| heavy spar | <chemical> Native barium sulphate or barite, so called because of its high specific gravity as compared with other non-metallic minerals. Source: Websters Dictionary (01 Mar 1998) |
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| heavy water | most commonly used by cell biologists to stabilise microtubules. (18 Nov 1997) |
| immunoglobulins, heavy-chain | Major components of immunoglobulin molecules. They are the larger of the two types of polypeptide chains responsible for the biological and immunological properties of the different immunoglobulins. They differ according to the class of ig from which they were isolated, contain 450 to 600 amino acid residues per chain, and have molecular weights of 51-72 kD. One ig molecule comprises two heavy and two light chains. (12 Dec 1998) |
| active metal | <chemistry> Any very reactive metal, such as magnesium or sodium, most are located in the first two columns of the periodic table. (15 Jan 1998) |
| alkali earth metal | See: alkaline earth elements. (05 Mar 2000) |
| alkali metal | <chemistry> Any of the highly reactive metals (such as sodium or potassium) found in the first column of the periodic table, these metals act as bases. (13 Nov 1997) |
| Babbitt metal | An alloy of antimony, copper, and tin; used occasionally in dentistry. (05 Mar 2000) |
| base metal | A metal that is readily oxidised; e.g., iron, copper. (05 Mar 2000) |
| bell metal | A hard alloy or bronze, consisting usually of about three parts of copper to one of tin; used for making bells. Bell metal ore, a sulphide of tin, copper, and iron; the mineral stannite. Source: Websters Dictionary (01 Mar 1998) |
| rare earth metal | Those elements with atomic numbers 57-71 which closely resemble one another chemically and were once difficult to separate from one another. Synonym: rare earth elements. Origin: Lanthanum, first element of the series (05 Mar 2000) |
| central metal ion | <chemistry> The metal ion to which the ligands are attached at the centre of a coordination complex. (09 Oct 1997) |
| void metal composite | A porous metal structure that enables tissue growth within the openings to establish long-term attachment between prosthesis and tissue. (05 Mar 2000) |
| respiratory metal | A metal present in certain respiratory pigments; e.g., iron, manganese, copper, vanadium. (05 Mar 2000) |
| ceramo-metal casting | A casting made of alloys containing or excluding precious metals, to which dental porcelain can be fused. (05 Mar 2000) |
| metal | 1. <chemistry> An elementary substance, as sodium, calcium, or copper, whose oxide or hydroxide has basic rather than acid properties, as contrasted with the nonmetals, or metalloids. No sharp line can be drawn between the metals and nonmetals, and certain elements partake of both acid and basic qualities, as chromium, manganese, bismuth, etc. Popularly, the name is applied to certain hard, fusible metals, as gold, silver, copper, iron, tin, lead, zinc, nickel, etc, and also to the mixed metals, or metallic alloys, as brass, bronze, steel, bell metal, etc. 2. Ore from which a metal is derived; so called by miners. 3. A mine from which ores are taken. "Slaves . . . And persons condemned to metals." (Jer. Taylor) 4. The substance of which anything is made; material; hence, constitutional disposition; character; temper. "Not till God make men of some other metal than earth." (Shak) 5. Courage; spirit; mettle. See Mettle. The allusion is to the temper of the metal of a sword blade. 6. The broken stone used in macadamizing roads and ballasting railroads. 7. The effective power or calibre of guns carried by a vessel of war. 8. Glass in a state of fusion. 9. The rails of a railroad. <mathematics> Base metal, an alloy resembling brass, consisting of three parts of copper to one of zinc; also called Prince Rupert's metal. Origin: F. Metal, L. Metallum metal, mine, Gr. Mine; cf. Gr. To search after. Cf. Mettle, Medal. Source: Websters Dictionary (01 Mar 1998) |