The mongo C driver allows users to create collections containing periods but cannot rename a collection to include a period. For example, a collection named "a.b" can be created but cannot be renamed to "a.b.c". Similar implementations in the Java driver and the command-line tools allow for such changes.

A work around is available by using mongoc_client_command/_simple to run the following against the 'admin' database:

{ renameCollection:"database_name.a.b", to: "database_name.a.b.c", }