Answer to Question #196761 in Inorganic Chemistry for Fana

Question

1. Write the Bragg equation and identify each symbol. X-ray from a palladium source ( λ = 0.576 Å) were reflected by a sample of copper at an angle 9.40°. This reflection corresponds to the unit cell length (d = a) with n = 2 in the Bragg equation. Calculate the length of the copper in cell.

2.Determine all the symmetry operations and elements (Cn, Sn, σ, E, i) for the following compounds:

i) PCl3Br2 molecule – trigonal bipyramid

ii) [PtClF2Br]2- molecule

iii) [RuBr2Cl2H2]2+ an octahedral complex

iv) Benzene derivative

v) [Co(NH3)4Cl2]+ molecule

3.b) Determine the point group of the following:

i) Test tube

. ii) C5H2CI3 molecule (planar)

iii) 5-Chloro-1,3-cyclopentadiene (planar)

iv) Mineral cube complex below

v) A dx2-y2 orbital

Answer 1

1.) Bragg's law provides the condition for a plane wave to be diffracted by a family of lattice planes: 2dsinθ=nλ. where d is the lattice spacing, θ the angle between the wavevector of the incident plane wave, k_o, and the lattice planes, λ its wave length and n is an integer, the order of the reflection.

2.) PCl3Br2 molecule – trigonal bipyramid

 [PtClF2Br]2- molecule

[RuBr2Cl2H2]2+ an octahedral complex

Benzene derivative

[Co(NH3)4Cl2]+ molecule

3.) Determine if the molecule is of high or low symmetry. If not, find the highest order rotation axis, C_n. Determine if the molecule has any C₂ axes perpendicular to the principal C_n axis. If so, then there are n such C₂ axes, and the molecule is in the D set of point groups.