mobad [1] filed an orphan request for purple-hangouts-hg [2]: The repository doesn't exist any more https://bitbucket.org/EionRobb/purple-hangouts so the package isn't installable. It been moved to https://github.com/EionRobb/purple-hangouts but the maintainer hasn't responded in around a month.
[1] https://aur.archlinux.org/account/mobad/ [2] https://aur.archlinux.org/pkgbase/purple-hangouts-hg/
