Bismuth melting point

When heated in air, bismuth burns with a blue flame, giving off clouds of its yellow oxide. Bismuths melting point is 271.40°C, its boiling point is 1,564°C, and its density is 9.807 g/cm. ... 

In hquidation, tin is heated on the sloping hearth of a small reverberatory furnace to just above its melting point. The tin mns into a so-called poling ketde, and metals that melt sufficiently higher than tin remain in the dross. Most of the iron is removed in this manner. Lead and bismuth remain, but arsenic, antimony, and copper are partly removed as dross. 

Betterton-KroIIProcess. MetaHic calcium and magnesium are added to the lead bullion in a melt and form ternary compounds that melt higher than lead and are lower in density. By cooling the lead bath to a temperature close to the melting point of lead, the intermetalHc compounds high in bismuth content soHdify and float to the top where they are removed by skimming. 

Because bismuth expands on solidification and because it alloys with certain other metals to give low melting point alloys, bismuth is particularly weU suited for a number of uses. Alloys of bismuth can be made that expand, shrink, or remain dimensionally stable on solidification. AH other metals except gallium and antimony contract on solidification. Bismuth aHoys and uses are summarized in Table 5. 

Low resistance-high kA alloy (high melting point) copper-bismuth has a good resistance to cold... 

A mixture of 2.33 g of bismuth oxide (BijOa), 3.71 g of anhydrous sodium carbonate, and 7.64 g of triglycollamic acid and 40 cc of water was heated at B0°C on the water bath until all was dissolved. The solution was avaporated on the water bath to a syrup. The syrup was allowed to cool, during which time partial solidification occurred. It was then triturated with 300 cc of alcohol, and the solid anhydrous salt was collected on a filter, washed with alcohol, ground fine, and dried in a vacuum desiccator. This substance has a water solubility at 25°C of 31 S% by weight. It decomposes on heating in the melting point bath. 

Some alloys are softer than the component metals. The presence of big bismuth atoms helps to soften a metal and lower its melting point, much as melons would destabilize a stack of oranges because they just do not fit together well. A low-melting-point alloy of lead, tin, and bismuth is employed to control water sprinklers used in certain fire-extinguishing systems. The heat of the fire melts the alloy, which activates the sprinklers before the fire can spread. 

Calculate the relative number of atoms of each element contained in each of the following alloys (a) Wood s metal, which is a low-melting-point alloy used to trigger automatic sprinkler systems and is 12.5% tin, 12.5% cadmium, and 24% lead by mass in bismuth (b) a steel that is 1.75% by mass carbon in iron. 

Arsenic and antimony are metalloids. They have been known in the pure state since ancient times because they are easily obtained from their ores (Fig. 15.3). In the elemental state, they are used primarily in the semiconductor industry and in the lead alloys used as electrodes in storage batteries. Gallium arsenide is used in lasers, including the lasers used in CD players. Metallic bismuth, with its large, weakly bonded atoms, has a low melting point and is used in alloys that serve as fire detectors in sprinkler systems the alloy melts when a fire breaks out nearby, and the sprinkler system is activated. Like ice, solid bismuth is less dense than the liquid. As a result, molten bismuth does not shrink when it solidifies in molds, and so it is used to make low-temperature castings. 

The low melting point of bismuth and its alloys is exploited in fire sprinklers. 

The brittle, silvery, shiny metal was long considered the last stable element of the Periodic Table. In 2003 it was unmasked as an extremely weak alpha emitter (half-life 20 billion years). Like thulium, there is only one isotope. Bismuth alloys have low melting points (fuses, fire sprinklers). As an additive in tiny amounts, it imparts special properties on a range of metals. Applied in electronics and optoelectronics. The oxichloride (BiOCl) gives rise to pearlescent pigments (cosmetics). As bismuth is practically nontoxic, its compounds have medical applications. The basic oxide neutralizes stomach acids. A multitalented element. Crystallizes with an impressive layering effect (see right). 

The low-melting-point (157 °C), silver metal is mainly used in alloys to decrease the melting point. Combined with tin, lead, and bismuth to produce soldering metal for wide temperature ranges. The element is highly valuable in the electronics age as its unique properties are ideal for solar cells, optoelectronics, and microwave equipment. The arsenide is used in lasers and is also suitable for transistors. ITO (indium tin oxide) is a transparent semiconductor with wide application in displays, touchscreens, etc. In the household, indium as an additive prevents the tarnishing of silverware. Some electronic wristwatches contain indium batteries. 

