There is the one 16-bit RAM available in the Intellivision and it is mapped into the Intellivision memory map from $0200-$035F.
$0200-$02EF: The Background table (BACKTAB)
$02F0-$02F0: EXEC Object GRAM Allocation Table Pointer
$02F1-$0318: 1610 Stack
$0319-$031C: 16 bit RAM for EXEC
$031D-$035C: Moving Object RAM data bases
$035D-$035F: 16-Bit RAM use by the Executive ROM