Barium carbonate, BaCO

While a binary oxide can be used as a starting material, some of these are reactive compounds that are difficult to handle. For example, BaO reacts rapidly with C02 in the air to produce barium carbonate. Other oxides, including BaO, are hygroscopic. Thus, compounds which are unreactive towards C02 and HzO at room temperature, but decompose to oxides plus volatile gases at elevated temperatures, are often used as oxide precursors. In the case of barium, BaCOs is a stable compound under ambient conditions but decomposes upon heating to 950°C according to the reaction... 

To the laboratory student, e.g., barium carbonate is BaCOs, sulphuric acid is H2S04, hydrochloric acid is HC1, and their equivalents are respectively 197, 98, and 2 x 36 5 = 73. In... 

Barium carbonate n. BaCOs. A white compound, insoluble in water, occurring as a mineral or made by direct precipitation. It has a Sp gr of 4.275 and a mp of 1360°C. It is used in ceramics, fillers, and extenders. Syn witherite (See image). Ash M, Ash I (1998) Handbook of fillers, extenders and dilutents. Synapse Information Resources Inc., New York. 

The filler, ferroelectric ceramic material (Barium Sodium Niobate (BNN)) was prepared by usual ceramic technique using reagent grade sodium carbonate, barium carbonate, and niobium pentoxide. Solid-state reaction technique was adopted for the preparation of BNN. The starting materials were BaCO (Merck Ltd., Mumbai, India), Na2C03 and Nb O (CDH, New Delhi, India). The powders were taken by satisfying the stoichiometric ratios (eqrration 16.1), mixed, milled and calcined at a temperature of 1000 °C for 3 h. Sintering was carried out at a temperatrrre of 1200 °C for 5 hrs. 

The first report concerning barium compounds occurred in the early part of the seventeenth century when it was noted that the ignition of heavy spar gave a peculiar green light. A century later, Scheele reported that a precipitate formed when sulfuric acid was added to a solution of barium salts. The presence of natural barium carbonate, witherite [14941-39-0] BaCO, was noted in Scodand by Withering. 

Most barium compounds are prepared from reactions of barium carbonate [513-77-9] BaCO, which is commercially manufactured by the "black ash" process from barite and coke ki a process identical to that for strontium carbonate production. Depending on the co-product, soda ash and/or carbon dioxide are also consumed. 

A pliotornicrograpli of barium carbonate fomied by precipitation using pure soda asli (eq. 9), is shown in Figure 3. Tire av erage particle size is 1.2 ]lm. Tire exclusive use of soda ash results in a barium carbonate having included sodium that cannot be reduced below a certain level by repeated washings. Tire sodium can be detrimental if the BaCO is to be used for barium titanate production. 

Barium is the 17th most abundant element in the Earth s crust, making up about 0.05% of the crust. It is found in the minerals witherite, which is barium carbonate (BaCO ), and barite, known as barium siflfate (BaSO ). Pure barium metal does not exist on Earth—only as compounds or in minerals and ores. Barium ores are found in Missouri, Arkansas, Georgia, Kentucky, Nevada, California, Canada, and Mexico. 

Barium Minerals Barite (BaS04) and witherite (BaCOs) are commonly used to supply barium in ceramic formulations. Purified barium carbonate, made by dissolution and repredpitation, is used most frequently in ceramic processes and as fluxing compounds in the grazes, ass, and enamels of electronic ceramics and in heavy day products to prevent scumming. The use of these minerals have the drawback that upon heating they give off gas, which can cause cracks. 

Violent reaction with benzoyl chloride combined with KOH, Bt2, barium carbonate, CS2, Cr(OCl)2, Cu, Pb, HNO3, BaCOs, H2SO4, hot water, (CH3)2S04, dibromomalononitrile, sulfuric acid. Incompatible with acids, ammonium chloride + trichloroacetonitrile, phosgene, cyanuric chloride, 2,5-dinitro-3-methylbenzoic acid + oleum, trifiuroroacryloyl chloride. Reacts with heavy metals (e.g., brass, copper, lead) to form dangerously explosive heavy metal azides, a particular problem in laboratory equipment and drain traps. When heated to decomposition it emits very toxic fumes of NOx and Na20. See also AZIDES. 

