Crystal Symmetry Definitions
Crystals possess unique structural arrangements that define their symmetry. Key terms relate to how different parts of the crystal relate to each other through symmetry operations like inversion or reflection.
Centrosymmetric Crystal Properties
A centrosymmetric crystal has a center of symmetry. If you draw a line from any point on the crystal's surface through the exact center and extend it the same distance, you will find an identical point on the opposite side. This means features like faces appear mirrored across the center. For instance, a face on one side would be opposite an identical face on the other.
Non-centrosymmetric Crystal Properties
Conversely, a non-centrosymmetric crystal lacks a center of symmetry. In such crystals, the symmetry operations do not lead to identical points or features being diametrically opposite. The question describes a specific case: "a face on one side is opposite to a point on the other". This condition indicates the absence of a center of symmetry, where a face doesn't have an identical face opposite it.
Analyzing Crystal Definitions
Let's examine the options in light of the description:
- Enantiomorphous: These are crystals that are non-superimposable mirror images of each other (chiral). This doesn't directly match the face-to-point description.
- Centrosymmetric: Ruled out because a face opposite a point violates the definition of having an identical face opposite.
- Non-centrosymmetric: This perfectly matches the description of having a face opposite a point, indicating a lack of central symmetry.
- Hemihedral: This describes crystals showing fewer faces than expected for their symmetry class, not specifically a face-opposite-point relationship.
Therefore, the description directly corresponds to the definition of a non-centrosymmetric crystal.
Similar Questions
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Many natural disasters are caused by the volcanic activity occurring in the island arc systems.
Reason (R) : The fissure type volcanism causes the erupted lava to spread over wide areas.
In the light of the above statements, choose the most appropriate answer from the options given below :
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Gypsum has lower density than anhydrite.
Reason (R) : Hydrated minerals tend to expand many times the original volume of the anhydrous minerals.
In the light of the above statements, choose the most appropriate answer from the options given below :
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Drumlins show features opposite to those of Roches Moutonnees.
Reason (R) : The stoss side is steep and the lee side is roughened.
In the light of the above statements, choose the most appropriate answer from the options given below :
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : In a hand specimen quartz can be easily distinguished from orthoclase.
Reason (R) : Orthoclase has lower refractive index than quartz.
In the light of the above statements, choose the most appropriate answer from the options given below :
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : L waves are responsible for majority of the destructive earthquakes.
Reason (R) : They are the surface waves and develope in the immediate vicinity of the epicenter.
In the light of the above statements, choose the most appropriate answer from the options given below :
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : All continents were united together in the past.
Reason (R) : The Gangamopteris and Glossopteris flora have been found on all the southern continents.
In the light of the above statements, choose the most appropriate answer from the options given below :
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : A dip-slip fault can be a wrench fault.
Reason (R) : Along a dip fault, the net slip can be equal to strike-slip, dip-slip or oblique-slip.
In the light of the above statements, choose the most appropriate answer from the options given below :
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Chronostratigraphy is concerned with the mutual time relationship of strata.
Reason (R) : Formation, member and bed are units of chronostratigraphy.
In the light of the above statements, choose the most appropriate answer from the options given below :
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : The angle between any two faces of a crystal is termed as interfacial angle.
Reason (R) : The interfacial angles of corresponding faces of different crystals are constant if they have same chemical composition and measurements are taken at same temperature.
In the light of the above statements, choose the most appropriate answer from the options given below :
Match List - I with List - II.
List - I
Crystal SystemList - II
CharacteristicsA. Monoclinic I. 4 triads B. Tetragonal II. 3 diads C. Orthorhombic III. 1 tetrad D. Cubic IV. 1 diad Choose the correct answer from the options given below :
Important Questions from Mixed Topic (CUET PG)
- Kalpsutra, the illustrated canonical text is from:-
- The Harappan city almost exclusively devoted to craft production was-:
- Mohandas Karamchand Gandhi launched quit India movement after the failure of:-
- The "Objectives Resolution" was introduced in constituent assembly by:-
- Who among the following was not a member of the constituent assembly:-
