K2Eu(PO4)(WO4) has been prepared via the high-temperature solution growth (HTSG) method using K2WO4–KPO3 molten salts as a self-flux and characterized by single-crystal X-ray diffraction analysis, IR and luminescence spectroscopy.

A synthesis procedure was developed and a new carbacylamidophosphate type ligand N,N'-tetraethyl-N''-trifluoroacetylphosphoroustriamide (CF3C(O)NHP(O)(NC2H5)2, HL) that contains C(O)NP(O) chelating fragment was isolated in the crystalline state. A mononuclear erbium complex [Er(HL)3(NO3)3] and a tetranuclear nickel complex [Ni4L4(OCH3)4(CH3OH)4] were isolated in the crystalline state. The suggestion about the type and coordination mode of the ligand in complexes was made based on IR spectroscopic investigations: deprotonated (acido-) form in bidentate manner in nickel complex and neutral form in monodentate manner in erbium complex. According to X-ray structural studies, different coordination modes of the ligand in complexes were determined: bidentate chelate manner via the oxygen atoms of the phosphoryl and carbonyl groups of the ligand with the formation of six-membered chelate cycles in case of nickel complex and monodentate manner via the oxygen atom of the phosphoryl group of the ligand in case of erbium complex, the coordination polyhedron of which was interpreted as a distorted three-handed trigonal prism.