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Vapor growth of mercuric iodide tetragonal prismatic crystals

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Douglas McGregor / The effect of polyethylene addition on the growth of mercuric iodide (HgI[supscript]2) tetragonal
prismatic crystals is examined. Three types of polyethylene powder are utilized:
low molecular weight (¯Mw ~ 4 x 103), ultra high molecular weight (¯Mw ~ 3 x 6 106),
and spectrophotometric grade polyethylenes. Among these types of polyethylene, the low
molecular weight polyethylene produces the most significant change in HgI[supscript]2 morphology, with {110} being the most prominent crystal faces. Thermal desorption - gas chromatography/mass spectroscopy (TD-GC/MS) studies show that thermal desorption of the low
molecular weight polyethylene at 100°C and 150°C produce isomers of alkynes, odd nalkanes,
and methyl (even-n) alkyl ketones. HgI[supscript]2 growth runs with n-alkanes, with either neicosane, n-tetracosane, or n-hexatriacontane, cannot replicate the crystal shapes produced
during growth with the low molecular weight polyethylene, whereas HgI[supscript]2 growth runs
with ketones, with either 3-hexadecanone or 14-heptacosanone, produce HgI[supscript]2 tetragonal
prismatic crystals, similar to the crystals grown with the low molecular weight polyethylene.
C-O double bond contained in any ketone is a polar bond and this polar bond may
be attracted to the mercury atoms on the top-most layer of the {110} faces through dipoledipole
interaction. As a result, the growth of the {110} faces is impeded, with the crystals
elongated in the [001] direction and bounded by the {001} faces along with large, prismatic
{110} faces.

Identiferoai:union.ndltd.org:KSU/oai:krex.k-state.edu:2097/16693
Date January 1900
CreatorsAriesanti, Elsa
PublisherKansas State University
Source SetsK-State Research Exchange
Languageen_US
Detected LanguageEnglish
TypeDissertation

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