Barium elements

The evidence for this supposed process came from chemical analysis. Hahn and Strassmann published a scientific paper showing that small amounts of barium (element 56) were produced when uranium (element 92) was bombarded with neutrons. It was very puzzling to them how a single neutron could transform element 92 into element 56. 

Strontium, element number 38, has a density of 2.63 g/cm3 and is the 16th most abundant element on Earth. Barium, element number 56, has a density of 3.51 g/cm3 and ranks 14th in abundance. Both elements are silvery-colored metals. Because alkaline earths react so readily with any water in the environment to form ions and compounds, neither element would ever be found as the native metal. In all of their ores, they occur as +2 ions. The principal sources of the two elements are the minerals celestite (SrS04), strontianite (SrC03), and barite (BaS04). 

It seemed their radium isotopes must be barium, element 56, slightly more than half as heavy as uranium and with just over half its charge. Hahn and Strassmann could hardly believe it. They conceived an even... 

Group IIB and know that this means the group of elements zine. cadmium and mercury, whilst Group IIA refers to the alkaline earth metals beryllium, magnesium, calcium, barium and strontium. 

The elements in Group II of the Periodic Table (alkaline earth metals) are. in alphabetical order, barium (Ba). beryllium (Be), calcium (Ca). magnesium (Mg), radium (Ra) and strontium (Sr). 

This is a radioactive element. It occurs in minute traces in barium and thorium minerals, but it can be produced by irradiation of bismuth in a nuclear reactor. (The study of its chemistry presents great difficulty because of its intense a radiation). 

Barium is a metallic element, soft, and when pure is silvery white like lead it belongs to the alkaline earth group, resembling calcium chemically. The metal oxidizes very easily and should be kept under petroleum or other suitable oxygen-free liquids to exclude air. It is decomposed by water or alcohol. 

Laser isotope separation techniques have been demonstrated for many elements, including hydrogen, boron, carbon, nitrogen, oxygen, sHicon, sulfur, chlorine, titanium, selenium, bromine, molybdenum, barium, osmium, mercury, and some of the rare-earth elements. The most significant separation involves uranium, separating uranium-235 [15117-96-1], from uranium-238 [7440-61-1], (see Uranium and uranium compounds). The... 

In general, the chemistry of inorganic lead compounds is similar to that of the alkaline-earth elements. Thus the carbonate, nitrate, and sulfate of lead are isomorphous with the corresponding compounds of calcium, barium, and strontium. In addition, many inorganic lead compounds possess two or more crystalline forms having different properties. For example, the oxides and the sulfide of bivalent lead are frequendy colored as a result of their state of crystallisation. Pure, tetragonal a-PbO is red pure, orthorhombic P PbO is yeUow and crystals of lead sulfide, PbS, have a black, metallic luster. 

The names adopted for salts consisted of a generic part derived from the acid and a specific part from the metallic base r oxide de plomb + I acide sulfurique le sulfate de plomb. The names for salts of acids containing an element in different degrees of oxidation were given different terminations sufte de soude and sulfate de soude for sodium sulfite and sulfate, and nitrite de baryte and nitrate de baryte for barium nitrite and nitrate. 

Some nut trees accumulate mineral elements. Hickory nut is notable as an accumulator of aluminum compounds (30) the ash of its leaves contains up to 37.5% of AI2O2, compared with only 0.032% of aluminum oxide in the ash of the Fnglish walnut s autumn leaves. As an accumulator of rare-earth elements, hickory greatly exceeds all other plants their leaves show up to 2296 ppm of rare earths (scandium, yttrium, lanthanum, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium). The amounts of rare-earth elements found in parts of the hickory nut are kernels, at 5 ppm shells, at 7 ppm and shucks, at 17 ppm. The kernel of the Bra2d nut contains large amounts of barium in an insoluble form when the nut is eaten, barium dissolves in the hydrochloric acid of the stomach. 

However, the peroxomonophosphate ion decomposes relatively rapidly ia aqueous solution. A mixture of peroxodiphosphoric and peroxomonophoshoric acids can be produced by treatiag a cold phosphoric acid solution with elemental fluorine (qv) (49). Peroxodiphosphoric acid is not produced commercially. Ammonium, lithium, sodium, potassium, mbidium, cesium, barium, 2iac, lead, and silver salts have all been reported. The crystal stmctures of the ammonium, lithium, sodium, and potassium compounds, which crysta11i2e with varyiag numbers of water molecules, have been determined (50). 

