頭版
Appearance
維基同享 |
是日靚相
Interrupted Reading by French artist Jean-Baptiste-Camille Corot. Today is World Book Day.
是日影音
![]() Preparation of amorphous silicon (1) and magnesium silicide (2), upon reduction of powdered sand with magnesium powder:
(1) SiO2(s) + 2Mg(s) = Si(s) + 2MgO(s); and (2) 2Mg(s) + Si(s) = Mg2Si(s).The reaction described by (1) is initiated by heating; then it is self-sustained and is highly exoenergetic. |
每月攝影挑戰賽
Highlights
內容
主題 |