Residual gases in Hgl2 crystal growth ampoules

Vapor Growth of Mercuric Iodide Tetragonal Prismatic Crystals

“…The effects of the stoichiometry and purity of the starting HgI 2 were deemed inconsequential, unlike claimed previously in [29,30] Gases -Therefore, the organic materials seemed to behave as inert gases, prompting futher studies in HgI 2 mass transport in horizontal furnaces [48][49][50][51], as well as HgI 2 with inert gases [52,53] Faile -Purification of the starting HgI 2 was not done because the author believed that HgI 2 purification was not needed to produce platelet crystals. Although the formation of HgI 2 platelet was not known, and was not attempted to be proven, the author assumed that polymer transport, formation, and/or disassociation might be the factors that influenced the platelet formation.…”

“…The analysis of the results implies that instead of having the characteristics of a chemical vapor transport, as claimed in [29], the analyzed vapor transport has the characteristics of a physical vapor transport, with sublimation and condensation of HgI 2 being the principal crystallization processes [32]. Therefore, the organic materials seemed to behave as inert gases, prompting futher studies in HgI 2 mass transport in horizontal furnaces [48][49][50][51], as well as HgI 2 with inert gases [52,53] The presence of residual gases mentioned above and the total pressure inside the ampoule are partially responsible for the shapes of the crystals. The existence of convective flow (causing non-stable growth forms) was implied by the occurrence of needleand dendrite-shaped crystals, while a more stable growth would produce crystallites and platelets.…”

“…Explanations on the effect of polyethylene addition to HgI 2 crystallization, posed by previous studies [28][29][30][47][48][49][50][51][52], have been proven inadequate. Even though the use of non-purified HgI 2 was suggested [28,47], the contents of the growth ampoule cannot be ascertained accurately.…”

Developments in Measuring and Calculating Chemical Vapor Transport Phenomena Demonstrated on Cr, Mo, W, and Their Compounds

“…In typical transport experiments (horizontal position of the transport ampule with respect to the gravitation vector) at higher total pressures convection increases the transport rate. Such effects on the transport rates were investigated in the transport systems GaAs/HCl, Ge/I 2 , ,− Ge/GeI 4 , Ge/GeCl 4 , GeSe/GeI 4 , GeTe/GeI 4 , SnS 2 /I 2 , SnS 2 /SnI 4 , Sb/GaCl 3 , Ni/CO, − MnS/MnSe/I 2 , ZnS/I 2 , ,, ZnSiP 2 /I 2 , YbAs/I 2 , TaS 2 /S 2 150 and Hg 1 - x Cd x Te/HgI 2 . ,, A general treatment of this problem was given by Schäfer et al , Reed et al, and Curtis and Dismukes …”