Communism is State Socialism. It should be wrong to say that it is the only socialism out there, but it is definitely socialism.
Soviet communism was (corrupted) state capitalism disguised as state socialism.
Russia was truly communist for a few years after the Russian revolution, until the Bolsheviks took over and turned everything on its head and forever corrupted the word "communism". Now, instead of thinking "oh, communal ownership of the means of production so all may be equal", most people think "oh, corrupted state owns everything and represses its people so that a select few can have it unimaginably better than others" - which is so far from (any of) the communistic ideals that it's almost impossible to go any further.
Soviet communism was communistic in name only.