alkaline-earth metals

alkaline-earth metals,

metals constituting Group 2 of the periodic tableperiodic table,
chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley. In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the table entitled
..... Click the link for more information. . Generally, they are softer than most other metals, react readily with water (especially when heated), and are powerful reducing agents, but they are exceeded in each of these properties by the corresponding alkali metal. They form divalent compounds. In order of increasing atomic number the alkaline-earth metals are berylliumberyllium
[from beryl ], metallic chemical element; symbol Be; at. no. 4; at. wt. 9.01218; m.p. about 1,278°C;; b.p. 2,970°C; (estimated); sp. gr. 1.85 at 20°C;; valence +2.
..... Click the link for more information. , magnesiummagnesium
, metallic chemical element; symbol Mg; at. no. 12; at. wt. 24.3050; m.p. about 648.8°C;; b.p. about 1,090°C;; sp. gr. 1.738 at 20°C;; valence +2. In 1808, Sir Humphry Davy discovered magnesium in its oxide, although it is not certain that he isolated the
..... Click the link for more information. , calciumcalcium
[Lat.,=lime], metallic chemical element; symbol Ca; at. no. 20; at. wt. 40.078; m.p. about 839°C;; b.p. 1,484°C;; sp. gr. 1.55 at 20°C;; valence +2. Calcium is a malleable, ductile, silver-white, relatively soft metal with face-centered, cubic crystalline
..... Click the link for more information. , strontiumstrontium
[from Strontian, a Scottish town], a metallic chemical element; symbol Sr; at. no. 38; at. wt. 87.62; m.p. 769°C;; b.p. 1,384°C;; sp. gr. 2.6 at 20°C;; valence +2.
..... Click the link for more information. , bariumbarium
[Gr.,=heavy], metallic chemical element; symbol Ba; at. no. 56; at. wt. 137.327; m.p. 725°C;; b.p. 1,640°C;; sp. gr. 3.5 at 20°C;; valence +2. Barium is a soft, silver-white, chemically active, poisonous metal with a face-centered cubic crystalline structure.
..... Click the link for more information. , and radiumradium
[Lat. radius=ray], radioactive metallic chemical element; symbol Ra; at. no. 88; mass number of most stable isotope 226; m.p. 700°C;; b.p. 1,140°C;; sp. gr. about 6.0; valence +2. Radium is a lustrous white radioactive metal.
..... Click the link for more information. .

alkaline-earth metals

[¦al·kə‚līn ′ərth ′med·əlz]

(chemistry)

The heaviest members of group 2 in the periodic table; usually calcium, strontium, magnesium, and barium.

References in periodicals archive ?

In simpler words, they're solids with a relatively open, three-dimensional crystal structure built from the elements aluminum, oxygen, and silicon, with alkali or alkaline-Earth metals (such as sodium, potassium, and magnesium) plus water molecules trapped in the gaps between them.

Global Zeolite Market 2018 Industry Key Players, Trends, Sales, Supply, Demand, Analysis & Forecast to 2024

Among the plans that will be investigated by the researchers in the near future, mention can be made of the addition of various percentages of alkali and alkaline-earth metals as promoter on this catalyst and studying their effect on steam reforming of methane and also on dry reforming of methane.

Production of Catalyst for Steam Reforming of Methane

Contributors from Europe and South Africa provide background on ferroalloy basics, thermodynamics, the kinetics of reduction and general processing issues, electric furnace operations, environmental issues, and other general topics, followed by the theory and technology of ferroalloys with silicon, manganese, high carbon, and chromium, and minor ferroalloys like ferronickel, tungsten, molybdenum, vanadium, niobium, titanium, zirconium, boron, and rare-earth and alkaline-earth metals. Each includes information on the element and its properties, reactions, and equilibria with other major relevant elements, as well as raw materials for it and methods of preparation, smelting techniques, and processing details.

Handbook of ferroalloys; theory and technology

Alkaline and alkaline-earth metals compounds as catalysts for the methanolysis of sunflower oil.

Transesterification of used frying oil using calcium oxide as heterogeneous catalyst

Fluorides and chlorides of alkaline and alkaline-earth metals are used as additions, which enable improvement of various technological and metallurgical properties of the flux (Table 1), whereby one of the main requirements to fluxes for electroslag welding (ESW) and electroslag remelting (ESR) of titanium is complete absence of oxides, because presence in flux even in small amounts of such stable oxides as [Al.sub.2][O.sub.3], ZrO and Ti[O.sub.2] does not exclude possibility of titanium contamination by oxygen [2-3].

Electroslag melting of halogenide oxygen-free fluxes

The continental biosphere has greatly speeded up the rate of erosion of the surfaces of the continents and has given it special characteristics: increase in the pressure of CO2 in the soil and the addition of organic acids and speeding up the decomposition of silicates, all of which lead to the liberation of silica and alkaline-earth metals.

Microscopic jewelery

Oxide cathodes of that time represented a mixture of oxides of such alkaline-earth metals as calcium, strontium and barium.

When designing oxide cathode for welding electric arc we proceeded from the fact that the best base is destoichiometrized Zr[O.sub.2], and the best emission additives are oxides of alkaline-earth metals. As far as the technology itself of producing mixtures of these two components is concerned, we used for this purpose powder metallurgy.