Appeal No. 1998-1405
Application No. 08/379,600
Both the examiner and appellants agree that Henderson
teaches reacting a metal oxide with a gas mixture containing
carbon disulfide and hydrogen sulfide at the claimed
temperature to form the corresponding metal sulfide. See
Answer, page 4, and Brief, pages 7 and 8. The examiner and
appellants agree that Johnson teaches reacting hydrogen
sulfide with electrically conductive carbon particles, such as
petroleum coke, to produce a mixture containing, inter alia,
carbon disulfide and hydrogen sulfide. See Answer, page 7,
and Brief, page 7. The dispositive question is therefore
whether it would have been obvious to pass the carbon
disulfide and hydrogen sulfide gases produced in situ in the
process of Johnson directly (without any intervening steps) to
the process of Henderson. We answer this question in the
negative.
As is recognized by appellants (Brief, pages 7 and 8),
Henderson is directed to forming high purity single crystal
metal sulfides, which are useful as semiconductors,
transistors, etc. See also Henderson, abstract and column 2,
lines 19-27. To form the high purity metal sulfides,
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