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Lead(II) Acetate
Lead(II) acetate is a white crystalline chemical compound with a slightly sweet taste. Its chemical formula is usually expressed as or , where Ac represents the acetyl group. Like many other lead compounds, it causes lead poisoning. Lead acetate is soluble in water and glycerin. With water it forms the trihydrate, , a colourless or white efflorescent monoclinic crystalline substance. The substance is used as a reagent to make other lead compounds and as a fixative for some dyes. In low concentrations, it formerly served as the principal active ingredient in progressive types of hair colouring dyes. Lead(II) acetate is also used as a mordant in textile printing and dyeing, and as a drier in paints and varnishes. It was historically used as a sweetener and preservative in wines and in other foods and for cosmetics. Production Lead(II) acetate can be made by boiling elemental lead in acetic acid and hydrogen peroxide. This method will also work with lead(II) carbonat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saturn (mythology)
Saturn ( ) was a god in Religion in ancient Rome, ancient Roman religion, and a character in Roman mythology. He was described as a god of time, generation, dissolution, abundance, wealth, agriculture, periodic renewal and liberation. Saturn's mythological reign was depicted as a Golden Age of abundance and peace. After the Roman conquest of Greece, he was conflated with the Greek Titan Cronus. Saturn's consort was his sister Ops, with whom he fathered Jupiter (mythology), Jupiter, Neptune (mythology), Neptune, Pluto (mythology), Pluto, Juno (mythology), Juno, Ceres (Roman mythology), Ceres and Vesta (mythology), Vesta. Saturn was especially celebrated during the festival of Saturnalia each December, perhaps the most famous of the Roman festivals, a time of feasting, role reversals, free speech, gift-giving and revelry. The Temple of Saturn in the Forum Romanum, Roman Forum housed the state treasury and archives (''aerarium'') of the Roman Republic and the early Roman Empire. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hair Colouring
Hair coloring, or hair dyeing, is the practice of changing the hair color, color of the hair on humans' heads. The main reasons for this are cosmetic: to cover Gray hair, gray or white hair, to alter hair to create a specific look, to change a color to suit preference or to restore the original hair color after it has been discolored by hairdressing processes or Hair bleaching#Sun exposure, sun bleaching. Hair coloring can be done professionally by a hairdresser or independently at home. Hair coloring is very popular, with 50-80% of women in the United States, Europe, and Japan having reported using hair dye. At-home coloring in the United States reached sales of $1.9 billion in 2011 and was expected to rise to $2.2 billion by 2016. History The dyeing of hair is an ancient art that involves treatment of the hair with various chemical compounds. Assyrian herbals dating back to contain some of the oldest recipes for cosmetic preparations known, including hair dye. The ancient ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper Acetate
Copper(II) acetate, also referred to as cupric acetate, is the chemical compound with the formula where is acetate (). The hydrated derivative, , which contains one molecule of water for each copper atom, is available commercially. Anhydrous copper(II) acetate is a dark green crystalline solid, whereas is more bluish-green. Since ancient times, copper acetates of some form have been used as fungicides and green pigments. Today, copper acetates are used as reagents for the synthesis of various inorganic and organic compounds. Copper acetate, like all copper compounds, emits a blue-green glow in a flame. Structure Copper acetate hydrate adopts the paddle wheel structure seen also for related Rh(II) and Cr(II) tetraacetates. One oxygen atom on each acetate is bound to one copper atom at . Completing the coordination sphere are two water ligands, with distances of . The two copper atoms are separated by only , which is close to the separation in metallic copper. The two copper c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-displacement Reaction
A single-displacement reaction, also known as single replacement reaction or exchange reaction, is an archaic concept in chemistry. It describes the stoichiometry of some chemical reactions in which one element or ligand is replaced by an atom or group. It can be represented generically as: :A + BC -> AC + B where either *A and B are different metals (or any element that forms cation like hydrogen) and C is an anion; or *A and B are halogens and C is a cation. This will most often occur if A is more reactive than B, thus giving a more stable product. The reaction in that case is exergonic and spontaneous. In the first case, when A and B are metals, BC and AC are usually aqueous compounds (or very rarely in a molten state) and C is a spectator ion (i.e. remains unchanged). : A(s) + \underbrace_ -> \underbrace_ + B(s) In the reactivity series, the metals with the highest propensity to donate their electrons to react are listed first, followed by less reactive ones. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead(II) Oxide
Lead(II) oxide, also called lead monoxide, is the inorganic compound with the molecular formula Pb O. It occurs in two polymorphs: litharge having a tetragonal crystal structure, and massicot having an orthorhombic crystal structure. Modern applications for PbO are mostly in lead-based industrial glass and industrial ceramics, including computer components. Types Lead oxide exists in two polymorphs: * Red tetragonal (α-PbO), obtained at temperatures below * Yellow orthorhombic (β-PbO), obtained at temperatures above Synthesis PbO may be prepared by heating lead metal in air at approximately . At this temperature it is also the end product of decomposition of other oxides of lead in air: :PbO2->[] Pb12O19 ->[] Pb12O17 ->[] Pb3O4 ->[] PbO Thermal decomposition of lead(II) nitrate or lead carbonate, lead(II) carbonate also results in the formation of PbO: :2 → 2 PbO + 4 + : → PbO + PbO is produced on a large scale as an intermediate product in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead(II) Carbonate
