Someone told me that by changing that angle, the properties of the water also change. I don’t know if I can believe this. An additional question is therefore also: how is the angle between those H and H and O determined? Is it unequivocally demonstrable that that angle is 104 or eg 109 degrees?
Answer
Hi Gabi,
The angle HOH in water is indeed about 104° (see the picture; oxygen is represented in red and hydrogen in light blue).
This angle can indeed be varied. When water is irradiated with light with a wavelength of about 7500 nm, that angle will vary. That change is not permanent, however: the angle will oscillate, increasing and decreasing alternately, similar to a curved spring being compressed, then released.
However, this does not change the properties of water at all. After all, this light belongs to the range of infrared radiation or heat radiation. So this phenomenon happens every time you heat water.
Answered by
Dr Etienne Jooken
Chemistry
Old Market 13 3000 Leuven
https://www.kuleuven.be/
.