Some substitution of strontium (up to 14 mol.%), of lead (2 mol.% reported) but no barium has been reported in aragonite, although investigations at elevated temperatures and pressures show almost complete miscibility of these elements in the structure (Gaines et al., 1997, p. 442), and SrCOs (strontionite), BaCOs (witherite), and PbCOs (cerussite) are common minerals. A calculated plot (Figure 3(b)) for cations in ninefold coordination shows that this coordination theoretically allows trivalent rare earth elements and quadravalent and many other elements to be substituents in the structure. Ytterbium, europium, samarium, and radium carbonates with aragonite structure have been synthesized (Spear, 1983). 

BaCO.]—Barium has an oxidation number of +2 and carbonate has an oxidation number of -2, so they combine in a 1 1 ratio. No parentheses are used because we only need one carbonate. 

We will assume that we have a source of cheap barium carbonate guaranteed to contain 95 per cent, of BaCOs delivered to us finely ground at 2, 10s. per ton. We will further assume that we can buy sufficient quantities of muriatic acid at 1, 10s. per ton delivered at the works, and that we are up to the present buying barium chloride at the rate of 6, 10s. per ton delivered at our works, of which we use 10 tons per week in another branch of our works. What will it cost to produce that quantity, and will it be cheaper to continue buying barium chloride or to make the article ourselves ... 

BaCOs. We therefore have the following data. For every ton of barium carbonate used we have available for conversion into barium chloride -95 —"0122 ton = -9378 ton BaCOs, which will require 1-392 tons of our hydrochloric acid, and should... 

A Many starting materials could be used, but barium oxide (BaO) is not a suitable choice. BaO is highly hygroscopic and absorbs carbon dioxide from the air. This means an amount of BaO/Ba(OH) / BaCO would be weighed out rather than the molar quantity of BaO required. The mixture of starting materials would be deficient in barium, and hence, so would the product. In cases like these, where the logical choice is unsuitable, a metal carbonate or nitrate would be used. These metal salts decompose stoichiometrically to the oxide on heating ... 

Strobel et al. [51] prepared barium carbonate nanoparticles (50-100 nm) by flame spray pyrolysis. The rapid quenching during the preparation process resulted in the unprecedented formation of pure monoclinic BaCOa- The as-prepared material was characterized by electron microscopy, XRD as well as by TG and DSC analyses (Figures 6 and 7). At ambient conditions the metastable monoclinic phase transformed easily into the thermodynamically stable orthorhombic BaCOs (witherite) within a few days. 

Finally, commercial BaCh has the advantage of higher purity. The major impurity in barium chemicals is strontium, which is itself an impurity requiring control, and it is important not to create a new problem while solving an existing one. BaCl2 usually has the lower strontium content. BaCOs, on the other hand, usually has the important advantage of a lower cost, and it is also a source of carbonate ion. It can precipitate both calcium and sulfate. 

When heated, both barium carbonate (BaC03) and calcium carbonate (CaC03) release carbon dioxide (CO2), leaving barium oxide (BaO) and calcium oxide (CaO), respectively. In an experiment, a mixture of BaCOs and CaCOs with a combined mass of 63.67 g produces 19.67 g of CO2. Calculate the mole and mass fractions of barium carbonate and calcium carbonate in the original mixture, assuming complete decomposition of the compounds. 

Barium carbonate, BaCO 2.0X10 Copper(II) hydroxide, Cu(OH)2 2.2X 10 ... 

The barium content in the lithosphere is ca. 500 mg/kg (i.e., ppm wt.), but, owing to its chemical reactivity, the metal does not occur free in nature. The chief barium-containing minerals are the sulfate barite or heavy spar [BaSO orthorhombic] and the carbonate with-erite [BaCO, orthorhombic). 

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