Unfortunately, there is no chemical compound with the formula H2O3. This formula does not follow the valence rule in chemistry and therefore does not exist in reality.
However, you might be confusing it with H2O2, which is the formula for oxygenated water or also known as hydrogen peroxide in English. Hydrogen peroxide has a molar mass of 34.02 and an atomic mass of 1.01 for hydrogen and 16 for oxygen.
The H2O2 molecule consists of two hydrogen atoms and two oxygen atoms. It does not form ions in its pure form but can polarize to form ions.
In terms of properties, H2O2 is a colorless liquid with a fairly distinctive smell. It has a mild acidic characteristic with a pH below 7. In chemistry, it is known for its role as a strong oxidizing agent.
H2O2 can react with metals, acids, non-metals and salts in various chemical reactions.
As for its preparation, H2O2 is generally made in the laboratory through the process of water oxidation by electricity. Industrially, it is often prepared by the anthraquinone method.