Matter, such as water, can be in three states: solid, ice; liquid, water; and gas, water vapor. Most of matter changes state in this or the reverse order. It does not skip from solid to gas without going through the central stage. There are, however; some exceptions: CO2 and Pt for example. The solid state of CO2 is dry ice. Dry ice skips the central state and goes directly to the gaseous state. We sometimes receive shipments of food containing dry ice to keep it cold. You can see it going to vapor directly by the vapor effervescing from it. My kids used to say it smokes.
Ice, frozen water, melts to its liquid state; water. If you heat water it will eventually get to its boiling point 212° F. At that point, steam rises from it and into the air. The steam is water vapor.
Platinum, like CO2 goes directly from its solid state to its gaseous state. This characteristic can be used as part of the sublimation process to purify it from its impurities. During the sublimation process of platinum, is vaporized with heat. It then solidifies on the cool "cold finger" back to a solid, having been purified in the process.
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| Sublimation Process |
Thanks to Lisa Nichols' article on, Sublimation we have the diagram above. The nipple on the side of the outer tube is attached to a vacuum pump which lowers the air pressure in the space between the inner and outer test tubes. This pressure drop expedites the process. The sublimed platinum is drawn and attached to the cooler "room temperature cold finger" tube.
I've said all this hoping to make what is to a difficult concept to me clear to you whom I assume can understand.
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| Sublimed Platinum |
I think the ridges and valleys are provided to aid in locating the attachment of the sublimed platinum. This must be the outer surface of the "cold finger tube" in the industrial process of sublimation. The sample does not provide the location source of the platinum.
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| Sublimed Platinum |
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