[AccessD] IIF syntaxis

hey group
What would be the correct syntasis on IIF part in the query below --

I'd like to for record NewDateOpened to equal value from the column [MS
Date Opened] if DEPT is in ("MSS","MID","SW","OW"), and to equal
[MID_Date_Opened] in other cases.

(IIF( [Ron Data mid].DEPT in ("MSS","MID","SW","OW") ,[Ron Data mid].[MS
Date Opened]) ELSE [MID_Date_Opened] AS NewDateOpened


SELECT TOP 5 [Ron Data mid].DEPT, [Ron Data mid].MID_Date_Opened, [Ron
Data mid].[MS Date Opened], MFRD.Disposition,  [Ron Data mid].ID
(IIF( [Ron Data mid].DEPT in ("MSS","MID","SW","OW") ,[Ron Data mid].[MS
Date Opened]) ELSE [MID_Date_Opened] AS NewDateOpened
FROM [Ron Data mid] INNER JOIN MFRD ON [Ron Data mid].ID = MFRD.ID;


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