Related Experiment Video
Updated: Jul 13, 2026

Optimization of Crystal Growth for Neutron Macromolecular Crystallography
Published on: March 13, 2021
An extended phase transition in crystalline L-cysteine near 70 K
Igor E Paukov1, Yulia A Kovalevskaya, Valeri A Drebushchak
1Institute of Inorganic Chemistry SB RAS, Lavrent'eva 3, Novosibirsk, 630090, Russia. paukov@che.nsk.su
Abstract:
An anomaly of heat capacity near 70 K was registered in the crystalline L-cysteine (orthorhombic polymorph) by adiabatic calorimetry as a small, 3-5% height, diffuse "jump", or a wide "hump" accompanied by the substantial increase in the thermal relaxation time. The Cp(T) dependence is characteristic for a transformation extended over a wide temperature range and sensitive to the thermal prehistory of the sample, that can be interpreted as nonsimultaneous changes in the dynamics and the orientation of the numerous thiol groups in the structure. The measurements of the cell parameters and cell volume on cooling suggest that a discontinuity in their values over the transition point exists.
Related Concept Videos
Phase Transitions: Melting and Freezing
Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
Phase Transitions
Phase Transitions
Crystal Growth: Principles of Crystallization
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent – the...
Metallic Solids
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...

