Hydrogen bonding in solids: correlation of spectroscopic and crystallographic data. A. Novak, Laboratoire de Chimie Physique, C.N.R.S., Thiais, France. This paper discusses the classification of hydrogen bonds, their spectroscopic and crystallographic characteristics, and the relationships between hydrogen bond properties and vibrational frequencies. The introduction explains how hydrogen bonding modifies the potential energy of an AH group, leading to changes in vibrational levels and shifts in stretching bands. The paper also describes the isotope effect and the position of the proton in hydrogen bonds, highlighting the double minimum and single symmetric minimum types of hydrogen bonds. Section I introduces the concept of hydrogen bonding and its effects on the potential energy of AH groups. Section II explores the correlations between vibrational frequencies and distances in hydrogen bonds, including the relationships between AH stretching frequency and R(A..B) distance, O–H stretching frequency and r(O–H) distance, and the stretching and bending frequencies of AH groups. Section III discusses the isotope effect and the position of the proton, focusing on the vAH/vAD isotopic frequency ratio and its correlation with R(A..B) distance. The paper concludes with a summary of the key findings and their implications for understanding hydrogen bonding in solids. The study uses infrared and Raman spectroscopy, as well as neutron and X-ray diffraction, to analyze the structural and vibrational properties of hydrogen bonds. The results show that hydrogen bond strength can be estimated using criteria such as AH stretching frequency and distances between atoms involved in the bond. The paper emphasizes the importance of these correlations in understanding the behavior of hydrogen bonds in solids.Hydrogen bonding in solids: correlation of spectroscopic and crystallographic data. A. Novak, Laboratoire de Chimie Physique, C.N.R.S., Thiais, France. This paper discusses the classification of hydrogen bonds, their spectroscopic and crystallographic characteristics, and the relationships between hydrogen bond properties and vibrational frequencies. The introduction explains how hydrogen bonding modifies the potential energy of an AH group, leading to changes in vibrational levels and shifts in stretching bands. The paper also describes the isotope effect and the position of the proton in hydrogen bonds, highlighting the double minimum and single symmetric minimum types of hydrogen bonds. Section I introduces the concept of hydrogen bonding and its effects on the potential energy of AH groups. Section II explores the correlations between vibrational frequencies and distances in hydrogen bonds, including the relationships between AH stretching frequency and R(A..B) distance, O–H stretching frequency and r(O–H) distance, and the stretching and bending frequencies of AH groups. Section III discusses the isotope effect and the position of the proton, focusing on the vAH/vAD isotopic frequency ratio and its correlation with R(A..B) distance. The paper concludes with a summary of the key findings and their implications for understanding hydrogen bonding in solids. The study uses infrared and Raman spectroscopy, as well as neutron and X-ray diffraction, to analyze the structural and vibrational properties of hydrogen bonds. The results show that hydrogen bond strength can be estimated using criteria such as AH stretching frequency and distances between atoms involved in the bond. The paper emphasizes the importance of these correlations in understanding the behavior of hydrogen bonds in solids.