Previous perturbed angular correlation (PAC) spectroscopy measurements on the donor indium in CdTe and its alloys have revealed several defect complexes. One defect characterized by two sets of quadrupole interaction parameters, &ngr;Q=83 MHz, &eegr;=0.08 and &ngr;Q=92 MHz, &eegr;=0.08, was observed in Hg0.8Cd0.2Te (x=0.2 MCT) and attributed to the substitutional indium–metal vacancy complex InM2+3+VM2+. A defect characterized by &ngr;Q=61±1 MHz and asymmetry parameter &eegr; between 0 and 0.19 was seen in CdTe and widely attributed to the same complex. Both of these assignments were based mainly on an observed relationship between complex formation and the loss of metal ions. In this article we present PAC measurements on111In‐dopedx=0.45 MCT (Hg0.55Cd0.45Te). These measurements reveal defects having quadrupole interactions very similar to those seen previously in CdTe and inx=0.2 MCT. Two unique defect fractionsf1andf2, characterized by &ngr;Q1=60±3 MHz, &eegr;1≊0–0.2, and &ngr;Q2=87±4 MHz, &eegr;2≊0–0.15, were seen inx=0.45 MCT, in some cases simultaneously. The observation of both of these interactions in the same material—if they correspond to the defects seen in CdTe andx=0.21 MCT—precludes the possibility that they both correspond to precisely the same defect. We also observed a change in the relative fractions of these two defects with time at room temperature; the fractionf2vanished over a period of a day, whilef1andf0(the fraction of indium atoms in sites having cubic or higher symmetry) increased. While we cannot rule out the possibility of a slow electronic transition, at present we favor a model in which one of the interactions (probably the one near 60 MHz) corresponds to a complex in which indium is paired to a fast‐diffusing monovalent metal ion like Ag+, Cu+, or Li+. ©1995 American Institute of Physics.