Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
with the formula CdS. Cadmium sulfide is a yellow solid. It occurs in nature with two different crystal structures as the rare minerals greenockite
Greenockite is a rare cadmium mineral that consists of cadmium sulfide, CdS, in crystalline form. Greenockite crystallizes in the hexagonal system. It occurs as massive encrustations and as six-sided pyramidal crystals which vary in color from a honey yellow through shades of red to brown...
Hawleyite is a rare sulfide mineral in the sphalerite group, dimorphous and easily confused with greenockite. Chemically, it is a cadmium sulfide, and occurs as a bright yellow coating on sphalerite or siderite in vugs, deposited by meteoric waters....
, but is more prevalent as an impurity substituent in the similarly structured zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
Sphalerite is a mineral that is the chief ore of zinc. It consists largely of zinc sulfide in crystalline form but almost always contains variable iron. When iron content is high it is an opaque black variety, marmatite. It is usually found in association with galena, pyrite, and other sulfides...
Wurtzite is a zinc iron sulfide mineral a less frequently encountered mineral form of sphalerite. The iron content is variable up to eight percent. It is trimorphous with matraite and sphalerite....
, which are the major economic sources of cadmium. As a compound that is easy to isolate and purify, it is the principal source of cadmium for all commercial applications.
Cadmium sulfide can be prepared by the precipitation from soluble cadmium(II) salts with sulfide ion and this has been used in the past for gravimetric analysis and qualitative inorganic analysis
Qualitative inorganic analysis
Classical qualitative inorganic analysis is a method of analytical chemistry which seeks to find elemental composition of inorganic compounds. It is mainly focused on detecting ions in an aqueous solution, so that materials in other forms may need to be brought into this state before using standard...
Pigment production usually involves the precipitation of CdS, the washing of the precipitate to remove soluble cadmium salts followed by calcination (roasting) to convert it to the hexagonal form followed by milling to produce a powder.