Alloys are mixtures of metals combined to obtain specific characteristics and enhanced properties for a particular application. The term fusible metals or fusible alloys denotes a group of alloys that have melting points below that of tin (232°C, 449°F). Most of these substances are mixtures of metals that by themselves have relatively low melting points, such as tin, bismuth (m.p. 275°C), indium (157°C),... 

Thin foils rather than wires were used in the two following investigations. The 7S of zirconium at a temperature near the melting point appeared65 to be 1850 240 dyn/cm. For a copper containing traces of bismuth, 7S = 1350 erg/cm2 was found66. ... 

Wood s metal is another alloy that contains about 12.5% cadmium plus bismuth. It has a very low melting point of about 70°C, which makes it ideal for the fuse in overhead sprinklers in hotels and office buildings. Any fire will melt the trigger-like fuse, opening the valve to jettison water spray over the hot area that melted the Wood s metal alloy. 

Bismuth is the fifth element in the nitrogen group, and its properties are the most metal-like of the five. Elemental bismuth is a heavy, brittle, hard metal that can be polished to a bright gray-white coat with a pinkish hue. It is not found in this state very often because it is more likely to be combined with other metals and minerals, such as tin, lead, iron and cadmium. These are mixtures with low melting points, making them useful in fire-detection devices. 

Bismuth antimonide (BiSb) is not really a compound but single crystals of the alloy of bismuth and antimony. The crystals are used as semiconductors in the electronics industry and to produce type for printing presses and low-melting-point electrical fuses. 

Ununpentium is also known as eka-bismuth because it is homologous to the element bismuth located at the bottom of Group 15 (VA). Its melting point, boihng point, and density are unknown as are many of its other properties. Several isotopes of element 115 were produced by the nuclear reaction that bombarded calcium into a target americium, resulting in the fusion of the calcium nuclei with the americium nuclei to form isotopes of element 115 (ununpentium). 

At the beginning of the seventeenth century, 13 elements were known. Nine—carbon, sulfur, iron, copper, silver, gold, tin, lead, and mercury—had been discovered in ancient times. Four more—arsenic, antimony, bismuth, and zinc—were discovered between around 1250 and 1500. It is not by chance that 11 of the 13 are metals. Some of them have relatively low melting points and were undoubtedly first produced when fires were laid on surface ores. Fires built by preliterate peoples in modern times have often produced small quantities of metals. A rich vein of silver was discovered in this manner by an Indian sheepherder in seventeenth-century Peru who built a fire at nightfall and found the next morning that the stone under the ashes was covered with silver. 

Tin obtained above contains small amounts of impurities. It is purified by resmelting in a small reverberatory furnace at a temperature just above the melting point of tin. The molten tin is drawn out, separating iron, copper, arsenic, antimony, and other metals. Purified tin is further refined by boiling or polling processes to remove traces of impurity metals, such as lead and bismuth. 

Preparation of a Low-Melting Alloy. Put 0.5 g of cadmium, 0.05 g of tin, 1 g of lead, and 2 g of bismuth into a dry test tube. Heat the metal mixture until it melts and cool it. When the alloy solidifies, pour hot water into the test tube. What is observed At what temperature does the prepared alloy melt Note the melting point of the individual metals which the alloy is composed of. Explain the observed phenomenon. 

The physical properties of bismuth, summarized in Table 1, are characterized by a low melting point, a high density, and expansion on solidification. Thermochemical and thermodynamic data are summarized in Table 2. The solid metal floats on the liquid metal as ice floating on water. Gallium and antimony are the only other metals that expand on solidification. Bismuth is the most diamagnetic of the metals, and it is a poor electrical conductor. The thermal conductivity of bismuth is lower than that of any other metal except mercury. 

The electrical conductivity of a pure arsenic crystal has been measured 3 at temperatures down to 2-42° Abs. The resistance-temperature curve is similar to those of pure metals. There is evidence of definite residual resistance being maintained at low temperatures, but arsenic does not exhibit the abnormally high residual resistance shown by bismuth, nor does it show superconductivity. The resistance is by no means proportional to the absolute temperature. It has been estimated that the electrical resistance of liquid arsenic at the melting point is about 0-4 of that of the solid phase.4... 

TABLE 1. SOME REPRESENTATIVE LOW-MELTING-POINT ALLOYS CONTAINING BISMUTH... 

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