Group compounds with metals

The elements show increasing metallic character down the group (Table 14.6). Carbon has definite nonmetallic properties it forms covalent compounds with nonmetals and ionic compounds with metals. The oxides of carbon and silicon are acidic. Germanium is a typical metalloid in that it exhibits metallic or nonmetallic properties according to the other element present in the compound. Tin and, even more so, lead have definite metallic properties. However, even though tin is classified as a metal, it is not far from the metalloids in the periodic table, and it does have some amphoteric properties. For example, tin reacts with both hot concentrated hydrochloric acid and hot alkali ... 

Am. In each ease, the answer is BuS. Part (ft) gives the ions and their charges, and so is perhaps easiest to answer. Part (know that periodic group IIA elements always form 2-t- ions in all their compounds and that sulfur forms a 2- ion in its compounds with metals. It is also necessary to remember that the metal is named first. In part (< ). the fact that there is only one compound of these two elements is deduced by the fact that the barium is stated with no Roman numeral, and that sulfide is a specific ion with a specific (2-) charge. 

Such a peculiarity has also been observed in many other compounds with metal-carbon bonds, especially cobalt-carbon. As part of a study (using the above-mentioned extended CNDO method) of the AM(CO)3 isoelectronic series (AM from 772-C2H4Ni to rj6-C6H6Cr) it was shown that, in the t 3-C3HsCo derivative, the allyl group was linked to cobalt by means of the two C(H2) carbons and not predominantly by the C(H) carbon atom, despite the fact that Co—C(H2) = 2.10 A as compared with Co—C(H) = 1.98 A (55). 

Similar to ethers and carbonyl compounds, sulfides or thiocarbonyl groups interact with metal carbene to generate the corresponding ylides. These ylides undergo similar subsequent reactions as their oxygen counterparts (Figure 4). 

According to Werner s co-ordination theory, compounds containing the radicles A, B, C, D, united with metal atom, should give optical isomers, the groups combined with metal taking up the positions,... 

An inner salt is a member of a special class of internal salts in which an acid group and a neutral group coordinate with metals to form a cyclic complex. These salts occur widely in analytical chemistry, (where they arc formed between metallic ions and organic reagents) in dyestuffs. 111 life processes (chlorophyll and hemadn belong to this class of compounds), and in many other fields. 

The elements show increasing metallic character down the group (Table 14.12). Carbon has definite nonmetallic properties it forms covalent compounds with nonmetals and ionic compounds with metals. The oxides of carbon and silicon are acidic. Germanium is a typical metalloid... 

The (simplified) theory of coloured compounds with metal ions from groups 3 up to and including 12 described above can be applied to solids and liquids. In this chapter, it serves to explain the colours of glazes and in chapter 11.2 Coarse Ceramics it explains the red colour of certain bricks. 

Figure 10-2. Although they are relatively rare in biology, organometallic compounds with metal-carbon bonds are important. An typical example is coenzyme B12. The cobalt is co-ordinated to a tetraazamacrocyclic ligand, and has one axial nitrogen donor heterocyclic ligand and one axial alkyl group. The figure illustrates only the core of the macrocycle and the axial groups.

The main synthetic technique for obtaining carbyne complexes is through the reaction of carbene compounds with metal halides, preferably with those of Group IIIA [259c] as, for example, through reaction (2.2) ... 

Organometallic compounds with metal-carbon bonds are formed by nearly all metallic elements, but those of transition metals show a diversity without parallel in main groups. Carbonyl has cyanide ligands are not considered organic, although they may also be present in organometallic compounds along with... 

The reaction of platinum dioxide with other metal dioxides can be separated into three groups—i.e., compounds with metal-oxygen coordination numbers of 4 2, 6 3, and 8 4. We have investigated only a single... 

Sulfur nitrides give a variety of complexes with NS groups by interaction of N4S4, S7NH, and similar compounds with metal carbonyls or halides, Where hydroxylic solvents are used, hydrogen abstraction occurs to give complexes with N—H bonds. Some examples of the varied types of compounds are the following ... 

The chemistry of Ru and Os compounds with metal-carbon bonds is extremely extensive and complicated. Much of this chemistry involves organic groups such as C5H5 and its substituted derivatives and arenes, effectively as spectator ligands, other groups being present as ligands. There is also an extensive chemistry of carbonyls like Ru3(CO)12 and other Ru and Os clusters. We can deal here only with some of the simpler compounds, especially those with M—C, M=C, MCp, and M(arene) bonds. 

The reduction of carbonyl compounds with metal hydride reagents can be viewed as nucleophilic addition of hydride to the carbonyl group. Addition of a hydride anion to an aldehyde or ketone produces an alkoxide anion, which on protonation gives the corresponding alcohol. Aldehydes give 1°-alcohols and ketone gives 2°-alcohols. 

Information about the binary main group metal hahdes abounds in numerous texts and tabulations. Table 2 gives a qualitative listing of many of the halide stoichiometries adopted by the main group metals. AU solid-state compounds tend to behave as salts with very low electrical conductivity. Many of the pure compounds with metals in their higher... 

The metal-NHs reductions of carbonyl groups are exceedingly fast reactions for the reaction of acetone with an ammoniated electron the rate is 9 x 10 M" s". Although many, particularly older, published experimental procedures for the metal-NHs reduction of ketones employ prolonged reaction times with excess metal, these conditions are unnecessarily harsh. The reactions of carbonyl compounds with metals in NH3 are effectively instantaneous and by using short reaction times it appears that reduction of terminal alkenes and disubstituted alkynes can be avoided.In addition to the functional groups mentioned above, alcohols, amines and ethers, other than epoxides, are usually stable to reductions of aldehydes and ketones by dissolving metals. " ... 

Several conventions are observed for inferring oxidation numbers, the use of which is particularly common in the names of compounds of transition elements. Hydrogen is considered positive (oxidation number I) in combination with non-metallic elements and negative (oxidation number —I) in combination with metallic elements. Organic groups combined with metal atoms are treated sometimes as anions (for example, a methyl ligand is usually considered to be a methanide ion, CH3 ), sometimes as neutral (e.g. carbon monooxide). Bonds between atoms of the same species make no contribution to oxidation number. 

Group VA — 3 in binary compounds with metals Mg3N2, Na3P, CsjAs +3, e.g., N02, PCI3... 

Group VIA (other than O) —2 in binary compounds with metals and H H2S, CaS, Fc2S3, Na2Se +4 with 0 and the lighter halogens, e.g., SO2, SeOj, Na2S03, SOf, ... 

Group VIIA — 1 in binary compounds with metals and H MgF2, KI, ZnCl2, FeBr3 Cl, Br, or I with O or with a hghter halogen... 

Addition of phenols to activated C—C multiple bonds is another method for O-aUcylation. Conjugated carbonyl compounds with -leaving groups react with metal phenoxides, giving the substituted products via addition-elimination, and the resulted /3-aryloxylated carbonyls are versatile intermediates for synthesis of heterocyclic compounds . Addition... 

The heavier elements in the same group (15) as nitrogen are occasionally known as pnictogens and their compounds with metals as pnictides . Although the elements form some compounds similar to those of nitrogen, there are very pronounced differences, as is found in other nonmetal groups (see Topics FI and F5). 

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