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Lead Compounds
Compounds of lead exist with lead in two main oxidation states: +2 and +4. The former is more common. Inorganic lead(IV) Compound (chemistry), compounds are typically strong oxidants or exist only in highly acidic solutions. Chemistry Various oxidized forms of lead are easily reduced to the metal. An example is heating PbO with mild organic reducing agents such as glucose. The mixture of the oxide and the sulfide heated together will also form the metal. : 2 PbO + PbS → 3 Pb + SO2 Metallic lead is attacked (oxidized) only superficially by air, forming a thin layer of lead oxide that protects it from further oxidation. The metal is not attacked by sulfuric acid, sulfuric or hydrochloric acid, hydrochloric acids. It dissolves in nitric acid with the evolution of nitric oxide gas to form dissolved lead(II) nitrate, Pb(NO3)2. : 3 Pb + 8 H+ + 8 → 3 Pb2+ + 6 + 2 NO + 4 H2O When heated with nitrates of alkali metals, metallic lead oxidizes to form lead(II) oxide, PbO (also k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A Piece Of Lead
A, or a, is the first letter and the first vowel letter of the Latin alphabet, used in the modern English alphabet, and others worldwide. Its name in English is '' a'' (pronounced ), plural ''aes''. It is similar in shape to the Ancient Greek letter alpha, from which it derives. The uppercase version consists of the two slanting sides of a triangle, crossed in the middle by a horizontal bar. The lowercase version is often written in one of two forms: the double-storey and single-storey . The latter is commonly used in handwriting and fonts based on it, especially fonts intended to be read by children, and is also found in italic type. In English, '' a'' is the indefinite article, with the alternative form ''an''. Name In English, the name of the letter is the ''long A'' sound, pronounced . Its name in most other languages matches the letter's pronunciation in open syllables. History The earliest known ancestor of A is ''aleph''—the first letter of the Phoenician ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Sulfate
Lead(II) sulfate (PbSO4) is a white solid, which appears white in microcrystalline form. It is also known as ''fast white'', ''milk white'', ''sulfuric acid lead salt'' or ''anglesite''. It is often seen in the plates/electrodes of car batteries, as it is formed when the battery is discharged (when the battery is recharged, then the lead sulfate is transformed back to metallic lead and sulfuric acid on the negative terminal or lead dioxide and sulfuric acid on the positive terminal). Lead sulfate is poorly soluble in water. Structure Anglesite (lead(II) sulfate, ) adopts the same orthorhombic crystal structure as celestite ( strontium sulfate, ) and barite (barium sulfate, ). All three minerals' structures are in the space group ''Pbnm'' (number 62). Each lead(II) ion is surrounded by 12 oxygen atoms from 7 sulfate ions, forming a PbO12 polyhedron. The lead–oxygen distances range from 2.612 Å to 3.267 Å and the average distance is 2.865 Å. Manufacturing Lead(II) sulfate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Tetroxide
Lead(II,IV) oxide, also called red lead or minium, is the inorganic compound with the formula . A bright red or orange solid, it is used as pigment, in the manufacture of batteries, and rustproof primer paints. It is an example of a mixed valence compound, being composed of both Pb(II) and Pb(IV) in the ratio of two to one. Structure Lead(II,IV) oxide is lead(II) orthoplumbate(IV) . It has a tetragonal crystal structure at room temperature, which then transforms to an orthorhombic ( Pearson symbol ''oP''28, Space group Pbam, No. 55) form at temperature . This phase transition only changes the symmetry of the crystal and slightly modifies the interatomic distances and angles. File:Red-lead-unit-cell-3D-balls.png, Unit cell of tetragonal (Key: Pb O) File:Red-lead-3D-balls.png, Part of tetragonal red lead's crystal structure Preparation Lead(II,IV) oxide is prepared by calcination of lead(II) oxide (PbO; also called litharge) in air at about 450–480 °C: : ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plumbate
In chemistry, a plumbate often refers to compounds that can be viewed as derivatives of the hypothetical anion. Examples Halides Salts of , , , etc. are labeled as iodoplumbates. Lead perovskite semiconductors are often described as plumbates. Lead oxyanions Plumbates are formed by the reaction of lead(IV) oxide, , with alkali. Plumbate salts contain either the hydrated ''hexahydroxoplumbate(IV)'' or ''plumbate'' anion , or the anhydrous anions (''metaplumbate'') or (''orthoplumbate''). For example, dissolving in a hot, concentrated aqueous solution of potassium hydroxide forms the potassium hexahydroxoplumbate(IV) salt . The anhydrous salts may be synthesized by heating metal oxides or hydroxides with . The most widely discussed plumbates are derivatives of barium metaplumbate . When doped with some bismuth in place of lead, the material exhibits superconductivity at 13 K. At the time of this discovery, oxides did not show such properties. The surprise associated with this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Tetrachloride
Lead tetrachloride, also known as lead(IV) chloride, has the molecular formula PbCl4. It is a yellow, oily liquid which is stable below 0 °C, and decomposes at 50 °C. It has a tetrahedral configuration, with lead as the central atom. The Pb– Cl covalent bonds have been measured to be 247 pm and the bond energy is 243 kJ⋅mol−1. Synthesis Lead tetrachloride can be made by reacting lead(II) chloride PbCl2, and hydrochloric acid HCl, in the presence of chlorine gas (Cl2), leading to the formation of chloroplumbic acid H2PbCl6. It is then converted to the ammonium salt (NH4)2PbCl6 by adding ammonium chloride (NH4Cl). Finally, the solution is treated with concentrated sulfuric acid H2SO4, to separate out lead tetrachloride. This series of reactions is conducted at 0 °C. The following equations illustrate the reaction: :PbCl2 + 2HCl + Cl2 → H2PbCl6 :H2PbCl6 + 2 NH4Cl → (NH4)2PbCl6 + 2HCl :(NH4)2PbCl6 + H2SO4 → PbCl4+ 2HCl + (N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidizing Agent
