INTRO: localized bonding theories simplistic, but still useful delocalized bonding theories more sophisticated and more accurate Certain problems can be more than adequately described by localized approach, and yet the others require Molecular Orb
SEMICONDUCTORS and QUANTUM DOTS When exposed to external stimulus (voltage, photon flux, etc) semiconductors conduct electricity if that stimulus is large enough to bridge the band gap. This allows manipulation and regulation of the electrical current. Fo
METALS IN ELECTRONICS
Metal materials are indispensable in electronics industry due to their electricity conducting properties, but also malleability.
Starting from Cu which is the basic element of the printed circuit boards (PCB). PCB's
The chemistry of life involves 25 different elements: "organic": C, H, N, O, P macronutrients: Na, K, Mg, Ca, S, Cl, Si, Fe micronutrients: V, Cr, Mn, Co, Ni, Zn, Mo, W, Se, F, and I The metallic elements can play various roles with
Crucial feature: M-C bond (with exception of CO); compounds such as (C3H7O)4Ti do not count (Ti-O bond), but C6H5Ti(C3H7O)3 does (phenyl group bound through C).
Under organometallic class organic compounds of B, P, and Si are al
WHAT DETERMINES THE EXTENT OF CRYSTAL FIELD SPLITTING?
1. THE NATURE OF THE LIGAND its Lewis basicity; although that may be oversimplified. Existence of * orbitals on the ligand can also be important. Assuming we have the same metal ion different ligands
MOLECULAR ORBITAL APPROACH
Crystal field theory treats ligands as point charges and it is functional in explaining the splitting in d orbitals, but it does not take into account the orbital overlap and does not give a realistic picture how the bonds are
METALS (e- deficient species) are surrounded by LIGANDS (e- donors). The main feature is formation of COORDINATE COVALENT (dative) bond.
Ligands can bind to the metal atom via the C atom of organic compound (ORGANOMETALLIC chemistry
STRICT DEFINITION: those elements that have partly filled d or f shells
BROADER DEFINITION: also includes elements that have partly filled d and f shells IN COMPOUNDS; so under this definition, the coinage metals, Cu, Ag, and Au would
GROUP VIB (16) ELEMENTS
ns2np4: O, S, Se, Te, Po
Oxygen compounds of all elements except He, Ne, and Ar known. Molecular O2 reacts, at room temperature or on heating, with all other elements except the halogens, noble metals, and noble gases.
MAIN GROUP ELEMENTS PART II
GROUP IVB (14) ELEMENTS C, Si, Ge, Sn, Pb ns2np4
All are extremely important from technological point of view. C forms a basis for life chemistry. Pb also has environmental impact, due to its widespread use and high toxicity!
THE MAIN GROUP ELEMENTS
HYDROGEN: 1s1, forms more compounds than any other element.
The chemistry of H depends on 3 processes: 1. Loss of the only valence eH+ (proton)
H+ is small (1.5 x 10-15m, compared to atom sizes 10-10m or 1 ) and highl
MELTING AND BOILING POINTS
FUSION (MELTING) and VAPORIZATION (CONDENSATION) are result of providing a crystal or molecular solid with sufficient thermal energy to allow it to overcome the potential energy that holds it together. in most cases melting and
THE SOLID STATE: METALLIC BONDING, CONDUCTORS, SEMICONDUCTORS, INSULATORS
Inorganic solids have many mechanical useful properties, but their electrical, magnetic, and optical properties are far more interesting from technological point of view. METALLIC B
ionic solids can best be described as consisting of 3-dimensional efficiently packed arrays of ions the energy of this array of ions can be treated as the sum of following contributions: 1. Coulombic (electrostatic) attractive and repulsive
TRIGONAL PLANAR MOLECULES: AB3 bonding in planar systems CO32-, NO3 central atom in the origin of the coordinate system molecular plane coincident with xy plane bonding system formed entirely from pz orbitals of the 4 atoms the node is in the xy plane sys
MOLECULAR ORBITAL (MO) THEORY
a chemical bond exists when valence orbitals on different atoms overlap, e- density is concentrated between atomic cores if 2 atoms approach each other closely enough to have reasonable amplitudes in a region between them OR
The MO Diagram for Water
Introduction In this lecture we will go though forming the MO diagram for a simple molecule together. Tomorrow we will come back and I will explain many of the steps in more detail Point group C2v the first steps in forming a MO d