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We present the first Herschel spectroscopic detections of the [O i] 63 μm and [C ii] 158 μm fine-structure transitions, and a single para-H 2 O line from the 35× 15 kpc 2 shocked intergalactic filament in Stephan's Quintet. The filament is believed to have been formed when a high-speed intruder to the group collided with a clumpy intergroup gas. Observations with the PACS spectrometer provide evidence for broad (> 1000 km s− 1) luminous [C ii] line profiles, as well as fainter [O i] 63 μm emission. SPIRE FTS observations reveal water emission from the pH 2 O (1 11–0 00) transition at several positions in the filament, but no other molecular lines. The H 2 O line is narrow and may be associated with denser intermediate-velocity gas experiencing the strongest shock-heating. The [C ii]/PAH tot and [C ii]/FIR ratios are too large to be explained by normal photo-electric heating in photodissociation regions. H ii region …