✔ 最佳答案
圖片參考：
http://i320.photobucket.com/albums/nn347/old-master/20130104_1_zps2fef7384.png
http://i320.photobucket.com/albums/nn347/old-master/20130104_1_zps2fef7384.png
2013-01-05 23:44:53 補充：
Why Si and O can't form double bond while P and S can do so with O?
The size of Si atom is greater than those of P and S, and thus the side overlapping of p orbitals for Si atom and O atom is less effective, and the π bond formed betwen Si and O atoms is weaker.
2013-01-05 23:49:15 補充：
However, it was found that O=Si=O molecules are formed when SiO2 solid is decomposed at a high temperature.
2013-01-05 23:50:32 補充：
both Si,P and S are using their 3p orbital and hence weak interaction with 2p of O, and can't form pi bond right?
The weak π bond is due to the low effectively of side overlapping, but not due to what type of orbital is used.
2013-01-05 23:51:34 補充：
The weak π bond is due to the side overlapping of orbitals is not effective, but is not due to what type of orbital is used.
2013-01-14 22:46:19 補充：
In comparing with P=O and S=O bonds, Si=O bond is weaker may be due to the fact that Si has greater size and weaker nuclear charge than P and S.
