Elemental sulfur melting point

Tantalum is a gray, heavy, and very hard metal. When pure, it is ductile and can be drawn into fine wire, which is used as a filament for evaporating metals such as aluminum. Tantalum is almost completely immune to chemical attack at temperatures below ISOoC, and is attacked only by hydrofluoric acid, acidic solutions containing the fluoride ion, and free sulfur trioxide. Alkalis attack it only slowly. At high temperatures, tantalum becomes much more reactive. The element has a melting point exceeded only by tungsten and rhenium. Tantalum is used to make a variety... 

Sulfur is widely distributed as sulfide ores, which include galena, PbS cinnabar, HgS iron pyrite, FeS, and sphalerite, ZnS (Fig. 15.11). Because these ores are so common, sulfur is a by-product of the extraction of a number of metals, especially copper. Sulfur is also found as deposits of the native element (called brimstone), which are formed by bacterial action on H,S. The low melting point of sulfur (115°C) is utilized in the Frasch process, in which superheated water is used to melt solid sulfur underground and compressed air pushes the resulting slurry to the surface. Sulfur is also commonly found in petroleum, and extracting it chemically has been made inexpensive and safe by the use of heterogeneous catalysts, particularly zeolites (see Section 13.14). One method used to remove sulfur in the form of H2S from petroleum and natural gas is the Claus process, in which some of the H2S is first oxidized to sulfur dioxide ... 

An element is a substance that cannot be broken down into simpler substances by ordinary chemical means. A chemical compound is a substance made up of two or more elements that have been chemically bonded together. Scientists believe that solid sulfur compounds do not exist on Venus like they do on Earth because, at about 900° Fahrenheit (480° Celsius), the surface temperature on Venus is too hot for them to form in the first place. This temperature is well above the melting point of sulfur (235°F [ 113°C]). Therefore, instead of being incorporated into rocks, the sulfur on Venus continues to float around in the atmosphere in the form of the chemical compound sulfur dioxide (S02). 

Cesiums boihng point is 669.3°C and its density is 1.837 g/cm. Mercury is the only metal with a lower melting point than cesium. It is extremely dangerous when exposed to air, water, and organic compounds or to sulfur, phosphorus, and any other electronegative elements. It must be stored in a glass container containing an inert atmosphere or in kerosene. 

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. 

The IR spectrum of the complex in cyclohexane solution is characterized by the three strong bands in the carbonyl region at 2083(m), 2042(s), and 2006(s)cm-1. The most common impurities are elemental sulfur and Fe3S2(CO)9 [vco(hexanes) = 2062(s), 2043(s), 2024(m) cm"1]. The melting point is 46°C. The compound is thermally unstable above room temperature. It can be purified by vacuum sublimation at room temperature. 

Sulfur is a yellow non-metallic element. It is found in Group VI of the Periodic Table. It is a brittle, non-conducting solid with a fairly low melting point (115°C). Sulfur will not dissolve in water but will dissolve in solvents such as carbon disulfide and methylbenzene (toluene). Like carbon, sulfur has allotropes. Its main allotropes are called rhombic sulfur and monoclinic sulfur (Figure 12.1). 

TT7e can follow the history of sulfur back to the days of Sodom and Gomorrah. Nowadays, sulfur is a cheap material which is available in enormous quantities industrially in a purity that is exceptionally high for an element. Only a negligibly small proportion of this production is used directly as the element mainly because we still know and understand far too little about the properties of sulfur to be able to change them to meet selected practical ends. For example, scientists still dipute the melting point of sulfur. 

In a leaching reaction where elemental sulfur is one of the by-products, it becomes important to carry out the reaction at temperatures below the melting point of monoclinic sulfur (119°C). Liquid sulfur will prevent the reactions of the other constituents in the aqueous phase. 

The Frasch method is based on the low melting point of sulfur. The element melts at a temperature slightly higher than that of boiling water (212°F/1(X)°Q. Here is how the method works ... 

M 284.4, m 160 . It crystallises from CgH6 in yellow plates or from hot trichlorobenzene. The low melting point reported in the literature (112° with gradual softening at 68-102°) has been attributed to the presence of elemental sulfur in the crystals. It has a foul odour and is a suspected carcinogen. [Yousif et al. Tetrahedron 40 2663 1984, Scott et al. J Org Chem 22 789 7957.]... 

Elemental bismuth is inert in dry air at room temperature, but oxidizes slowly to become covered with a thin film of the oxide, which gives it a beautiful multi-colored luster. Above its melting point, it oxidizes rapidly to form an oxide film. At red heat in air, it bums with a bluish flame to give a yellow fume of bismuth oxide (BiiOj). It can also be attacked by super-heated water vapor to form the yellow oxide. Heating with sulfur produces bismuth sulfide Bi2S3 as a dark brown to grayish black solid. 

Between 400 and 430° the hydrogen pressure reaches 1 atm. The melting point (under pressure) is above 800°. Sodium hydride dissolves in fused sodium hydroxide and in fused alkali halides. It is insoluble in liquid ammonia. Water decomposes it immediately and completely to hydroxyl ion and hydrogen. Although sodium hydride is said to be stable in dry oxygen to 230°, traces of elemental sodium present may cause its ignition at lower temperatures. Copper, lead, and iron oxides are reduced by the compound to the free metals. Sulfur dioxide, carbon monoxide, and the halogens are reduced by the hydride to dithionite, formate, and halide ions, respectively. 

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