Unable to Open Database: Remove Datafile

I receive the following error message when I try to open the database. I had just created the
database and added the following file to the tablespace had not yet backed it up.
There should not be any data stored in the file. Is there a workaround to this problem
(deleting the datafile etc.). There is another datafile in the ts which has data stored in it
and so it would not be possible for me to drop the tablespace. Thanks in anticipation
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SVRMGR> alter database open;
alter database open
*

ORA-01122: database file 31 failed verification check
ORA-01110: data file 31: 'G:\ORACLE\STS\SAPDATA6\BTABD_5\BTABD.DATA5'
ORA-01251: Unknown File Header Version read for file number 31