Group 2 elements binary compounds

The elements of all other groups form binary compounds with scandium. The number of binary compoxmds in each system is indicated in table 1 (above). Within each large period Sc forms the largest number of binary compounds with 8A and 3B elements. In the rows of the p-elements the number of binary compoimds decreases with the increase of the group number of the element. The number of binary compounds changes inconsiderably with the increase of the period s number. 

Nitrogen does form a number of binary compounds with the halogens but none of these can be prepared by the direct combination of the elements and they are dealt with below (p. 249). The other Group V elements all form halides by direct combination. 

A. S. Bere2hnoi, Silicon and its Binary Systems Consultants Bureau, New York, 1960 J. W. MeUor,H Comprehensive Treatise on Inof anic and Theoretical Chemisty Vol. IV, Longmans, Green Co., Inc., New York, 1957 M. C. Sneed and R. C. Brasted, eds.. Comprehensive Inorganic Chemisty Vol. VII The Elements and Compounds of Group IPH, D. Van Nostrand Co., Inc., Princeton, N.J., 1958. 

The binary compounds of the Group 13 metals with the elements of Group 15 (N, P, As, Sb, Bi) are stmcturally less diverse than the chalcogenides just considered but they have achieved considerable technological application as III-V semiconductors isoelectronic with Si and Ge (cf. BN isoelectronic with C, p. 207). Their stmctures are summarized in Table 7.10 all adopt the cubic ZnS stmcture except the nitrides of Al, Ga and In which are probably more ionic (less covalent or metallic) than the others. Thallium does not form simple compounds... 

Nitrogen forms binary compounds with almost all elements of the periodic table and for many elements several stoichiometries are observed, e.g. MnN, Mn Ns, Mn3N2, MniN, Mn4N and Mn tN (9.2 < jc < 25.3). Nitrides are frequently classified into 4 groups salt-like , covalent, diamond-like and metallic (or interstitial ). The remarks on p. 64 concerning the limitations of such classifications are relevant here. The two main methods of preparation are by direct reaction of the metal with Ni or NH3 (often at high temperatures) and the thermal decomposition of metal amides, e.g. ... 

The halides are binary compounds of a halogen (elements of group Vllb of the periodic table) and a more electropositive element such as a metal. 

The chalcogenides are binary compounds of a chalcogen (i.e., the elements of Group Ilb zinc, cadmium, mercury) with a less electropositive element, such as those of Group VIb (oxygen, sulfur, selenium, and tellurium). This section covers the sulfides, selenides, andtellurides. Oxides are reviewed above in Ch. 11. Most of the chalcogenides have useful optical characteristics and their applications are usually found in optics. 

Halogens, the elements in Group 17 of the periodic table, have the largest electron affinities of all the elements, so halogen atoms (a n readily accept electrons to produce halide anions (a a. This allows halogens to react with many metals to form binary compounds, called halides, which contain metal cations and halide anions. Examples include NaCl (chloride anion), Cap2 (fluoride anion), AgBr (bromide anion), and KI (iodide anion). 

A major and growing use of the minor metalloids is in semiconductor fabrication. Germanium, like silicon, exhibits semiconductor properties. Binary compounds between elements of Groups 13 and 15 also act as semiconductors. These 13-15 compounds, such as GaAs and InSb, have the same number of valence electrons as Si or Ge. The energy gap between the valence band and the conduction band of a 13-15 semiconductor can be varied by changing the relative amounts of the two components. This allows the properties of 13-15 semiconductors to be fine-tuned. 

Silicon-containing ceramics include the oxide materials, silica and the silicates the binary compounds of silicon with non-metals, principally silicon carbide and silicon nitride silicon oxynitride and the sialons main group and transition metal silicides, and, finally, elemental silicon itself. There is a vigorous research activity throughout the world on the preparation of all of these classes of solid silicon compounds by the newer preparative techniques. In this report, we will focus on silicon carbide and silicon nitride. 

Most nonmetallic elements will react with the group IA and IIA metals to give binary compounds. Heating the metals with nitrogen or phosphorus gives nitrides and phosphides of the metals. 

This review has described the synthesis, structure and reactivity of important classes of group 13/15 compounds such as Lewis acid base adducts and heterocycles. In addition, their potential to serve as single source precursors for the deposition of the corresponding binary materials by MOCVD process has been demonstrated. Because of the large number of compounds containing the lighter elements of group 15, N, P and As, these... 

All binary compounds of Group 17 (VIIA) elements (other than F) with metals are soluble except those of silver, mercury (I), and lead. 

As already suggested and discussed by several authors, such as Pettifor (1984, 1986), Villars etal. (1989), etc., these maps highlight a regular trend in the formation of binary compounds. In the lower-left corner of the map those systems are represented obtained by combinations among elements of the first four groups of the Periodic Table. 

Figure 5.21. Y Nb, Ta binary alloys. The dashed boxes show the metals which, at least at high temperature, form one continuous range of solid solutions with the 5th group elements. In the systems marked by an asterisk intermediate compounds are formed (with or without a continuous solid solution).

Figure 5.39. Compound formation capability in the binary alloys of the 15th group elements.

A few notes about simple binary compounds of the 16th group elements. The reduced intermetallic character of these compounds is possibly reflected in... 

Selenides, tellurides andpolonides. Se, Te and Po react easily with most metals and non-metals to form binary compounds (selenides and tellurides are common mineral forms of these elements). Non-stoichiometry is frequently observed in the compounds with the transition elements many of these compounds may be described as metallic alloys. The compounds of the metals of the first two groups may be considered the salts of the acids H2Se, H2Te, etc. The alkali metal selenides... 

Some members of this group of elements are readily oxidised with more or less violence dependent upon the oxidant and conditions of contact. Individually indexed elements (and some binary compounds) are ... 

Structural units of binary polycompounds with main group elements consist of one-, two- and three-dimensional polymers, as well as cage-like polycyclic anions. These polyanions can be converted into molecular compounds by appropriate chemical reactions. 

The electropositive elements form series of solid binary compounds with the main group 3B, 5B, 6b elements. Inde-... 

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