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The origin and usage of the term ''metalloid'' is convoluted. Its origin lies in attempts, dating from antiquity, to describe metals and to distinguish between typical and less typical forms. It was first applied to metals that floated on water (lithium, sodium and potassium), and then more popularly to nonmetals. Only recently, since the mid-20th century, has it been widely used to refer to elements with intermediate or borderline properties between metals and nonmetals. ==Pre-1800== Ancient conceptions of metals as solid, fusible and malleable substances can be found in Plato's ''Timaeus'' (c. 360 BCE) and Aristotle's ''Meteorology''.〔Cornford 1937, pp. 249–50〕〔Obrist 1990, pp. 163–64〕 More sophisticated classification arrangements were proposed by Pseudo-Geber (in the ''Geber corpus,'' c. 1310), Paracelsus (''De Natura Rerum libri nonem,'' 1525–6; and later works), Basil Valentine ''(Conclusiones,'' 1624), and Boerhaave ''(Elementa Chemiæ,'' 1733). They attempted to separate the more characteristic metals from substances having those characteristics to a lesser degree. Such substances included zinc, antimony, bismuth, stibnite, pyrite and galena. These were all then called semimetals or bastard metals.〔Paul 1865, p. 933〕〔Roscoe & Schorlemmer 1894, pp. 3–4〕〔Partington 1961, pp. 148, 192–193〕 In 1735 Brandt proposed to make the presence or absence of malleability the principle of this classification. On that basis he separated mercury from the metals. The same view was adopted by Vogel (1755, ''Institutiones Chemiæ)'' and Buffon (1785, ''Histoire Naturelle des Minéraux)''. In the interim, Braun had observed the solidification of mercury by cold in 1759–60. This was confirmed by Hutchins and Cavendish in 1783.〔Jungnickel & McCormmach 1996, p. 279–281〕 The malleability of mercury then became known, and it was included amongst the metals.〔 In 1789 Fourcroy〔Fourcroy, p. 380〕 highlighted the weakness of this distinction between metals and semimetals. He said it was evident from the fact that :between the extreme malleability of gold and the singular fragility of arsenic, other metals presented only imperceptible gradations of this character, and because there was probably no greater difference between the malleability of gold and that of lead, which was considered to be a metal, than there was between lead and zinc, which was classed among semi-metals, while in the substances intermediate between zinc and arsenic the differences were slight. This idea of a semimetal, as a brittle (and thereby imperfect)〔Craig 1849〕〔Roscoe & Schorlemmer 1894, pp. 1–2〕 metal, was gradually discarded after 1789 with the publication of Lavoisier's 'revolutionary' 〔Strathern 2000, p. 239〕 ''Elementary Treatise on Chemistry''.〔Roscoe & Schormlemmer 1894, p. 4〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Origin and use of the term metalloid」の詳細全文を読む スポンサード リンク
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