Element Sulphur, S, Non Metal
|The solid, yellow, easily fusible and combustible substance well known by the name of sulphur, is an element in almost the pure state. It occurs fairly widely distributed in nature in the form of elongated octahedral crystals of a honey-yellow colour. The occurrence of sulphur is especially connected with volcanic phenomena. The whole consumption of sulphur in Europe has for a long time been supplied by Sicily. At the present day large quantities of free sulphur are also obtained from compounds of sulphur which are exceedingly abundant in nature. |
This element has been known since remote ages of antiquity on account of its occurrence in nature in the free condition. By the alchemists it was regarded as a constituent of many metals, and it was not until Lavoisier's investigations and his explanation of the process of combustion that sulphur was recognised as an elementary substance. In the pre-phlogistic period it was regarded by some as an essential constituent of combustible substances. Its common name brimstone was in Middle English "bernston" or "brenston" indicating a combustible mineral; sulfur is the old Latin name for the substance.
|Sulphur is widespread in nature, although in the free state it is more or less localised. The quantity present in the upper layer of the earth's surface has been estimated at 0.04 per cent. Indications have also been obtained of its existence in the sun, some of the hotter stars and in gaseous nebulae. |
In the free or "native" condition sulphur occurrence in volcanic districts is high, for example in Sicily, Italy, Louisiana, Mexico, Texas and Alaska; smaller quantities occur in Japan, Greece, Austria, Hungary, Germany, France, Spain and elsewhere. The element occurs sometimes in well-formed crystals, but more commonly is mixed with other mineral matter such as calcium sulphate (gypsum), strontium sulphate (celestine) and rock salt. An orange-red variety of native sulphur peculiar to Japan owes its colour to the presence of small quantities of tellurium and selenium, whilst a black pyritic sulphur containing traces of carbon occurs in Mexico and South Spain, in the latter case being found in fantastic fountain-like formations.
In all probability the history of the formation of many of these deposits of sulphur is that large masses of iron pyrites, having undergone thermal decomposition in the earth with formation of sulphur and ferrous sulphide, have subsequently been exposed to the action of steam; the ferrous sulphide has thus given rise to hydrogen sulphide which, issuing with the volcanic gases, has become oxidised with formation of free sulphur. If the oxidation of the hydrogen sulphide had proceeded further, sulphuric acid would have been produced, which by its action on the calcareous rocks would account for the frequent contamination of the sulphur with sulphates. It is possible, however, that in some cases the deposits of sulphur owe their existence to the decomposition of pre-existing mineral sulphates.
Hydrogen sulphide is present in many mineral springs, and even free sulphur is occasionally found therein. Many metallic sulphides, for example, iron pyrites, galena, zinc blende, stibnite and cinnabar, occur abundantly. Sulphur dioxide, sulphites, sulphuric acid and sulphates are also found in nature, more especially in waters springing from volcanic earth, whilst the sulphates of certain metals such as calcium, barium and magnesium exist in large deposits.
In the organic world sulphur is sometimes found free; certain micro-organisms and algae which thrive in water containing hydrogen sulphide enclose sulphur in a non-crystalline condition. Combined sulphur occurrence albuminoid substances, and is therefore found in all living animal and vegetable matter. The presence of sulphur in coal in various forms is well known. Certain essential oils such as those derived from mustard and garlic contain combined sulphur, as also do petroleum and asphaltum in small and variable quantity.