求烷烃结构简式书写规则 并请举例写出戊烷己烷庚烷的几种同分异构体的结构简式 要最简
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书写规则.比如戊烷的话,先写5个c在一条直线,然后4个c一条直线,然后是三个c一条直线,多出来的c可以自己组合,再挂在刚写出来的碳链上,注意,相同的结构不能出现.

戊烷,分子式C5H12,其同分异构体有三种:

1.CH3-CH2-CH2-CH2-CH3 正戊烷

2.CH3-CH(CH3)-CH2-CH3 异戊烷(2-甲基丁烷)

3.C(CH3)4 新戊烷(2,2-二甲基丙烷)

己烷:

CH3-(CH2)4-CH3

CH3CH(CH3)-(CH2)3-CH3

CH3CH2CH(CH3)-(CH2)2-CH3

CH3CH(CH3)CH(CH3)CH2CH2CH3

CH3CH(CH3)CH2CH(CH3)CH2CH3

CH3CH(CH3)CH2CH2CH(CH3)CH3

CH3CH(CH3)CH(CH3)CH(CH3)CH3

庚烷:

CH3-(CH2)5-CH3

(CH3)2-CH-(CH2)3-CH3

CH3CH2CH(CH3)CH2CH2CH3

(CH3CH2)3CH

(CH3)3-C-CH2CH2CH3

(CH3CH2)2-C-(CH3)2

(CH3)2-CH-CH(CH3)-CH2CH3

(CH3)2-CH-CH2-CH-(CH3)2

(CH3)3-C-CH-(CH3)2