Elemental carbon appears in many structural forms or allotropes . Three of these formssare crystalline -diamond ,graphite and the recentluy discovered fullerne (bucky ball ) -while more than `40` others including coke and carbon black ae amorphous . Now there seems to be set afourth crystalline allotrope of carbon. reported in `1995` by Lagow at the University of Texas .
Structures fodifferentallotropes of carbon have been compared . Which represents incorrect comparison ?

Options

A. allotrope discovered in ` 1995` sp-hybridised carbon
B. bucky ball sp-hybridised carbon
C. graphite sp2-hybridised carbon
D. diamond sp3-hybridised carbon

Answer

To determine which comparison of the allotropes of carbon is incorrect, we will analyze the hybridization states of the different allotropes mentioned in the question.

### Step-by-Step Solution:

1. **Identify the Allotropes of Carbon**: The question mentions several allotropes of carbon: diamond, graphite, buckyball (fullerene), and a newly discovered allotrope from 1995.

2. **Determine the Hybridization of Each Allotrope**:
- **Diamond**: In diamond, each carbon atom is bonded to four other carbon atoms in a tetrahedral geometry. This results in sp³ hybridization.
- **Graphite**: In graphite, each carbon atom is bonded to three other carbon atoms in a planar structure, leading to sp² hybridization.
- **Buckyball (Fullerene)**: Buckyballs (C₆₀) consist of carbon atoms arranged in a spherical shape where each carbon atom is bonded to three other carbon atoms, which also indicates sp² hybridization.
- **New Allotrope (Polyene)**: The new allotrope discovered in 1995 is polyene, which has sp hybridized carbon atoms.

3. **Analyze the Given Comparisons**:
- **Comparison 1**: The new allotrope discovered in 1995 has sp hybridized carbon. (True)
- **Comparison 2**: Buckyball has sp hybridized carbon. (False; it has sp² hybridization)
- **Comparison 3**: Graphite is sp² hybridized. (True)
- **Comparison 4**: Diamond is sp³ hybridized. (True)

4. **Identify the Incorrect Comparison**: From the analysis, the second comparison regarding the buckyball is incorrect because it states that buckyball has sp hybridized carbon, while it actually has sp² hybridization.

### Conclusion:
The incorrect comparison is **Comparison 2**: "Buckyball has sp hybridized carbon."

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