Strontium [7440-24-6] Sr, is in Group 2 (IIA) of the Periodic Table, between calcium and barium. These three elements are called alkaline-earth metals because the chemical properties of the oxides fall between the hydroxides of alkaU metals, ie, sodium and potassium, and the oxides of earth metals, ie, magnesium, aluminum, and iron. Strontium was identified in the 1790s (1). The metal was first produced in 1808 in the form of a mercury amalgam. A few grams of the metal was produced in 1860—1861 by electrolysis of strontium chloride [10476-85-4]. 

Sulfamic acid and its salts retard the precipitation of barium sulfate and prevent precipitation of silver and mercury salts by alkah. It has been suggested that salts of the type AgNHSO K [15293-60 ] form with elemental metals or salts of mercury, gold, and silver (19). Upon heating such solutions, the metal deposits slowly ia mirror form on the wall of a glass container. Studies of chemical and electrochemical behavior of various metals ia sulfamic acid solutions are described ia Reference 20. 

Other preparative methods include direct synthesis from the elements, reaction between gaseous hydrogen fluoride and titanium tetrachloride, and decomposition of barium hexafluorotitanate [31252-69-6] BaTiF, or ammonium, (NH 2TiFg. 

Barium metal is produced commercially by the reduction of barium oxide with a less reactive, nonvolatile element, usually aluminum (16—22). Depending on initial stoichiometry, two overall reactions occur in the BaO reduction ... 

Barium is a member of the aLkaline-earth group of elements in Group 2 (IIA) of the period table. Calcium [7440-70-2], Ca, strontium [7440-24-6], Sr, and barium form a closely aUied series in which the chemical and physical properties of the elements and thek compounds vary systematically with increa sing size, the ionic and electropositive nature being greatest for barium (see Calcium AND CALCIUM ALLOYS Calcium compounds Strontium and STRONTIUM compounds). As size increases, hydration tendencies of the crystalline salts increase solubiUties of sulfates, nitrates, chlorides, etc, decrease (except duorides) solubiUties of haUdes in ethanol decrease thermal stabiUties of carbonates, nitrates, and peroxides increase and the rates of reaction of the metals with hydrogen increase. 

Barium hydroxide is the strongest base and has the greatest water-solubility of the alkaline-earth elements. Barium hydroxide (barium hydrate, caustic baryta) exists as the octahydrate [12230-71 -6], Ba(OH)2 8H20, the monohydrate [22326-55-2], Ba(OH)2 H20, or as the anhydrous [17194-00-2] material, Ba(OH)2. The octahydrate and monohydrate have sp gr 2.18 and 3.74, respectively. The mp of the octahydrate and anhydrous are 77.9 °C and 407°C, respectively. 

Barium sulfide solutions undergo slow oxidation in air, forming elemental sulfur and a family of oxidized sulfur species including the sulfite, thiosulfate, polythionates, and sulfate. The elemental sulfur is retained in the dissolved bquor in the form of polysulfide ions, which are responsible for the yellow color of most BaS solutions. Some of the mote highly oxidized sulfur species also enter the solution. Sulfur compound formation should be minimized to prevent the compounds made from BaS, such as barium carbonate, from becoming contaminated with sulfur. 

The classical analytical method of deterruination of barium ion is gravimetric, by precipitating and weighing insoluble barium sulfate. Barium chromate, which is more insoluble than strontium chromate in a slightly acidic solution, gives a fairly good separation of the two elements. 

BeryUium reacts with fused alkaU haUdes releasing the alkaU metal until an equUibrium is estabUshed. It does not react with fused haUdes of the alkaline-earth metals to release the alkaline-earth metal. Water-insoluble fluoroberyUates, however, are formed in a fused-salt system whenever barium or calcium fluoride is present. BeryUium reduces haUdes of aluminum and heavier elements. Alkaline-earth metals can be used effectively to reduce beryUium from its haUdes, but the use of alkaline-earths other than magnesium [7439-95-4] is economically unattractive because of the formation of water-insoluble fluoroberyUates. Formation of these fluorides precludes efficient recovery of the unreduced beryUium from the reaction products in subsequent processing operations. 

Calcium [7440-70-2J, Ca, a member of Group 2 (IIA) of the Periodic Table between magnesium and strontium, is classified, together with barium and strontium, as an alkaline-earth metal and is the lightest of the three. Calcium metal does not occur free in nature however, in the form of numerous compounds, it is the fifth most abundant element constituting 3.63% of the earth s cmst. 

Cesium was first produced ia the metallic state by electrolysis of a molten mixture of cesium and barium cyanides (2). Subsequentiy the more common thermochemical—reduction techniques were developed (3,4). There were essentially no iadustrial uses for cesium until 1926, when it was used for a few years as a getter and as an effective agent ia reduciag the electron work function on coated tungsten filaments ia radio tubes. Development of photoelectric cells a few years later resulted ia a small but steady consumption of cesium and other appHcations for cesium ia photosensing elements followed. 

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