Related Experiment Video
Updated: Jun 24, 2026
06:27
Sandy Soil Improvement through Microbially Induced Calcite Precipitation (MICP) by Immersion
Published on: September 12, 2019
How much water does calcined gypsum contain?
1BASF SE, Polymer Research-Polymer Physics, 67056 Ludwigshafen, Germany.
Angewandte Chemie (International Ed. in English)
|April 8, 2009
Summary
This study reveals the ordered structure of water molecules within calcined gypsum (CaSO(4)0.5 H(2)O). Single-crystal analysis and DFT calculations confirm this atomic arrangement, settling long-standing questions about gypsum
Area of Science:
- Materials Science
- Crystallography
- Chemistry
Background:
- Gypsum has been a key construction material for thousands of years.
- The precise structure and water content of calcined gypsum (CaSO(4)0.5 H(2)O) have remained subjects of scientific debate.
Purpose of the Study:
- To elucidate the definitive structure of water within calcined gypsum.
- To resolve ambiguities regarding the atomic arrangement and hydration state of this common building material.
Main Methods:
- Single-crystal structure analysis was employed to determine the atomic positions.
- Density Functional Theory (DFT) calculations were utilized to validate the proposed structural model.
Main Results:
- A definitive, ordered model for the water content in calcined gypsum was established.
- The proposed structure was rigorously confirmed through independent computational methods (DFT).
Conclusions:
- The study provides a clear, ordered structural model for water in calcined gypsum.
- This resolves longstanding questions about the hydration of gypsum, impacting materials science and construction.
More Related Videos
Related Concept Videos
01:24Hydration of Cement
Hydration of cement is a chemical reaction between cement particles and water. This process occurs primarily through two mechanisms: through-solution and topochemical. In the through-solution process, anhydrous compounds dissolve into their constituents, hydrates form in the solution, and then precipitate from the supersaturated solution. The topochemical process involves solid-state reactions at the cement particle surface. The through-solution process dominates the topochemical process at the...
01:18Porosity in Cement Paste
The porosity of concrete is a measure of the void spaces within its structure. These spaces impact its strength and durability significantly. When water and cement interact, a chemical reaction called hydration creates a semi-solid paste. This paste includes combined water, making up approximately 23% of the cement's dry mass, and gel water, which fills minuscule voids known as gel pores, accounting for about 28% of the cement gel volume.
The balance of water to cement in the mix is critical—it...
The balance of water to cement in the mix is critical—it...
01:29Strength and Heat of Hydration
The hydration of cement is an exothermic reaction in which heat is generated as cement hydrates. This heat of hydration is critical to cement's strength development. The rate at which this heat is generated affects the temperature rise, with a majority of the heat being released early in the hydration process, half within the first three days, and about 75% within the first week.
The heat of hydration for each cement compound is significant; for instance, tricalcium aluminate (C3A) and...
The heat of hydration for each cement compound is significant; for instance, tricalcium aluminate (C3A) and...
01:29Sulfate Attack on Concrete
Sulfate attack on concrete is a deterioration process characterized by a whitish discoloration beginning at the edges and corners, accompanied by cracking and spalling. This phenomenon occurs when sulfates react with the components of hardened concrete, forming compounds like calcium sulfate and calcium sulfoaluminate which occupy more space than the substances they replace, causing the concrete to expand and disrupt.
Sulfates from sources like soil, groundwater, or industrial effluents...
Sulfates from sources like soil, groundwater, or industrial effluents...
01:21Portland Cement
Portland cement is the essential binding ingredient in concrete, made from finely ground materials including lime, iron, silica, and alumina. Lime is derived primarily from limestone, marble, marl, seashells, and clays, which also supply iron and alumina, while silica is sourced from sand, chalk, and bauxite. Contemporary manufacturing of Portland cement is a significant source of carbon dioxide emissions, prompting research into reducing its content in concrete through alternative...
03:34Ionic Compounds: Formulas and Nomenclature
An element composed of atoms that readily lose electrons (a metal) can react with an element composed of atoms that readily gain electrons (a nonmetal) to produce ions through complete electron transfer. The compound formed by this transfer is stabilized by the electrostatic attractions (ionic bonds) between the oppositely charged ions.