SQL Server - contains an invalid XML identifier as required by FOR XML;

I'm ruing this query and getting below mentioned error. Can anyone help?

Column name 'Middle' contains an invalid XML identifier as required by FOR XML; ' '(0x0020) is the first character at fault.

SELECT 
    Useame as [LastName],
    '' AS [Middle],
    '' AS Birthdate,
    '' AS [SSN],
    0 AS [Wage Amount]
    FROM
    Employee
     FOR XML PATH