Why does H2O2 have a gauche structure? The gauche structure of $\ce{H_2O2}$ is quite well known. It has the two $\ce{OH}$ groups in different planes at right angles. Why does it adopt this structure? 

I can understand that it might have something to do with the repulsions between the lone pairs on the oxygens. But in that case a staggered structure would make more sense since that minimises the repulsion even further. Maybe another factor is at play here that I am missing. 

EDIT: My main question in this post is why the gauche structure arises in the first place. However, the other post is mainly focussed on the variation of the dihedral angle in different phases. Although the OP asks why hydrogen peroxide adopts a gauche structure, a satisfactory answer has not been provided. (Note that the OP has accepted the provided answer. Since that does not answer my main question, I think a new question is justified in this regard)
In liquid or gas and even in solid hydrogen peroxide has a gauche structure. One reason for this is to reduce electronic repulsion and the other is to give a well packed structure in solid phase.also the interactions between different molecules leads to a gauche structure in liquid and gas.