2.4. Sucrose crystal structure
Crystal habit is the term used to describe the appearance and shape of a crystal (Morel du Boil 1985). The conditions during growth of the crystal influence the development and morphology of the crystal. The morphology of a crystal grown in the presence of impurities is influenced greatly at the faces of the crystal most affected by the adsorption of impurities (Morel du Boil 1985). Therefore, the presence of impurities was thought to possess the greatest influence on crystal growth and morphology, while other factors were thought to possess a less significant effect.
“Crystal elongation is a term which can be used to describe the shape of a crystal when the ratio of the crystal lengths in any two specified axial directions is larger than that usually observed under similar crystallisation conditions” (Morel du Boil 1991). Vane (1981) highlighted that the natural shape of a pure sucrose crystal grown in water is roughly twice as long in the b-direction (y) as in the c-direction (z) based on basic rate data derived from Smythe (1967a). Therefore, normal crystals have a y/z ratio of about two (Morel du Boil 1985). Crystals that exhibit c-axis elongation have a y/z ratio less than two, while a y/z ratio greater than 2 indicates b-axis elongation (Morel du Boil 1985). …show more content…
Sucrose morphology
The anhydrous form of sucrose is characterised by a two-fold axis of symmetry belonging to the sphenoidic class of the monoclinic system (Smythe 1967c). The axis of symmetry which is asymmetrical in length, coincides with the crystallographic b-axis (Figure
Crystal habit is the term used to describe the appearance and shape of a crystal (Morel du Boil 1985). The conditions during growth of the crystal influence the development and morphology of the crystal. The morphology of a crystal grown in the presence of impurities is influenced greatly at the faces of the crystal most affected by the adsorption of impurities (Morel du Boil 1985). Therefore, the presence of impurities was thought to possess the greatest influence on crystal growth and morphology, while other factors were thought to possess a less significant effect.
“Crystal elongation is a term which can be used to describe the shape of a crystal when the ratio of the crystal lengths in any two specified axial directions is larger than that usually observed under similar crystallisation conditions” (Morel du Boil 1991). Vane (1981) highlighted that the natural shape of a pure sucrose crystal grown in water is roughly twice as long in the b-direction (y) as in the c-direction (z) based on basic rate data derived from Smythe (1967a). Therefore, normal crystals have a y/z ratio of about two (Morel du Boil 1985). Crystals that exhibit c-axis elongation have a y/z ratio less than two, while a y/z ratio greater than 2 indicates b-axis elongation (Morel du Boil 1985). …show more content…
Sucrose morphology
The anhydrous form of sucrose is characterised by a two-fold axis of symmetry belonging to the sphenoidic class of the monoclinic system (Smythe 1967c). The axis of symmetry which is asymmetrical in length, coincides with the crystallographic b-axis (Figure