Studies of indium amides and nitrides

A reaction between InI{sub 3} and 3 eq. of KNH{sub 2} in liquid NH{sub 3} forms indium(III) amide (In(NH{sub 2}){sub 3}) a white, nearly insoluble compound. Indium(III) amide readily combines with KNH{sub 2} in liquid NH{sub 3} to form the mixed metal amide K{sub 2}In(NH{sub 2}){sub 5}. Other potassium and sodium derivatives MxIn(NH{sub 2}){sub 3+x} derivatives were prepared in a similar manner, but not all were obtained pure in the solid state. An impure tri-lithium derivative (Li{sub 3}In(NH{sub 2}){sub 6}) was obtained by adding a KNH{sub 2} solution (6 eq) to a solution of InI{sub 3} and 3 eq of LiI. Pyrolysis (in vacuo 25-300{degrees}C, under N{sub 2} 300-400{degrees}C) of In(NH{sub 2}){sub 3} or MxIn(NH{sub 2}){sub x+3} (M = Na, K) to 400{degrees}C results in the formation of InN, but indium metal is also formed from some of the mixed metal amides. The product from thermal decomposition of Li{sub 3}In(NH{sub 2}){sub 6} under vacuum was tentatively identified as the ternary nitride Li{sub 3}InN{sub 2}. Products were characterized by elemental analysis, IR spectroscopy, and powder x-ray diffraction experiments.