Alkali metal-containing complexes with 2,2,6,6-tetramethyl-3,5-heptanedione (thd) and trifluoroacetylacetone (tfa) as ligands were studied by TG, DTA, DSC and MS methods. Of the complexes studied, Na(thd) and K(thd) sublimed completely, and NaPr(tfa)(4) and KPr(tfa)(4) sublimed almost completely in vacuum, but in an inert atmosphere the weight remaining was up to approximate to 20%. Surprisingly, KPr(tfa)(4) had higher volatility than the corresponding sodium complex. The strongest peaks in the mass spectra of the double complexes were due to NaPr(tfa)(3) and KPr(tfa)(3). The mass spectra of Na(thd) and K(thd) showed several different species. One thd ligand was always bonded to one or several alkali metal ions. The strongest peaks in both spectra were those due to M(3)thd(2) and M(2)thd.