Lead(II) carbonate is the chemical compound with the chemical formula . It is a white, toxic solid. It occurs naturally as the mineral cerussite. Structure Like all metal carbonates, lead(II) carbonate adopts a dense, highly crosslinked structure consisting of intact and metal cation sites. As verified by X-ray crystallography, the Pb(II) centers are seven-coordinate, being surrounded by multiple carbonate ligands. The carbonate centers are bonded bidentate to a single Pb and bridge to five other Pb sites. Production and use Lead carbonate is manufactured by passing carbon dioxide into a cold dilute solution of lead(II) acetate, or by shaking a suspension of a lead salt more soluble than the carbonate with ammonium carbonate at a low temperature to avoid formation of basic lead carbonate. : Lead carbonate is used as a catalyst to polymerize formaldehyde to poly(oxymethylene). It improves the bonding of chloroprene to wire. Regulations The supply and use of this compound is r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmetics
Cosmetics are substances that are intended for application to the body for cleansing, beautifying, promoting attractiveness, or altering appearance. They are mixtures of chemical compounds derived from either Natural product, natural sources or created synthetically. Cosmetics have various purposes, including personal care, personal and skin care. They can also be used to conceal blemishes and enhance natural features (such as the eyebrows and eyelashes). Makeup can also add colour to a person's face, enhance a person's features or change the appearance of the face entirely to resemble a different person, creature, or object. People have used cosmetics for thousands of years for skin care and appearance enhancement. Visible cosmetics for both women and men have gone in and out of fashion over the centuries. Some early forms of cosmetics contained harmful ingredients such as lead that caused serious health problems and sometimes resulted in death. Modern commercial cosmetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preservative
A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or by undesirable chemical changes. In general, preservation is implemented in two modes, chemical and physical. Chemical preservation entails adding chemical compounds to the product. Physical preservation entails processes such as refrigeration or drying.Erich Lück and Gert-Wolfhard von Rymon Lipinski "Foods, 3. Food Additives" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2002, Wiley-VCH, Weinheim. Preservative food additives reduce the risk of foodborne infections, decrease microbial spoilage, and preserve fresh attributes and nutritional quality. Some physical techniques for food preservation include dehydration, UV-C radiation, freeze-drying, and refrigeration. Chemical preservation and physical preservation techniques ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sweetener
A sweetener is a substance added to food or drink to impart the flavor of sweetness, either because it contains a type of sugar, or because it contains a sweet-tasting sugar substitute. Various natural non-sugar sweeteners (NSS) and artificial sweeteners are used to produce food and drink. List of sweeteners Many artificial sweeteners have been invented and are now used in commercially produced food and drink. Natural non-sugar sweeteners also exist, such as glycyrrhizin found in liquorice. * Sugar ** Sugar alcohol ** Sucrose, or glucose-fructose, commonly called ''table sugar'' *** Fructose, or ''fruit sugar'' *** Glucose, or dextrose * Sugar substitute, including ''artificial sweetener'' * Syrups ** Agave syrup, or ''agave nectar'' ** Maple syrup ** Corn syrup *** High-fructose corn syrup (HFCS), used industrially * Honey * Molasses * Dates * Glycyrrhizin, found in liquorice Liquorice ( Commonwealth English) or licorice (American English; see spelling differences ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varnish
Varnish is a clear Transparency (optics), transparent hard protective coating or film. It is not to be confused with wood stain. It usually has a yellowish shade due to the manufacturing process and materials used, but it may also be pigmented as desired. It is sold commercially in various shades. Varnish is primarily used as a wood finishing, wood finish where, stained or not, the distinctive tones and grains in the wood are intended to be visible. Varnish finishes are naturally Gloss (material appearance), glossy, but satin/semi-gloss and flat sheens are available. History The word "varnish" comes from Mediaeval Latin ''vernix'', meaning odorous resin, perhaps derived from Middle Greek ''berōnikón'' or ''beroníkē'', meaning amber or amber-colored glass. A false etymology traces the word to the Greek ''Berenice'', the ancient name of modern Benghazi in Libya, where the first varnishes in the Mediterranean area were supposedly used and where resins from the trees of now-v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paint
Paint is a material or mixture that, when applied to a solid material and allowed to dry, adds a film-like layer. As art, this is used to create an image or images known as a painting. Paint can be made in many colors and types. Most paints are either oil-based or water-based, and each has distinct characteristics. Primitive forms of paint were used tens of thousands of years ago in cave paintings. Clean-up solvents are also different for water-based paint than oil-based paint. Water-based paints and oil-based paints will cure differently based on the outside ambient temperature of the object being painted (such as a house). History Paint was used in some of the earliest known human artworks. Some cave paintings drawn with red or yellow ochre, hematite, manganese oxide, and charcoal may have been made by early ''Homo sapiens'' as long as 40,000 years ago. Paint may be even older. In 2003 and 2004, South African archeologists reported finds in Blombos Cave of a 100,000-y ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oil Drying Agent
An oil drying agent, also known as siccative, is a coordination compound that accelerates ( catalyzes) the hardening of drying oils, often as they are used in oil-based paints. This so-called "drying" (actually a chemical reaction that produces an organic plastic) occurs through free-radical chemical crosslinking of the oils. The catalysts promote this free-radical autoxidation of the oils with air. Typical oil drying agents are derived from ions of cobalt, manganese, and iron, prepared as "salts" of lipophilic carboxylic acids such as naphthenic acids, in order to give them a soap-like chemical formula and make them oil-soluble. Varieties of drying agents In technical literature, oil drying agents, such as naphthenates, are described as salts, but they are probably also non-ionic coordination complexes with structures similar to basic zinc acetate. These catalysts were traditionally hydrocarbon carboxylate chelates of lead, but due to lead's toxicity, cobalt and other e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
