1. What is the formula for vanadium (I) oxide?
2. What is the name of Rb2O?
Why are you coming here and waiting on an answer when you can type in yourself and get the answer immediately?
Type in to Google these two and you'll get immediate results.
Second question is how much effort did you spend in trying to find the answers to you other questions? We're here to help and we're happy to do that but we're here to HELP not to GIVE you all the answers.