Boranes, Carboranes, Zintl Ions and PSEPT

Flashcards covering Wade's Rules, PSEPT, and Zintl Ions

What are the characteristics of [B5H5]2- according to Wade's Rules?

5 vertices, p = 5, q = 0, c = 2, 5 x 2 = 10, 1 x 2 = 2, 6 pairs, p+1, and closo structure

How are clusters related in structure correlation?

Clusters with the same number of framework electron pairs are related by removing successive B-H groups (vertices) and adjusting electrons and hydrogen atoms.

What transformations link closo, nido, and arachno structures?

-BH -2e for closo, +4H for nido, and +2H for arachno, while maintaining 7 framework pairs.

What are the structural features of [B6H6]2-?

6 vertices, 7 framework pairs, and closo structure.

What are the structural features of B5H9?

5 vertices, 7 framework pairs, and nido structure.

What are the structural features of B4H10?

4 vertices, 7 framework pairs, and arachno structure.

How many electrons does each CH unit supply in carboranes?

Each CH unit supplies 3 electrons to the framework.

What is the general formula for carboranes?

[(CH)a(BH)pHq]c-

How do you calculate the total number of framework electrons in carboranes?

3a + 2p + q + c

How is the number of vertices determined in carboranes?

Total number of boron atoms and heteroatoms (a + p).

How many electrons do Group 15 and 16 elements contribute to hetero structures?

Group 15 contributes 3 electrons, and Group 16 contributes 4 electrons.

What are deltahedra?

Structures based on regular polyhedra with triangular faces.

According to PSEPT, how many electron pairs does a closo-deltahedral cluster core with n vertices require?

A closo-deltahedral cluster core with n vertices requires (n+1) pairs of electrons.

What electronic effect operates in Zintl ions?

The inert pair effect operates, and two electrons are available for cluster bonding.

Explain the electron counting and structure of [TlSn9]3-.

Tl supplies 1 electron, 9 Sn supply 18 electrons, and add the 3- charge, totaling 22 electrons and 11 pairs; closo structure.

What compounds should I know how to find the number of framework pairs and structure types?

Si2B10H12, SB9H11, B9H15, [B8H12] 2-, B6H12, [C2B5H7] 2-, [C2B4H10]2-