A viral Facebook video’s caption claims “H20 is not healthy” and that “we’re really supposed to be consuming H302”.

Another post states structured water is “10x more Hydrating, Alkaline, and Nutrient Then H20”.

Several posts claim fruit is the best source of H302. Other users spruik machines and devices to supposedly turn regular water into H302, such as by creating a vortex, or using a terahertz radiation device.

But Professor Timothy Schmidt, head of the School of Chemistry at the University of New South Wales, explained that structured water is a “fiction”. 

“The proposed material known as ‘structured water’ does not exist,” he told AAP FactCheck. 

“There is only one type of pure water, and its structure is dynamic.” 

In an article for The Conversation, he says the supposed chemical formula, H302, is evidence that structured water is a fantasy.

“If water somehow changed into a H3O2 form, simple arithmetic shows that turning two molecules of H2O into one of H3O2 would leave an extra hydrogen atom floating around,” Prof Schmidt wrote.

“We would expect to see this hydrogen released as H2 gas. Alternatively, the reaction would need to bring in extra oxygen from the air. A simple experiment would show that neither of these happen.”

He concluded that “structured water” cannot be anything but H20.

Dr Dan Preston, from the Australian National University’s College of Science, agrees.

“Companies making claims about the existence of H3O2 to sell their products are careful to never give its actual molecular structure and say how the molecule would look, and with good reason, as the molecule wouldn’t make chemical sense (and, also, wouldn’t be water!)” Dr Preston told AAP FactCheck.

If it did exist, he said it would resemble hydrogen peroxide (H2O2), which he described as highly reactive and harmful to humans.

“We are very lucky that our bodies aren’t full of this imaginary molecule: it would lead to our rapid and painful death. Even if it did exist, I wouldn’t advise drinking it.” 

Dr Haihui Joy Jiang, a lecturer in the School of Chemistry at the University of Sydney, said suggestions that water could be hexagonal in structure are false. 

She said that water, as a liquid, is “highly dynamic” and without a well-defined structure.

Dr Preston agrees, adding that the claim simply doesn't make sense.

“The interactions between individual water molecules are weak and are constantly breaking and reforming as the water molecules jiggle and bounce about, with all of this happening on under or around the picosecond scale,” he said. 

“The interactions simply aren’t strong or long lived enough to allow the liquid to have any long range structure.”

All three experts rubbished the idea that devices could be used to alter the structure and chemical makeup of water.

Using terahertz radiation devices, as some users suggest, would make no lasting changes to the structure of water, but perhaps heat it slightly, Prof Schmidt said. 

Dr Preston also said it was nonsense to suggest fruit is a good source of H302.

He noted there are many benefits to eating fruit and vegetables, including their nutrients and high water content.

“But the actual water, the H2O molecules themselves, has the same molecular construction and long range structure regardless of where you get it from, whether that is from fruit, vegetables, or a puddle of rainwater, ” he said.

“Water is water is water.”