Identify the incorrect characteristic of carbenes,: `CR_2`

Options

A. contain carbon atom with only six valence electrons
B. neutral species
C. very reactive
D. normally neocleophylic

Answer

To identify the incorrect characteristic of carbenes, we need to analyze each of the provided statements regarding their properties.

### Step-by-Step Solution:

1. **Understanding Carbenes**:
- Carbenes are species that contain a carbon atom with two bonds and two non-bonding electrons (lone pairs). This gives them a total of six valence electrons.

2. **Analyzing the Characteristics**:
- **Characteristic 1**: "It contains carbon atom with only 6 valence electrons."
- This statement is **correct**. Carbenes have a carbon atom that is surrounded by six valence electrons (two from the bonds and four from the lone pairs).

- **Characteristic 2**: "It is a neutral species."
- This statement is also **correct**. Carbenes are neutral because they do not carry any formal charge.

- **Characteristic 3**: "It is very reactive."
- This statement is **correct** as well. Carbenes are known to be highly reactive due to their electron deficiency and the presence of lone pairs.

- **Characteristic 4**: "It is normally nucleophilic."
- This statement is **incorrect**. While carbenes can act as nucleophiles in some reactions, they can also act as electrophiles. They are not exclusively nucleophilic due to their electron-deficient nature.

3. **Conclusion**:
- The incorrect characteristic of carbenes is that they are "normally nucleophilic." This is misleading because carbenes can function as both electrophiles and nucleophiles depending on the reaction context.

### Final Answer:
The incorrect characteristic of carbenes is: **"It is normally nucleophilic."**

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