride is lower than 10%, they are cheap and can be made into large-area devices.
Solubility in water (g/100ml)
Dissolved grams per 100 ml of water:
1.292×10-12/20℃
Cadmium selenide photoresistor
ultraviolet photoresistors: sensitive to ultraviolet rays, including cadmium sulfide, cadmium selenide photoresistors, etc., used to detect ultraviolet rays.
Visible light photoresistors: including selenium, cadmium sulfide, cadmium selenide, cadmium telluride, gallium arsenide, silicon, germanium, zinc sulfide photoresistors, etc. Mainly used in various photoelectric control systems, such as photoelectric automatic switch portals, automatic on and off of navigation lights, street lights and other lighting systems, automatic water supply and automatic water stop devices, mechanical automatic protection devices and "position detectors", extremely thin parts Thickness detector, camera automatic exposure device, photoelectric counter, smoke alarm, photoelectric tracking system, etc.
Preparation method
cadmium ore is leached with sulfuric acid to form cadmium sulfate. adjust PH = about 3.5 and precipitate with sodium sulfide. the PH cannot be too low.
Production method
1. CdS precipitate of cubic crystals can be obtained by passing H2S gas into a hot solution of cadmium perchlorate acidified with a little perchloric acid or an aqueous solution of cadmium sulfate acidified with sulfuric acid.
2. After cadmium chloride is treated with hydrochloric acid to be acidic, thioacetamide is added, and the solution is heated to produce precipitation. The CdS obtained by this method is doped with halide ions, which cannot be removed in the process of washing products. The resulting CdS is a hexagonal crystal containing halogen ions.
category
Toxic substances
Toxicity classification
Poisoning
Acute toxicity
oral-rat LD50: 7080 mg/kg; Oral-mouse LD50: 1166 mg/kg
flammability hazard characteristics
Thermal decomposition discharges toxic sulfur oxides and cadmium-containing smoke
storage and transportation features
Warehouse low temperature ventilation and drying
Fire extinguishing agent
Water, carbon dioxide, foam, dry powder
occupational standards
TWA 0.05 mg (cadmium)/m3
toxic substance data | 1306-23-6(Hazardous Substances Data) |