Space-filling models of the hydrogen peroxide molecule

In aqueous solutions, hydrogen peroxide differs from the pure substance due to the effects of hydrogen bonding between water and hydrogen peroxide molecules. Hydrogen peroxide and water form a eutectic mixture, exhibiting freezing-point depression down as low as -56 degrees Celsius; pure water has a freezing point of 0 degrees Celsius and pure hydrogen peroxide of -0.43 degrees Celsius. The boiling point of the same mixtures is also depressed in relation with the mean of both boiling points. It occurs at 114 degrees Celsius. This boiling point is 14 degrees Celsius greater than that of pure water and 36.2 °C less than that of pure hydrogen peroxide. Its melting point is also fairly high, being comparable to that of hydrazine and water, with only hydroxylamine crystallising significantly more readily, indicative of particularly strong hydrogen bonding. Diphosphane and hydrogen disulfide exhibit only weak hydrogen bonding and have little chemical similarity to hydrogen peroxide. Structurally, the analogues all adopt similar skewed structures, due to repulsion between adjacent lone pairs. Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: [e-mail], Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China