Room Temperature Synthesis and Crystal Structure of mer ‐[MoBr 3 Py 3 ], the Vibrational Spectra of mer ‐[MoBr 3 Py 3 ], mer ‐[MoI 3 Py 3 ] and trans , trans ‐[MoBr 2 Py 4 ][MoBr 4 Py 2 ]

The reaction of MoBr 3 and pyridine at room temperature provided single crystals of mer ‐[MoX 3 Py 3 ]. mer ‐[MoBr 3 Py 3 ] crystallizes in P 2 1 / n monoclinic space group with cell dimensions a = 9.2297(5) Å, b = 12.911(8) Å, c = 15.7022(9) Å and β = 90.479(3)°. There are four formula units in a unit cell. Mo–N distances are in the range 2.196(8)–2.214(8) Å and Mo–Br distances are 2.573(1) Å and 2.574(1) Å. Fundamental vibrational frequencies of pyridine molecules are strongly affected upon coordination in all three coordination compounds: mer ‐[MoBr 3 Py 3 ], mer ‐[MoI 3 Py 3 ] and trans , trans ‐[MoBr 2 Py 4 ][MoBr 4 Py 2 ].