The Y-axis shows the sine of the angle subtended at H; smaller values indicate a more linear X-H-centroid angle.

1. NUXWUA (dataDOI: /10.5517/CC10787R) 2.36Å

2. IHOHUJ (dataDOI: 10.5517/CCQCYLL) 2.21Å

With the intramolecular analysis, we have seen **IGELAJ** before as having the shortest approach. The X-H-centroid angle is also pretty linear. BONREB (dataDOI:10.1107/S0108270199009919) is almost as short at 2.17Å. Note that the distribution at almost linear angles is sparser for the intra- compared to the inter-molecular cases.

and an expansion:

A close CH…π approach is illustrated by WEGXIG (dataDOI: 10.5517/CCNDCBQ):

And here is CESZAD for a BH…π approach (dataDOI: 10.5517/CC101BP2 ).