Alkali metals Group structures

The niobium-arseitic compounds described here, with novel anionic structures, clearly demonstrate the many possibilities for stractural motifs in this system. Similarly high potential for diverse structures and properties should be expected for the heavier pitictides when combined with other transition metals and the alkali-metal group. 

Bare group 13 metal vertices (e.g., Ga, In, Tl) provide, as noted above, only one skeletal electron each to polyhedral cluster structures. Thus it is not surprising that the bare metal cluster ions Enz (E = group 13 element) found in homonuclear alkali-metal/group 13 intermetallic phases [86-89] (mainly for In and Tl) have charges less negative than the — (n + 2) (i.e., z [Pg.21]

In Table 6.2 we saw that the total number of orbitals in each shell equals r 1,4,9, or 16. Because we can place two electrons in each orbital, each shell accommodates up to 2rf electrons 2,8,18, or 32. We see that the overall structure of the periodic table reflects these electron numbers Each row of the table has 2, 8, 18, or 32 elements in it. As shown in T Figure 6.30, the periodic table can be further divided into four blocks based on the filling order of orbitals. On the left are two blue columns of elements. These elements, known as the alkali metals (group lA) and alkaline earth metals (group 2A), are those in which the valence s orbitals are being filled. These two columns make up the 5 block of the periodic table. 

The alkali metals, group I of the periodic table, are Li, Na, K, Rb, Cs, and Fr. Their atomic numbers are 3, 11, 19,37,55, and 87, respectively. How do they differ in electronic structure from the argonons that precede them in the periodic table ... 

The predominantly ionic alkali metal sulfides M2S (Li, Na, K, Rb, Cs) adopt the antifluorite structure (p. 118) in which each S atom is surrounded by a cube of 8 M and each M by a tetrahedron of S. The alkaline earth sulfides MS (Mg, Ca, Sr, Ba) adopt the NaCl-type 6 6 structure (p. 242) as do many other monosulfides of rather less basic metals (M = Pb, Mn, La, Ce, Pr, Nd, Sm, Eu, Tb, Ho, Th, U, Pu). However, many metals in the later transition element groups show substantial trends to increasing covalency leading either to lower coordination numbers or to layer-lattice structures. Thus MS (Be, Zn, Cd, Hg) adopt the 4 4 zinc blende structure (p. 1210) and ZnS, CdS and MnS also crystallize in the 4 4 wurtzite modification (p. 1210). In both of these structures both M and S are tetrahedrally coordinated, whereas PtS, which also has 4 4... 

In mimicking this type of function, noncyclic artificial carboxylic ionophores having two terminal groups of hydroxyl and carboxylic acid moieties were synthesized and the selective transport of alkali metal cations were examined by Yamazaki et al. 9 10). Noncyclic polyethers take on a pseudo-cyclic structure when coordinating cations and so it is possible to achieve the desired selectivity for specific cations by adjusting the length of the polyether chain 2). However, they were not able to observe any relationship between the selectivity and the structure of the host molecules in an active transport system using ionophores 1-3 10). (Table 1)... 

The yielded product can be converted to a surface-active compound if at least one ester group has been transformed to the free acid or an alkali metal salt thereof [160]. There are also many compounds from phosphinic acid derivatives claimed to be useful as sequestrants and builders to improve detergency, especially bisphosphonylmethylphosphinic acids and polyphosphinic acids [structures (9) and (10)], respectively ... 

Electronic Effects in Metallocenes and Certain Related Systems, 10, 79 Electronic Structure of Alkali Metal Adducts of Aromatic Hydrocarbons, 2, 115 Fast Exchange Reactions of Group I, II, and III Organometallic Compounds, 8,167 Fluorocarbon Derivatives of Metals, 1, 143 Heterocyclic Organoboranes, 2, 257... 

---