Cluster chemistry. Study of the pyrolysis of Ru3(.mu.-dppf)(CO)10 (dppf = 1,1'-bis(diphenylphosphino)ferrocene). X-ray structures of Ru3(.mu.-H){.mu.3-(.eta.1,.eta.2-C6H4)PPh(.eta.-C5H4)Fe(.eta.-C5H4PPh1)}(CO)8, Ru3{(.mu.-P(C6H4)-.eta.-C5H4)Fe(.eta.-C5H4PPh2)}{.mu.-CO)(CO)8, Ru3(.mu.3-.eta.1,.eta.1.eta.2-C6H4)(.mu.-PPh2)(.mu.-PPh2)(.mu.-PPhFc)(CO)7, Ru3(.mu.-H){.mu.3-(.eta.1,.eta.5-PPh2C5H3)Fe(.eta.-C5H4PPh2)}(CO)7, and Ru4(.mu.4-PFc)(.mu.-C6H4)(.mu.-CO)(CO)10 (Fc = Fe(.eta.-C5H5)(.eta.-C5H4))