Cadmium sulfoselenide pigments

CdSe forms sohd solutions with CdS which are used as pigments ranging ia color from orange to deep maroon and are called cadmium sulfoselenides. Other uses are ia photocells, rectifiers, lumiaous paiats, and as a mby colorant for glass manufacture. CdSe currentiy sells for 1.50/g as phosphor-grade (99.999% purity) material. 

Pigment Systems. Most of the crystals used for ceramic pigments are complex oxides, owing to the great stability of oxides in molten silicate glasses. Table 3 fists these materials. The one significant exception to the use of oxides is the family of cadmium sulfoselenide red pigments. This family is used because the colors obtained caimot be obtained in oxide systems thus it is necessary to sustain the difficulties of a nonoxide system. 

In an attempt to extend the firing range of these colors, the inclusion pigments (11,17) have been developed. In these pigments cadmium sulfoselenides are incorporated within a clear 2h con lattice. The superior stabiHty of 2h con is thus imparted to the pigment. Colors from yellow to orange-red are available. Deep red is not available, and the purity of these colors is limited. 

Cadmium Sulfoselenide Orange, pigment for plastics, 7 370t... 

Sulfide and sulfoselenide pigments cadmium sulfoselenide cadmium sulfide (Cd, Zn) S ... 

Cadmium red consists of cadmium sulfoselenide [12656-57-4], [58339-34-7], Cd(S,Se), and is formed when sulfur is replaced by selenium in the cadmium sulfide lattice. With increasing selenium content, the color changes to orange, red, and finally dark red. The density of these pigments increases correspondingly from 4.6 to 5.6 g/cm3 and the refractive index from 2.5 to 2.8. The crystals have cubic or spheroidal habits, the prevalent particle size is 0.3-0.4 pm. 

Mercury-cadmium pigments were developed in the early 1950s as a more cost-effective alternative to cadmium sulfoselenides. Mercury replaces part of the cadmium in the cadmium sulfide compound and eliminates the need for selenium. The resulting pigments range from deep orange to a maroon and offer a cleaner, brighter chroma than their cadmium counterparts. Manufacture is the same as for cadmium sulfides, except that mercury salts are added to the cadmium solution that is reacted with the alkali sulfide solution to cause precipitation. 

Cepria and coworkers used the voltammetry of immobilized microparticles to detect and quantify the cadmium pigments (e.g., cadmium sulfide and cadmium sulfoselenide) used in artists paints, as well as in glasses, plastics, ceramics, and enamels [141]. For this, a simple, fast and reliable technique was developed that proved to be especially applicable for valuable art objects, as it was minimally invasive and required only nanogram quantities of material (see also Section 6.4.1). For quantification purposes, an abrasive stripping scan was used from + 0.3 V to —1.0 V, following a 10 s pre-treatment step at —1.5 V. The Cd oxidation peak was evaluated with respect to an internal AgCl calibration standard. 

Cadmium/Mercury Sulfides. One of the major accomplishments of the past 25 years has been the introduction of a series of red and maroon pigments based on mercury and cadmium sulfides (CdS xHgS), to replace the well-known cadmium sulfoselenides. The work was prompted by the increasing shortage of selenium and its ever increasing price. In their search for replacement for the standard... 

Another 25% of the selenium production in 1996 was used in inorganic pigments (principally as cadmium sulfoselenide used in plastics, paints, enamels, inks, mbber, and ceramics), and 10-15% of selenium is used in a broad spectrum of applications including accelerators and vulcanizing agents in mbber production, in stainless steel, and as selenides of refractory metals for use in lubricants. Some of these products may end up as disposed waste. Medical and pharmaceutical uses such as in topical preparations for treatment of dandmff, for... 

Until a few years ago, the red pigment for coloring containers, toys, household wares, plastic crates, etc. was Cadmium Red. This is Cadmium sulfoselenide red, C9Hi3CdN204SSe (CAS 58339-34-7), also known as Pigment Red 108 (see Chemnet 2015). The cadmium compound is now considered environmentally undesirable, so it is being replaced by the non-toxic Cerium(III) sulphide (Cc2S3 CAS 12014-93-6). This compound gives a rich red color and is stable up to 350 °C (Emsley 2001). 

Selenium is involved in some important specialist uses [1], the largest being in the electronics and related industries. Its important use in xerography relates to the photoconductivity of the element. Its asymmetrical conductivity led to the development of surge-resistant rectifiers, while semiconductors, photoelectric cells, and infrared optic materials may all involve selenium. Other relatively major uses are in the manufacture of pink and ted glasses and for heat-resistant red pigments in plastics, enamels, paints, and inks (cadmium sulfoselenide). 

Cadmium sulfide and sulfoselenide pigments have been widely used for their attractive color, high heat resistance and excellent fastness properties. Due to environmental concerns the use of cadmium-based pigments is increasingly restricted. 

The results indicate that the influence of UV stabilisers on heat ageing stability, when used in conjunction with pigments and antioxidants, is extremely difficult to predict in general terms. The results presented for four commercially employed UV stabilisers in Table 9.21 and Figure 9.19 indicate that in some instances UV stabiliser actually appears to enhance the heat ageing resistance, whereas in other instances antagonistic effects are shown, notably when such pigments as ferric oxide and cadmium sulfoselenide are employed. 

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