Zintl line

Figure 4.6. Blocks of the Periodic Table. The names (symbols) of the so-called blocks are indicated. In the p block two types of elements can be considered, roughly separated by the Zintl line semi-metals in the left-hand part and non-metals in the right-hand part.

As can be inferred from their position in the Periodic Table, these elements pertain to the /7-block. The first of them (boron) is just above the Zintl line the others... 

The structure of MnP is a distorted variant of the NiAs type the metal atoms also have close contacts with each other in zigzag lines parallel to the a-b plane, which amounts to a total of four close metal atoms (Fig. 17.5). Simultaneously, the P atoms have moved up to a zigzag line this can be interpreted as a (P-) chain in the same manner as in Zintl phases. In NiP the distortion is different, allowing for the presence of P2 pairs (P ). These distortions are to be taken as Peierls distortions. Calculations of the electronic band structures can be summarized in short 9-10 valence electrons per metal atom favor the NiAs structure, 11-14 the MnP structure, and more than 14 the NiP structure (phosphorus contributes 5 valence electrons per metal atom) this is valid for phosphides. Arsenides and especially antimonides prefer the NiAs structure also for the larger electron counts. 

Fig. 5.7 Top Comparison of band structures for traditional and inversed E Xm Zintl phases, middk DOS plot for Sn24Pi9.3l8, solid line, with the contribution of the lone pairs of tin atoms, dashed line, bottom Population of the tin hybrid orbitals in Sn-M bonding as a function of the formal oxidation state of M...

Here ln(l) is two-coordinate while ln(2) and ln(3) are four-coordinate (there are two ln(2) and ln(3) sites for every single ln(l) atom). As the density of states plots show, this compound is metallic. A plot of the In populations is shown on the left side where the solid line, dashed line and dotted line refers to the ln(l), ln(2), and ln(3) atoms, respectively. The DOS plot on the right side shows the projected contributions to the X (solid line), y (dashed), and z (dotted) p AOs of the In atoms. How does this compound fit into the Zintl-Klemm counting scheme What do the crystal orbitals around the Fermi level look like ... 

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