With Group IIA metals

Lactose has been shown to combine with many cations in a 1 1 ratio, and equilibrium constants have been calculated (Swartz et al. 1978). No complexing could be demonstrated with K+ or NH4+. Detailed studies with group IIA metal chlorides demonstrated 97% recovery of lactose with calcium (Quickert and Bernhard 1982). 

In the reaction of gaseous hydrogen halacids HX with group IIA metals, M, the dihalides, MX2 are formed at elevated temperatures ... 

C,H3)3PbPb(C,H3)3 Reaction with RMgX 5.4.7.2.2 Reaction with group-IIA metals ... 

Reaction with Sr metal 5.4.7.1.1 Reaction with group-IIA metals 5.4.7.1.3... 

Group IIA metals inelude Be, Mg, Ca, Sr, Ba and Ra whieh are grey, moderately-hard, high melting-point substanees. Like the alkali metals they attaek water to liberate hydrogen but with less vigour. The salts of the alkaline earths are generally less stable towards heat and water than those of alkali metals, and less water soluble. 

The decomposition of dolomite shows many points of similarity with the reactions of calcite and of other single carbonates of Group IIA metals (Sects. 3.1.1 and 3.1.2) the reaction is reversible, occurs at an interface, and both apparent kinetic parameters and reactivity are influenced by the prevailing C02 pressure. 

The binary mixtures lack miscibility in the liquid and solid states with any of the group-IIA metals or with the heavier group-IA metals, K, Rb and Cs (Fig. 1). There is, however, a progressive increase in the miscibility of Li and Na with the group-IIA metal as the atomic number of the latter increases. This is accompanied by compound formation Li with Ca, Sr and Ba, and Na with Sr and Ba " . 

Typically, Be-containing alloys and intermetallic phases have been prepared in beryllia or alumina crucibles Mg-containing products have been synthesized in graphite, magnesia or alumina crucibles. Alloys and compounds containing Ca, Sr and Ba have been synthesized in alumina , boron nitride, zircon, molybdenum, iron , or steel crucibles. Both zircon and molybdenum are satisfactory only for alloys with low group-IIA metal content and are replaced by boron nitride and iron, respectively, for group-IIA metal-rich systems . Crucibles are sealed in silica, quartz, iron or steel vessels, usually under either vacuum or purified inert cover gas in a few cases, the samples were melted under a halide flux . 

For most atoms, the addition of an electron occurs with the release of energy, so the value of AE is negative. There are some exceptions, most notably the noble gases and group IIA metals. These atoms have completely filled shells, so any additional electrons would have to be added in a new, empty shell. Nitrogen also has virtually no tendency to accept an additional electron because of the stability of the half-filled outer shell. 

The oxides of the group IIA metals are ionic, so they react with water to produce the hydroxides. 

Most oxides (O2-) are insoluble except for those of Group IA and Group IIA metals, which react with water. (These will produce strong bases.)... 

The group IIA metals have the outer electron configuration ns2 with no singly occupied orbital for bonding. The structures are hep for Be and Mg and ccp for Ca and Sr. The structures are bcc for Ba and Ra, for which promotion to (n — l)d1ns1 is more favorable than for the other metals of the family. Metals with filled or nearly filled orbitals (Co, Ni, Pt metals, Cu family, Zn, and Cd) have ccp (3P) or hep (2P) structures. 

At least part of the stabilization of the compounds containing the diatomic anions 022- and 02 comes from the fact that crystal lattices are most stable when the cations and anions have similar sizes (see Chapter 5). The Group IIA metals give normal oxides except for barium and radium, which give peroxides when they react with oxygen ... 

Reactions of Rb and Cs with oxygen also give superoxides. Group IIA metals follow a similar pattern. Be, Mg, Ca, and Sr give normal oxides, and Ba gives predominantly the peroxide. Apparently, Ra gives either a peroxide or some superoxide depending on the reaction conditions. 

Both normal sulfite (containing S032-) and acid sulfite or bisulfite (containing HS03 ) salts exist, with salts of the Group IA and Group IIA metals being most common. The... 

Bromine is found as the bromide salts of Group IA and Group IIA metals, usually along with the chlorides. Bromine and iodine are also found in compounds contained in brines and seawater. A few minerals (e.g., lautorite, Ca(I03)2) are also known that contain iodine, and it is found in plants and animals from the sea. 

Ternary silicides with the group-IIA metals are known, e.g., the (Ca, Sr)Si2 phases. Although A1 and Si do not form compounds, the addition of other metals can result in industrially important ternary or multicomponent silicidese.g., AlFeSi, AlMnSi, AlCrSi, Ali3Cr4Si4, AljMgjFeSig, AlCuMgSi. 

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