Chemistry of Isomorphous and Doped Semiconductors

Isomorphous Substances

• Isomorphous substances have the same crystal structure but different chemical compositions.

Polymorphic Forms of Sulphur

• Sulphur exists in various allotropic forms, often referred to as polymorphic forms.

Boron-doped Silicon Semiconductor

• Boron added as an impurity to silicon creates a p-type semiconductor.

Phosphorus-doped Silicon Semiconductor

• Doping silicon with phosphorus results in an n-type semiconductor.

Coordination Number of Na+ in NaCl

• Given the ionic radii of Na+ (0.95 Å) and Cl- (1.81 Å), the coordination number of Na+ in NaCl is 6.

Ionic Crystal Structure Prediction

• With cation radius of 0.95 Å and anion radius of 1.81 Å, the ionic crystal structure is likely NaCl structure.

Magnetic Property of Cl- Ion

• Chlorine (Z=17) has 17 electrons and all its orbitals are paired, making the Cl- ion diamagnetic.

Magnetic Property of Ni Atom

• Nickel (Z=28) atom is paramagnetic due to unpaired electrons.

Method for Determining Magnetic Properties

• Magnetic susceptibility measurements are used to determine the magnetic properties of substances.

Formula of a Compound with FCC Structure

• If atom C is at the corners and atom D at the faces of an FCC structure, the formula of the compound is CD.

Type of Solid in S8

• S8 (sulfur) molecule forms a molecular solid.

Type of Solid in Ammonium Phosphate

• Ammonium phosphate forms an ionic solid.

Uses of Fullerene

• Fullerenes have various applications, including lubricants, catalysts, and semiconductors.

Hybridization in Fullerene

• Carbon atoms in fullerenes exhibit sp2 hybridization.

Interlayer Force in Graphite

• The layers of carbon atoms in graphite are held together by weak van der Waals forces.

Schottky Defect Density Variation

• Schottky defects decrease the density of the solid.

Frenkel Defect Density Variation

• Frenkel defects have a negligible effect on the density of the solid.

Carbon Mass in Fullerene Sample

• 0.1 mole of Buckminster Fullerene contains 12 grams of Carbon.

Unit Cells in BCC Compound

• 58.5 grams of a BCC compound contains 0.1 mole of the compound and 1/2 x NA unit cells.

Lattice Point Occupation Example

• Elemental solids, such as copper (Cu), are examples where the atoms occupy lattice points.

Explore the fascinating world of isomorphous substances, polymorphic forms of sulphur, and the doping processes in silicon semiconductors. This quiz covers key concepts such as ionic crystal structures and magnetic properties of various ions and elements. Test your understanding of these important chemistry topics.