What is it about?

As a result of research into the behaviour of sugars in processes involved in chocolate manufacture, we have discovered a new crystalline form of lactose. Initially identified using powder X-ray diffraction, we were able to characterise the 3D structure of this new crystal form using single-crystal X-ray diffraction from a microcrystal. This is the second crystalline form of αβ-D-lactose to be identified and it has a high degree of structural 3D-similarity to the previously identified form. The crystal structure information file (CIF) can be downloaded as supplementary information from the IUCr's publication web site.

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Why is it important?

Polymorphism (the existence of more than one crystal form of a compound) is an important phenomenon in many areas, such as pharmaceuticals, food, pigments and dyes, as the physical properties of the compound (such as melting point and solubility) depend upon the crystal form. Lactose is well known to exist in a number of crystalline forms and the discovery of this new form of αβ-D-lactose further populates the 'lactose structural landscape', potentially aiding industries that rely upon a thorough understanding of lactose and its properties in the solid state.


This work illustrates the power of using powder and single-crystal X-ray diffraction in combination to fully characterise the 3D crystal structure of a previously unreported material. Furthermore, it illustrates how computational methods (specifically, periodic density functional theory calculations) can be used to help "fine tune" the details of the X-ray crystal structure. The finding was certainly surprising given that lactose is so widely used in everything from baking to pharmaceutical tablet making, and so widely studied as a result

Kenneth Shankland
University of Reading

Read the Original

This page is a summary of: A new crystalline form of αβ-D-lactose prepared by oven drying a concentrated aqueous solution of D-lactose, Acta Crystallographica Section C Structural Chemistry, June 2019, International Union of Crystallography, DOI: 10.1107/s2053229619008210.
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