Discussion Overview
The discussion revolves around the measurement and understanding of O-H bond lengths in water, particularly focusing on the differences between intramolecular and intermolecular bond lengths in various phases of water. Participants explore evidence from x-ray data and diffraction studies, questioning the commonly accepted bond lengths in liquid water.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- Some participants note that the O-H bond length in H2O is typically cited as 0.942 Å, but x-ray data suggests O···H peaks at 1.85 Å and 3.3 Å, indicating that shorter bond lengths may not be observed in liquid water.
- It is proposed that intramolecular H-O bond lengths are around 0.9 - 1.0 Å in liquid water at 25°C, while intermolecular hydrogen bond lengths are significantly longer, possibly around 1.8 Å.
- One participant questions why x-ray data does not show any O···H peaks under 1 Å, despite the common belief in shorter intramolecular bond lengths.
- Another participant mentions that radial distribution functions are often used to study the surrounding structure, and intramolecular bonds may be excluded from analysis since they do not provide additional insight.
Areas of Agreement / Disagreement
Participants express differing views on the validity of the commonly accepted bond lengths and the interpretation of x-ray data. There is no consensus on the reasons for the absence of shorter O···H peaks in the data.
Contextual Notes
The discussion highlights the complexity of measuring bond lengths in water and the influence of different phases and conditions on these measurements. There are unresolved questions regarding the interpretation of diffraction data and the significance of intramolecular versus intermolecular bonds.