.在下列有关晶体的叙述中正确的是:      A.晶体中有阳离子就

.在下列有关晶体的叙述中正确的是:     

A.晶体中有阳离子就一定存在阴离子   

B.原子晶体中,一定只存在共价键

C.金属晶体的熔点一定比分子晶体高       

D.分子晶体中一定存在共价键和分子间作用力

 

答案

B

解析:略

 

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