Which statement is incorrect

Options

A. Borazine has a 3D-layer structure like that of graphite
B. Boric acid has a hydrogen bonded layer structure in the solid state
C. Borazine molecule is `(BN)_(3)`
D. `[Al_(6)O_(18)]^(18-)` contains a non-polar `Al_(6)O_(6)`-ring

Explanation

To determine which statement is incorrect, we will analyze each of the provided statements one by one.

### Step 1: Analyze the first statement
**Statement:** Borazine has a 3D layer structure like that of graphite.
**Analysis:** Borazine (B3H6N3) does not have a layered structure like graphite. Instead, boron nitride (BN) has a graphite-like structure. Therefore, this statement is incorrect.

### Step 2: Analyze the second statement
**Statement:** Boric acid has a hydrogen bonded layer structure in the solid state.
**Analysis:** Boric acid (H3BO3) does indeed have a layered structure stabilized by hydrogen bonding in its solid state. This statement is correct.

### Step 3: Analyze the third statement
**Statement:** Borazine molecule is BN3.
**Analysis:** The correct formula for borazine is B3H6N3, not BN3. Therefore, this statement is also incorrect.

### Step 4: Analyze the fourth statement
**Statement:** Al6O18^2- contains a non-polar Al6O6 ring.
**Analysis:** The structure of Al6O18^2- includes AlO4 tetrahedra, and it does not contain a non-polar Al6O6 ring. Therefore, this statement is incorrect.

### Conclusion
After analyzing all statements:
1. The first statement is incorrect.
2. The second statement is correct.
3. The third statement is incorrect.
4. The fourth statement is incorrect.

Thus, the statements that are incorrect are the first, third, and fourth. However, since the question asks for which statement is incorrect, the first statement is the most relevant to answer.

### Final Answer
The incorrect statement is: **Borazine has a 3D layer structure like that of graphite.**