Selenium exists in several allotropes that interconvert aloft heating and cooling agitated out at altered temperatures and rates. As able in actinic reactions, selenium is usually an amorphous, brick-red powder.
The packing is a lot of close in the α form. In the Se8 rings, the Se-Se ambit is 233.5 message and Se-Se-Se bend is 105.7°. Added selenium allotropes may accommodate Se6 or Se7 rings.
The minimum ambit amid chains is 343.6 pm. Gray Se is formed by balmy heating of added allotropes, by apathetic cooling of aqueous Se, or by abbreviating Se breath just beneath the melting point.
more about: Selenium
from: Metal Powder
No comments:
Post a Comment