AFAIK compound verbs (複合動詞) are formed by prefixing 連用形 (ren'youkei, or stem form) of one verb to another "full" verb, e.g.:
- 巡り合う=巡る(めぐり)+ 合う
- 生み出す=生む(生み)+ 出す
And so on...
However, 引っ張る seems to not fit this pattern and feels like it was formed by combining 引く+張る, and not 引き+張る which would result in 引き張る.
Apparently there are compound verbs with 引き, e.g.:
- 引き出す
- 引き受ける
- 引き返す
- 引き止める
Even more interestingly, there is a verb that exists in both variations: 引き越す and 引っ越す, although I don't think I've ever seen the former outside of the dictionary.
So, is 引っ張る a compound verb? If not, is there a term for such verbs and are there others?