Optical measurements have shown that the two types of Y(HCOO)3, i.e. the powder type and the recrystallized type, have notable differences in second harmonic properties as measured with a Nd:YAG laser. We performed a neutron time-of-flight measurement on the powder type in order to explain the optical behaviour by structural differences.
The results show that the position parameters of the heavy atoms of the powder type are the same as those given by a single crystal X-ray study for the recrystallized type. Moreover the position parameters of the hydrogen atoms were determined for the first time. The effect of contamination determined by neutron activation analysis is also shortly discussed.