Strontium binary compounds

In 1817 Dobereiner found that if certain elements were combined with oxygen in binary compounds, a numerical relationship could be discerned among the equivalent weights of these compounds. Thus when oxides of calcium, strontium, and barium were considered, the equivalent weight of strontium oxide was approximately the mean of those of calcium oxide and barium oxide. The three elements in question, strontium, calcium, and barium were said to form a triad. 

Self-Test C.3B Write the formula of the binary compound formed by (a) lithium and nitrogen (b) strontium and bromine. 

A substance is considered soluble if more than three grams of the substance dissolves in 100 ml of water. The more common rules are listed below. 1. All common salts of the group 1A elements and ammonium ions are soluble. 2. All common acetates and nitrates are soluble. 3. All binary compounds of group 7A elements (other than F) with metals are soluble except those of silver, mercury(l), and lead. 4. All sulfates are soluble except those of barium, strontium, lead, calcium, silver, and mercury(l). 5. Except for those in Rule 1, carbonates, hydroxides, oxides, sulfides, and phosphates are insoluble. ... 

M2F2-Srp2 (M = Li, Na, K). All three binary systems are the simple eutectic. Also in the same series of strontium chlorides, there are only simple eutectic systems for lithium, sodium, and potassium, but systems containing bigger rubidium and cesium cations with low polarization ability already form binary compounds. 

Magnesium, calcium, strontium, and barium do not react with tungsten, and no binary compounds are known. The solubility of tungsten in the respective molten metal is very low. 

When a metal cation and a non-metal anion form a compound, they are called metal-non-metal binary compounds. Metals with ions of only 1+, 2+, or 3+ charges in groups I A, II A, and III A are called monoatomic, diatomic and polyatomic ions respectively. Lithium, potassium, and cesium all have a 1+ charge. Beryllium and strontium, in group IIA, are named with the same rules. However, when you name elements in groups IVA-VIIA, where anions of-1, —2, or -3 anions are formed, then ide is added to the name. 

For the binary alkaline earth sihcide SiSr, two different structures have been reported. One contains one-dimensionally extended zigzag chains beside isolated Si" atoms [73]. Schafer et al. prepared a modification with the same composition, which instead contained isolated sUicide units of ten atoms. In these units, planar hexagons are substituted in the 1-, 2-, 4-, and 5-ring positions by four additional Si atoms. An isostructural compound was found for germanium as well, but showing defects in this unit in the positions 1, 2, 4, and 5. Both materials could not be obtained from stoichiometric approaches, and their formation obviously is coupled to strontium excess [69] (Fig. 3). 

It has been shown that the f.p. curves of binary mixtures of the alkali chlorides show the probable formation of compounds, LiCl.RbCl, LiCl.CsCl, and LiC1.2CsCl. The curves of binary mixtures of lithium chloride with magnesium, calcium, strontium, or barium chloride show no signs of the formation of definite compounds,... 

The Binary System Silver-Strontium. A somewhat more complicated binary system, that formed by silver and strontium, is represented in Figure 24-7. It is seen that four intermetallic compounds are formed, their formulas being Ag Sr, Ag5Sr3, AgSr, and Ag Srg. These compounds and the pure elements form a series of eutectics for example, the alloy containing 25 weight percent strontium is the eutectic mixture of Ag Sr and AggSr. ... 

FIG. 24-7. Phase diagram for the binary system silver-strontium, showing the formation of four intermetallic compounds. 

The production of metal fullerides succeeds as well with alkaline earth metals and rare earth elements. Among others, there are mixed alkali/alkaline earth fullerides with a composition of M3, eBaxQo (0.2 < x < 2 M = K, Rb, Cs). Likewise may pure alkaline earth fullerides be obtained, for example, CasCGo that becomes a supraconductor below 8.4 K. Barium and strontium give binary fullerides too, but with stoichiometric factors of 3, 4, and 6. Ytterbium and samarium may intercalate in the C,so-crystal as well, yielding supraconductive compounds with a composition of M2.75C1S0. 

A somewhat more complicated binary system —that formed by silver and strontium —is represented in Figure 17-8. It is seen that four intermetallic compounds are formed, their formulas being AgsSr, AgjSr.-, AgSr, and... 

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