If you aren't sure if it's HR appropriate to talk to women at your workplace please check with your HR team.
I hope your HR team will encourage you to talk to women and ask what they like or dislike about their day-to-day. If they mention concerns or problems they’re having, I hope your HR team will encourage you to ask if there’s any way you could help make it better.
We are engineers answering from different countries. Different countries have different cultural norms and laws.
Don't go to HR with your problems, it can only hurt you. If you're the victim of something inappropriate in the workplace, seek outside legal advice and follow their direction in communicating with HR.
If you are thinking about it you should probably seek a lawyer because they are not your friend.
Nothing related to gender, but I once had a coworker at a mid-sized company angrily threaten me in his cubicle: "if we weren't in the office, I would slit your throat." I immediately went to HR about it and literally the first thing they asked me after I told them was "can anyone corroborate your story?" I couldn't since nobody overheard us, so I was screwed. It was the only time in my life that I actually feared for my life from another human being -- especially since I tried to report him. I walked to my car with a friend that night, fearing he'd be waiting for me in the parking lot.
This coworker had received complaints for other issues from others in my department as well, but the company just didn't act. He remained there until he finally was fired for incompetence.
In what workplace is it not appropriate to speak to someone else?
I'm not sure what you mean by this. What's the meaning of "HR appropriate"?