Malleable, metals

Properties. Uranium metal is a dense, bright silvery, ductile, and malleable metal. Uranium is highly electropositive, resembling magnesium, and tarnishes rapidly on exposure to air. Even a poHshed surface becomes coated with a dark-colored oxide layer in a short time upon exposure to air. At elevated temperatures, uranium metal reacts with most common metals and refractories. Finely divided uranium reacts, even at room temperature, with all components of the atmosphere except the noble gases. The silvery luster of freshly cleaned uranium metal is rapidly converted first to a golden yellow, and then to a black oxide—nitride film within three to four days. Powdered uranium is usually pyrophoric, an important safety consideration in the machining of uranium parts. The corrosion characteristics of uranium have been discussed in detail (28). 

Of high purity, zirconium is a white, soft ductile and malleable metal. At 99% purity, when obtained at high temperatures it is hard and brittle. The rapid development of production techniques of zirconium has resulted because of its suitability for nuclear engineering equipment. 

A similar transformation to a metallic, tetragonal -form can be effected in Si and Ge by subjecting them to pressures of 200 and I20kbar respectively along the c-axis, and again the density increases by 25% from the value at atmospheric pressure. Lead is familiar as a blue-grey, malleable metal with a fairly high density (nearly 5 times that of Si and twice those of Ge and Sn, but only half that of Os and Ir). 

Fig. 7. The impingement of this jet can create a localized erosion (and even melting) responsible for surface pitting and ultrasonic cleaning (68-70). A second contribution to erosion created by cavitation involves the impact of shock waves generated by cavitational collapse. The magnitude of such shock waves can be as high as 104 atmospheres, which will easily produce plastic deformation of malleable metals (77). The relative magnitudes of these two effects depends heavily on the specific system under consideration.

However, ultrasonic rate enhancements of heterogeneous catalysis have usually been relatively modest (less than tenfold). The effect of irradiating operating catalysts is often simply due to improved mass transport (58). In addition, increased dispersion during the formation of catalysts under ultrasound (59) will enhance reactivity, as will the fracture of friable solids (e.g., noble metals on C or silica (60),(62),(62) or malleable metals (63)). 

Platinum (Pt, [Xe + 4/ l4]5r/96.s 1), name from the Spanishplatina (silver). Known and used by the pre-Columbian South-American Indians since ancient times. Re-discovered and noticed by the Western scientists in 1735 (Antonio de Ulloa). Silvery, white solid, ductile and malleable metal. 

Erbium is a soft, malleable metal with a silvery metallic luster that only tarnishes (oxidi2es) slightly in air. It is one of the rare-earths of the yttrium subgroup of the lanthanide series. 

Known to the ancients Soft, malleable metal excellent conductor of heat and electricity long used as currency made into jewelry and eating utensils used in photographic film. 

Swedish chemist Carl Gustaf Mosander Found in the minerals xenotime and euxerite of which it is an impurity soft and malleable metal has few uses other than in inexpensive glass and jewelry. 

Known to the ancients Soft, malleable metal used since Roman times in plumbing used to make batteries and in television and computer screens to reduce radiation many useful alloys and isotopes. 

Silvery-white malleable metal, cubic crystal melts at 660°C b. p. 2520°C density 2.70 g/cm insoluble in water, soluble in acids and alkalies. 

FORGING. Historical records do not note when Ihe lirsl humans discovered that certain malleable metals (such as gold, copper, and zinc) and (probably at a somewhat later time) some formulations of iron could he hammered and pounded into approximate shapes. Artifacts prove that the art of forging dates back to antiquity. 

Cadmium, Cd, at wt 112.4 soft blue-wh malleable metal or grayish- wh powd d 8.642 at 17°, mp 320.9°, bp 767° insol in w sol in acids and AN solns occurs chiefly as greenockite (CdS) associated with Zn(or Pb) manuf. Its toxicity is discussed by Sax(Ref 3). Fire and expln hazards are slight when Cd dust is exposed to heat or flame(Ref 3)... 

Lead exists in small quantities in the Earth s crust, but is well known as it is extracted easily from its ores. It is a grey, ductile, malleable metal which has been used extensively by man from earliest times, with references to it being found in Egyptian hieroglyphics of around 1500 BC. Amongst other uses, it was... 

Color Physical state Melting point Boiling point Densi ty Si 1ver-whi te Malleable metale 710°Cc 725°C 1600°Cc 1640°C 3.51 g/cm3 (at 20°C)... 

Properties Silver-white, lustrous, malleable metal. Sp. gr. 1.74. M. P. 650°. B. P. 1120°. In powdered or flake form it burns readily with a brilliant, bluish-white light and with evolution of great heat of combustion. Powder liberates hydrogen when iu contact with water. 

White, infusible and incandescent when hot. 2. Incrustation without metal White, yellow when hot. White, garlic odour. Brown. 3. Incrustation with metal White incrustation brittle metal. Yellow incrustation brittle metal. Yellow incrustation malleable metal, marks paper. 4. Metal without incrustation Grey metallic particles, attracted by magnet. Malleable beads. BaO, SrO, CaO, MgO (residue alkaline to litmus paper). A1203, ZnO, Si02 (residue not alkaline to litmus paper). ZnO. As203. CdO. Sb. Bi. Pb. Fe, Ni, Co. Ag and Sn (white), Cu (red flakes) Au. 

Dry test All gold compounds when heated upon charcoal with sodium carbonate yield yellow, malleable, metallic particles, which are insoluble in nitric acid, but soluble in aqua regia. The aqua regia solution should be evaporated to dryness, dissolved in water, and tests 1, 3 or 4 applied. 

Highly ductile and malleable. Metals can withstand large deformations without fracturing. They can be drawn into wires, hammered into horseshoes, or bent into paper clips. 

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