Restriction on the CHARACTER SET

Do not specify the AL16UTF16 character set as the database character set.

Specify the national character set used to store data in columns specifically defined as NCHAR, NCLOB, or NVARCHAR2. Values allowed are AL16UTF16 and UTF8. The default value is AL16UTF16.

Also, refer to the Oracle Database Globalization Support Guide for information on Unicode data-type support. You can access this document at

http://download.oracle.com/docs/cd/B12037_01/server.101/b10749/toc.htm