Assertion: gray tin | /r/HasProperty | low temperature form
Facets:
Source sentences:
text: Tin has two forms (allotropes) one is "white tin" (beta-tin) which is a metal although some chemists/metrial scientists would call it a "poor metal"- and "grey tin" (alpha-tin), a low temperature form, which has a similar structure to diamond and more covalent in character.