Brittle tin

There are two allotropes of tin. One is known as gray or alpha (a) tin, which is not very stable. The other is known as white tin or beta ((3), which is the most common allotrope. The two forms (allotropes) of tin are dependent on temperature and crystalline structure. White tin is stable at about 13.2°C. Below this temperature, it turns into the unstable gray alpha form. There is also a lesser-known third allotrope of tin called brittle tin, which exists above 161°C. Its name is derived from its main property. 

Tin is a soft, silvery metal with a slight bluish color. Metallic tin has three forms that exist at different temperatures. At temperatures above 13.2 °C, the stable form has metallic properties, and it is known as white tin. When tin is heated above 161 °C, the white form is converted to a form known as brittle tin. This form does not behave as a metal, and it fractures when struck with a hammer. The form of tin that is stable below 13.2 °C is known as gray tin because it is easily crumbled to yield a gray powder. Even at temperatures below 13.2 °C, this transformation from the white form to the gray form is very slow unless the temperature is approximately -50 °C. The crumbling of gray tin (the low temperature form) is known historically as tin disease or tin pest. ... 

Cu), solder (33% Sn and 67% Pb), and pewter (85% Sn, 7% Cu, 6% Bi, and 2% Sb). Tin exists as three allotropes white tin, stable at normal temperatures gray tin, stable at temperatures below 13.2°C and brittle tin, found at temperatures above 161°C. When tin is exposed to low temperatures, it gradually changes to powdery gray tin and crumbles away this is known as tin disease. 

Elemental tin has an atomic number of 50, an atomic mass of 118.69, and exists in three allotropic forms white tin at room temperature, nonmetallic gray tin at <13.3°C, and brittle tin at >161°C. White tin is a stable silver-white, lustrous, soft metal with a density of 7.27, a melting point of 231.9°C, and a boiling point of 2507°C. Tin has 10 stable isotopes ( Sn, Sn, Sn, Sn, Sn, Sn, Sn, °Sn, Sn, and " Sn), the most for any element. Inorganic tin compounds exist in the +2 (stannous) and +A (stannic) oxidation states. Stannous compounds are generally more polar than stannic compounds, are unstable in dilute aqueous solutions, are easily oxidized, and normally contain some Sn+". Stannic oxide occurs naturally as the mineral cassiterite, has a melting point of 1127°C, and has wide application in industry. 

D. Muller, Y.R. Cho, E. Fromm, Adhesion strength of ductile aluminum and brittle TIN coatings on steel, aluminum and copper, measured by fracture mechanics tests. Surf. Coat. Technol. 74/74 (1995) 849. 

Of historic interest is the question of the existence of a high-temperature form of tin with a transformation temperature at 161 °C. This form of tin was said to have a rhombic crystal structure and called gamma or brittle tin. It has been demonstrated that this form of tin does not exist. It has been established that tin exists as the two polymorphic forms, gray tin (alpha) with a diamond cubic crystal structure up to 13.2°C, which transforms to white tin (beta) with a body-centered tetragonal crystal structure up to the melting temperature (232°C). 

The alloy niobium titanium (NbTi) and the intermetaUic compound of niobium and tin (Nb.3 Sn) are the most technologically advanced LTS materials presently available. Even though NbTi has a lower critical field and critical current density, it is often selected because its metallurgical properties favor convenient wire fabrication. In contrast, Nb.3Sn is a veiy brittle material and requires wire fabrication under very well-defined temperature conditions. 

Hydraulic piston-type compactors for collection vehicles, on-site compactors, and transfer-station compactors roll crushers used to fracture brittle materials and to crush tin and aluminum cans and other ductile materials... 

In cold climates, metallic tin (solid 11) slowly changes to solid 1. (Solid phase transitions are often slow.) The change from a shiny metallic surface to a brittle and llaky grey surface is known as tin disease. 

Organotin compounds are important industrial chemicals. One major use is as stabilizers for poly(vinyl chloride) (PVC) plastics. These additives, one example of which is dioctyltinmaleate, inhibit degradation of the polymer by heat, light, and oxygen. In the absence of these tin compounds, PVC yellows and becomes brittle. 

Semimetal that occurs as a tin-type, brittle form and as a yellow, unstable, nonmetallic form. Its main use is in alloys to harden other metals. Without the addition of antimony, lead would have remained the "softy" of the Periodic Table. But with antimony, lead ruled the print world and later found use in the production of rechargeable batteries. It can be found in older ceramic glazing (yellow orange). Everyday encounters antimony sulfide in match heads and red rubber, antimony oxide is used as a flame retardant. Pure antimony is starting to become of interest in the electronics sector. 

The Aiiotropes of Tin Tin Pest. Metallic tin may occur in three allotropic forms (see Textbox 19) the common form of tin, also known as white tin or beta tin, is stable at ambient temperatures its stability extends between -18°C and 170°C below -18°C tin is converted to a gray powdery allotrope, known as alpha tin or tin pest. A third allotrope, known as rhombic tin, is the form of tin stable at temperatures above 170°C. If ordinary white tin remains for extended periods of time at temperatures below -18°C, therefore, it is slowly converted to the gray, brittle, and powdery allotrope tin pest the conversion is accelerated at still lower temperatures. Tin objects kept in regions of the world where extremely low temperatures (below -18°C) prevail, initially... 

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. 

In electronic applications, where it is common to deposit copper and/or copper alloy and tin in sequence, with a nickel diffusion barrier layer, 0.5 fim thick, between the layers present, no failure occurs. Without the nickel layers between bronze/-copper/tin layers themselves, for instance, intermetaUic brittle layer(s) and Kirkendall voids are formed, leading eventually to separation of the coated system and substrate. 

French nobleman Claude Geoffroy, the Younger White, brittle metal often found with copper, tin, and lead its alloy, called Wood s metal, has a low boiling point making it useful in triggering fire alarms. 

Platinum occurs in nature as a bright-white cubic crystalline solid with metallic luster associated with other noble metals of its group. Platinum also occurs as the mineral sperrylite, PtAs2, found as tin-white brittle cubic crystals containing 52-57% platinum in certain nickel-bearing deposits. Some other minerals of platinum are cooperite PtS (Pt 80-86%) and braggite(Pt, Pd, Ni)S (Pt 58-60%). The abundance of platinum in the earth s crust is estimated to be 0.005 mg/kg. 

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