Nuclear quadrupole resonance spectra of 5-7 group heavy transition metal chlorides and oxochlorides

Studied are the NQR spectra and the structure of chlorides and oxochlorides of formally penta- and hexavalent heavy transition metals of the 5-7 groups of the Periodical system with the following compositions: WCl6, MoCl4 (M=Mo,W,Re), Mo2Cl2 (M=Mo, W), MCl5 (M=Nb,Ta,Mo,W,Re), MoCl3 (M=Nb,Mo,W). Is is shown that all pentachlorides, except of TaCl5, posess several polymorphic forms, all having a modification with the TaCl5 structure. The WCl6 low-temperature phase has a structure of its own type, the high-temperature one - the one of the UCl6. Proposed is the model of the MoOCl4 structure of the dimer type. The interrelation of structures of the investigated compounds is considered