calcium Chem.
(ˈkælsɪəm)
[f. (by Sir H. Davy) L. calx, calc(i)- lime, on the type of other names of metals in -um, -ium.]
1. A chemical element, one of the ‘metals of the alkaline earths’, being the basis of lime; though one of the most widely diffused of elements, it is found in nature only in composition, and was first separated by Davy in 1808, as a light yellow metal, ductile and malleable, about as hard as gold, which rapidly oxidizes in air containing moisture, and forms ‘quick-lime’. Symbol Ca.
| 1808 Sir H. Davy in Phil. Trans. XCVIII. 346, I shall venture to denominate the metals from the alkaline earths barium, strontium, calcium, and magnium. 1815 W. Phillips Outl. Min. & Geol. (ed. 3) 25 Lime has been proved by Sir H. Davy..to be a metallic oxide, consisting of 28 per cent. of oxygen and 72 of calcium. 1878 Huxley Physiogr. 81 A solid carbonate of calcium..more commonly termed carbonate of lime. 1881 Lockyer in Nature No. 614. 321/2 Those short common lines of calcium which for years past we had watched coming out of the salts of calcium when decomposition was taking place. |
2. attrib. = calcic; as in calcium compounds, salts, etc.; esp. calcium carbonate, CaCO3, carbonate of lime, or limestone, and arragonite; calcium chloride, CaCl2, chloride of lime, bleaching powder; calcium fluoride, CaFl2, fluor spar; calcium light, the lime-light; calcium oxide, CaO, quick-lime; calcium phosphate Ca3(PO4)2, phosphate of lime, the chief constituent of bone-ash; calcium silicate, CaSiO3, found crystallized in tabular spar, etc.; calcium sulphate, CaSO4, found crystallized as Gypsum.
| 1864 Daily Tel. 4 Oct., A blinding ray from a calcium light apparatus. 1869 Roscoe Elem. Chem. 154 When bones are burnt, a white solid mass is left behind; this is called Calcium Phosphate. 1872 Daily News 7 Nov., Calcium lights shone on smiling multitudes. 1873 Fownes Chem. 364 Calcium Carbonate is always precipitated. |