A phosphor is a substance that exhibits the phenomenon of luminescence; it emits light when exposed to some type of radiant energy. The term is used both for fluorescent or phosphorescent substances which glow on exposure to ultraviolet or visible light, and cathodoluminescent substances which glow when struck by an electron beam in a cathode-ray tube.
Sphalerite is a sulfide mineral with the chemical formula (Zn,Fe)S. It is the most important ore of zinc. Sphalerite is found in a variety of deposit types, but it is primarily in sedimentary exhalative, Mississippi-Valley type, and volcanogenic massive sulfide deposits. It is found in association with galena, chalcopyrite, pyrite, calcite, dolomite, quartz, rhodochrosite, and fluorite.
Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. Sulfide also refers to chemical compounds large families of inorganic and organic compounds, e.g. lead sulfide and dimethyl sulfide. Hydrogen sulfide (H2S) and bisulfide (SH−) are the conjugate acids of sulfide.
Epitaxy refers to a type of crystal growth or material deposition in which new crystalline layers are formed with one or more well-defined orientations with respect to the crystalline seed layer. The deposited crystalline film is called an epitaxial film or epitaxial layer. The relative orientation(s) of the epitaxial layer to the seed layer is defined in terms of the orientation of the crystal lattice of each material. For most epitaxial growths, the new layer is usually crystalline and each crystallographic domain of the overlayer must have a well-defined orientation relative to the substrate crystal structure. Epitaxy can involve single-crystal structures, although grain-to-grain epitaxy has been observed in granular films. For most technological applications, single domain epitaxy, which is the growth of an overlayer crystal with one well-defined orientation with respect to the substrate crystal, is preferred. Epitaxy can also play an important role while growing superlattice structures.
Zinc oxide is an inorganic compound with the formula ZnO. It is a white powder that is insoluble in water. ZnO is used as an additive in numerous materials and products including cosmetics, food supplements, rubbers, plastics, ceramics, glass, cement, lubricants, paints, sunscreens, ointments, adhesives, sealants, pigments, foods, batteries, ferrites, fire retardants, semi conductors, and first-aid tapes. Although it occurs naturally as the mineral zincite, most zinc oxide is produced synthetically.
Zinc sulfide is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various impurities, the pure material is white, and it is widely used as a pigment. In its dense synthetic form, zinc sulfide can be transparent, and it is used as a window for visible optics and infrared optics.
Cadmium sulfide is the inorganic compound with the formula CdS. Cadmium sulfide is a yellow salt. It occurs in nature with two different crystal structures as the rare minerals greenockite and hawleyite, but is more prevalent as an impurity substituent in the similarly structured zinc ores sphalerite and wurtzite, 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. Its vivid yellow color led to its adoption as a pigment for the yellow paint "cadmium yellow" in the 18th century.
Wurtzite is a zinc and iron sulfide mineral with the chemical formula (Zn,Fe)S, a less frequently encountered structural polymorph form of sphalerite. The iron content is variable up to eight percent. It is trimorphous with matraite and sphalerite.
Sulfate-reducing microorganisms (SRM) or sulfate-reducing prokaryotes (SRP) are a group composed of sulfate-reducing bacteria (SRB) and sulfate-reducing archaea (SRA), both of which can perform anaerobic respiration utilizing sulfate (SO2−
4) as terminal electron acceptor, reducing it to hydrogen sulfide (H2S). Therefore, these sulfidogenic microorganisms "breathe" sulfate rather than molecular oxygen (O2), which is the terminal electron acceptor reduced to water (H2O) in aerobic respiration.
Sodium hydrosulfide is the chemical compound with the formula NaSH. This compound is the product of the half-neutralization of hydrogen sulfide with sodium hydroxide (NaOH). NaSH and sodium sulfide are used industrially, often for similar purposes. Solid NaSH is colorless. The solid has an odor of H2S owing to hydrolysis by atmospheric moisture. In contrast with sodium sulfide, which is insoluble in organic solvents, NaSH, being a 1:1 electrolyte, is more soluble.
Sulfur water is a condition where water is exposed to hydrogen sulfide gas, giving a distinct "rotten egg" smell. This condition has different purposes in culture varying to health and implications to plumbing.
Aluminium sulfide is a chemical compound with the formula Al2S3. This colorless species has an interesting structural chemistry, existing in several forms. The material is sensitive to moisture, hydrolyzing to hydrated aluminum oxides/hydroxides. This can begin when the sulfide is exposed to the atmosphere. The hydrolysis reaction generates gaseous hydrogen sulfide (H2S).
Acid sulfate soils are naturally occurring soils, sediments or organic substrates that are formed under waterlogged conditions. These soils contain iron sulfide minerals and/or their oxidation products. In an undisturbed state below the water table, acid sulfate soils are benign. However, if the soils are drained, excavated or otherwise exposed to air, the sulfides react with oxygen to form sulfuric acid.
Tutton's salts are a family of salts with the formula M2M'(SO4)2(H2O)6 (sulfates) or M2M'(SeO4)2(H2O)6 (selenates). These materials are double salts, which means that they contain two different cations, M+ and M'2+ crystallized in the same regular ionic lattice. The univalent cation can be potassium, rubidium, cesium, ammonium (NH4), deuterated ammonium (ND4) or thallium. Sodium or lithium ions are too small. The divalent cation can be magnesium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc or cadmium. In addition to sulfate and selenate, the divalent anion can be chromate (CrO42−), tetrafluoroberyllate (BeF42−), hydrogenphosphate (HPO42−) or monofluorophosphate (PO3F2−). Tutton's salts crystallize in the monoclinic space group P21/a. The robustness is the result of the complementary hydrogen-bonding between the tetrahedral anions and cations as well their interactions with the metal aquo complex [M(H2O)6]2+.
Zinc compounds are chemical compounds containing the element zinc which is a member of the group 12 of the periodic table. The oxidation state of zinc in most compounds is the group oxidation state of +2. Zinc may be classified as a post-transition main group element with zinc(II). Zinc compounds are noteworthy for their nondescript appearance and behavior: they are generally colorless, do not readily engage in redox reactions, and generally adopt symmetrical structures.
Magnesium monohydride is a molecular gas with formula MgH that exists at high temperatures, such as the atmospheres of the Sun and stars. It was originally known as magnesium hydride, although that name is now more commonly used when referring to the similar chemical magnesium dihydride.
Evolution of metal ions in biological systems refers to the incorporation of metallic ions into living organisms and how it has changed over time. Metal ions have been associated with biological systems for billions of years, but only in the last century have scientists began to truly appreciate the scale of their influence. Major and minor metal ions have become aligned with living organisms through the interplay of biogeochemical weathering and metabolic pathways involving the products of that weathering. The associated complexes have evolved over time.
Sulfoxylic acid (H2SO2) (also known as hyposulfurous acid or sulfur dihydroxide) is an unstable oxoacid of sulfur in an intermediate oxidation state between hydrogen sulfide and dithionous acid. It consists of two hydroxy groups attached to a sulfur atom. Sulfoxylic acid contains sulfur in an oxidation state of +2. Sulfur monoxide (SO) can be considered as a theoretical anhydride for sulfoxylic acid, but it is not actually known to react with water.