An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ''electron donor''). In other words, an oxidizer is any substance that oxidizes another substance. The oxidation state, which describes the degree of loss of electrons, of the oxidizer decreases while that of the reductant increases; this is expressed by saying that oxidizers "undergo reduction" and "are reduced" while reducers "undergo oxidation" and "are oxidized". Common oxidizing agents are oxygen, hydrogen peroxide, and the halogens. In one sense, an oxidizing agent is a chemical species that undergoes a chemical reaction in which it gains one or more electrons. In that sense, it is one component in an oxidation–reduction (redox) reaction. In the second sense, an oxidizing agent is a chemical species that transfers electronegative atoms, usually oxygen, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Dioxide
Lead(IV) oxide, commonly known as lead dioxide, is an inorganic compound with the chemical formula . It is an oxide where lead is in an oxidation state of +4. It is a dark-brown solid which is insoluble in water. It exists in two crystalline forms. It has several important applications in electrochemistry, in particular as the positive plate of lead acid batteries. Properties Physical Lead dioxide has two major polymorphs, alpha and beta, which occur naturally as rare minerals scrutinyite and plattnerite, respectively. Whereas the beta form had been identified in 1845, α- was first identified in 1946 and found as a naturally occurring mineral 1988. The alpha form has orthorhombic symmetry, space group Pbcn (No. 60), Pearson symbol ''oP''12, lattice constants ''a'' = 0.497 nm, ''b'' = 0.596 nm, ''c'' = 0.544 nm, ''Z'' = 4 (four formula units per unit cell). The lead atoms are six-coordinate. The symmetry of the beta form is tetragonal, space group P42/mnm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halogenation
In chemistry, halogenation is a chemical reaction which introduces one or more halogens into a chemical compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers, drugs. This kind of conversion is in fact so common that a comprehensive overview is challenging. This article mainly deals with halogenation using elemental halogens (). Halides are also commonly introduced using salts of the halides and halogen acids. Many specialized reagents exist for introducing halogens into diverse substrates, e.g. thionyl chloride. Organic chemistry Several pathways exist for the halogenation of organic compounds, including free radical halogenation, ketone halogenation, electrophilic halogenation, and halogen addition reaction. The nature of the substrate determines the pathway. The facility of halogenation is influenced by the halogen. Fluorine and chlorine are more electrophilic and are more aggressive haloge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plumbite
In chemistry, plumbite is the oxyanion or hydrated forms, or any salt containing this anion. In these salts, lead is in the oxidation state +2. It is the traditional term for the IUPAC name plumbate(II). For example, lead(II) oxide (PbO) dissolves in alkali to form salts containing the anion (hydrogen plumbite): : Lead(II) hydroxide also dissolves in excess alkali to form the anion (hexahydroxyplumbate(II)): : The plumbite ion is a weak reducing agent. When it functions as one, it is oxidized to the plumbate ion. See also * Plumbate *Lead *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 ... References Lead(II) compounds Oxyanions {{Inorganic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxide
Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a single covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, a ligand, a nucleophile, and a catalyst. The hydroxide ion forms salts, some of which dissociate in aqueous solution, liberating solvated hydroxide ions. Sodium hydroxide is a multi-million-ton per annum commodity chemical. The corresponding electrically neutral compound HO• is the hydroxyl radical. The corresponding covalently bound group of atoms is the hydroxy group. Both the hydroxide ion and hydroxy group are nucleophiles and can act as catalysts in organic chemistry. Many inorganic substances which bear the word ''hydroxide'' in their names are not ionic compounds of the hydroxide ion, but covalent compounds which contain hydroxy groups. Hydroxide ion The hydroxide ion is naturally produced ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkali Metal
The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K),The symbols Na and K for sodium and potassium are derived from their Latin names, ''natrium'' and ''kalium''; these are still the origins of the names for the elements in some languages, such as German and Russian. rubidium (Rb), caesium (Cs), and francium (Fr). Together with hydrogen they constitute Group (periodic table)#Group names, group 1, which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in their having very similar characteristic properties. Indeed, the alkali metals provide the best example of periodic trends, group trends in properties in the periodic table, with elements exhibiting well-characterised Homologous series, homologous behaviour. This family of elements is also known as the lithium family after its leading element. The alkali metals are all shiny, hardness, sof ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Acetate
Lead () is a chemical element; it has symbol Pb (from Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases, and it tends to form covalent bonds. Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited to organolead compounds. Like the lighter members of the group, lead tends to bond with itself; it can form chains and pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
