(1) During primary sulphate assimilation in chloroplasts, sulphate is reduced via sulphite to the organic sulphide which is used for cysteine biosynthesis.(2) Although an amino acid acceptor of sulphide is necessary for sulphate assimilation, only little attention was paid to the regulation of S assimilation by carbon metabolites.(3) The latter mineral, a sulphide of iron, has a shiny metallic lustre and was often mistaken for gold itself: it is the infamous fool's gold.(4) By anaerobic bacterial action, sulphates are reduced to sulphides and organic material is broken down, ultimately to yield carbon dioxide and methane.(5) Flasks and bottles full of nitrates and sulphides and chlorates and acetone, labelled in English and Arabic, lay on dirty tables.(6) These pollutants include ozone, sulphides , nitrogen oxides, carbon monoxide, hydrocarbons, and sulphur oxides.(7) One is a copper sulfate assemblage, which is generally associated with copper carbonates, cuprite, sulfides , boltwoodite, and metazeunerite.(8) The solids used include natural clays and minerals, metal oxides and sulfides , metal salts, and mixed metal oxides.(9) The Podolia ash beds consist largely of clay minerals accompanied by a variety of primary volcanogenic crystals and secondary sulphides , sulphates, oxides, carbonates, and silicates.(10) In this paper, we show that the opaline silica and amorphous sulphides are precipitating mainly on filamentous microbes and biofilms, which form templates for both the metal-rich sinter and the suspended flocs.(11) Most pure metals, when freshly cut to expose a new surface, are lustrous, but most lose this luster quickly by combining with oxygen, carbon dioxide or hydrogen sulfide to form oxides, carbonates or sulfides .(12) These metals occurs in the earth in the form of sulfides , such as copper sulfide, lead sulfide, and zinc sulfide (ZnS).(13) Also, the inevitable non-metallic inclusions, i.e. oxides, silicates, sulphides , are broken up, some deformed, and distributed throughout the steel in a more uniform manner.(14) The technique can identify iron-bearing phases (such as oxides, silicates, sulfides , sulfates, and carbonates), as well as the amount of iron in each phase and the presence of iron in various oxidation states.(15) However, only a small fraction (roughly 3 per cent on average) of the crustal abundance of most minerals exists in non-silicate form, as oxides, sulphides , or carbonates.(16) In situations where large amounts of sulfides are being oxidized in this way, an enormous amount of acidity is associated with the sulfate product.
