I. The Investigation of the Alloy System Lead-Thallium. II. The Investigation of the Crystal Structure of the Complex of Hexamethylenetetramine with Manganous Chloride

Author: Tang, You-Chi

Year: 1950

Degree: Dissertation (Ph.D.)

Advisors: Pauling, Linus; Sturdivant, James Holmes

Committee Member: Unknown, Unknown

Option: Chemistry; Physics

DOI: 10.7907/NVF2-SD16

Abstract

Part I: The Investigation of the Alloy System Lead-Thallium. The lattice spacings for alloys in the lead phase of the system lead-thallium were accurately determined. The lattice-spacing-composition curve disagrees with that previously constructed by Olander on the basis of his fewer determinations. The new curve indicated that ordered phases PbTl_3 and PbTlTl_6 probably occur.

Part II: The Investigation of the Crystal Structure of the Complex of Hexamethylenetetramine with Manganous Chloride. Suitable crystals of the complex of hexamethylenetetramine with manganous chloride were grown in a 1:1 mixture of alcohol and acetone. By chemical analysis the composition was shown to correspond to the formula, 2(CH_2)6N_4•MnCl_2•2H_20. The crystal has a pseudo unit cell with a_1 = 11.80 Å., a_2 = 22.00 Å., a_3 = 7.21 Å., and Z = 4. The pseudo space group is C^9_(2v)-P2_1nb. A few weak reflections indicate that the a_1 axis should be doubled, but no account was taken of this in the present determination.

A trial structure derived from steric considerations and the

intensities of reflections h00 led to a satisfactory interpretation of the Patterson distribution function. The approximate structure based on the Patterson syntheses was confirmed by the Fourier projections ρ(x) and ρ(y,x), and by calculation of structure factors for reflections h00 and Okℓ.

The structure has the following important features. A manganese

atom lies on the common three-fold axis of two hexamethylenetetramine molecules at the center of symmetry of a complex molecule, and the Mn-Cl bonds are approximately perpendicular to the Mn-N bonds. Both the Patterson syntheses andthe Fourier projections indicate that two molecules of water are present in each complex molecule, and the Mn-O bonds are approximately normal to the plane of the Mn-Cl and Mn-N bonds.

Files