Given that a certain organoaluminum compound contains the anion $\mathrm { \small { [ A l _ { 7 } O _ { 6 } C _ { 1 6 } H _ { 4 8 } ] } ^ { - } }$, in which both aluminum and oxygen have two different chemical environments, which of the following statements is correct:
已知某有机铝化合物中含有 $\mathrm { { [ A l _ { 7 } O _ { 6 } C _ { 1 6 } H _ { 4 8 } ] } ^ { - } }$ 阴离子，其中的铝和氧都有两种不同的化学环境，下列说法正确的是：
The aluminum-aluminum bond exists in this anion.
The anion contains 3 six-membered rings.
Two chemical environments have 3 and 4 aluminum atoms respectively.
The anion contains both two-coordinate and three-coordinate oxygen atoms.
There are a total of 3 carbon-oxygen bonds in this anion.
The anion contains an aluminum atom coordinated to 4 oxygen atoms.
该阴离子中存在铝-铝键
该阴离子中有且仅有2个六元环
两种化学环境的铝原子分别有3个和4个
该阴离子中有二配位和三配位的氧原子
该阴离子中一共有3根碳氧键
该阴离子中存在与4个氧原子配位的铝原子
Based on the carbon-to-hydrogen ratio, it is speculated that all carbon and hydrogen exist in the form of methyl (or methoxy) groups and do not participate in the construction of the framework, while the framework can only consist of 7 aluminum atoms and 6 oxygen atoms. Since the aluminum-oxygen bond is very stable, aluminum and oxygen should exist alternately in the framework. According to the principle of maximizing symmetry, it is inferred that the framework consists of three six-membered rings.

<Checkpoint>[The framework contains three six-membered rings](1)</Checkpoint>

One aluminum atom is shared by 3 rings, and the other aluminum and oxygen atoms are arranged alternately around it. Thus, three oxygen atoms connect three aluminum atoms, and the other three oxygen atoms each connect two aluminum atoms. Aluminum has a +3 valence, with a total of 21 positive charges, so 22 negative charges are required. The three oxygen atoms connecting three aluminum atoms have a total of 6 negative charges, so the remaining 16 negative charges are from 13 methyl groups and 3 methoxy groups. All aluminum atoms have a tetrahedral configuration, so the 6 aluminum atoms at the edges each connect to 2 methyl groups, and the central aluminum atom connects to 1 methyl group, resulting in the structure of the anion:

<MultiModal>![The structure of the anion is C[O-]1[Al+](C)(C)[O-]([Al+](C)(C)[O-](C)[Al+]2(C)C)[Al]([O-]2[Al+](C)(C)[O-](C)[Al+]3(C)C)(C)[O-]3[Al+]1(C)C](/media/uploads/37114333-3bc7-47db-8d63-f52275bc963f.png)</MultiModal>

<Checkpoint>[The structure of the anion is [C[O-]1[Al+](C)(C)[O-]([Al+](C)(C)[O-](C)[Al+]2(C)C)[Al]([O-]2[Al+](C)(C)[O-](C)[Al+]3(C)C)(C)[O-]3[Al+]1(C)C]]](2)</Checkpoint>

There are two chemical environments for aluminum atoms: 1 aluminum atom is coordinated by 2 methyl groups and 2 oxygen atoms, and 5 aluminum atoms are coordinated by 1 methyl group and 3 oxygen atoms. Options A and C are incorrect.
There are two chemical environments for oxygen atoms: 3 oxygen atoms are coordinated by 3 aluminum atoms, and 3 oxygen atoms are coordinated by 2 aluminum atoms and 1 methyl group. Option E is correct, and options D and F are incorrect.
There are three six-membered rings in the structure, so option B is incorrect.
根据碳氢比例，推测碳和氢全部以甲基（或甲氧基）形式存在，不参与骨架的构建，而骨架只能是7个铝原子和6个氧原子。而铝氧键非常稳定，因此铝和氧在骨架种应该间隔存在。根据对称性尽可能高的原则，推断骨架为三个六元环。

<Checkpoint>[骨架含有三个六元环](1)</Checkpoint>

其中一个铝原子为3个环共用，其他的铝和氧在四周间隔排列，由此有三个氧原子是连接三个铝的，另外三个氧原子各连接两个铝。铝为+3价，共有21个正电荷，因此需要22个负电荷。三个连接三个铝的氧原子共有6个负电荷，因此其余16个负电荷为13个甲基和3个甲氧基。所有铝均为四面体构型，则边缘的6个铝各连接2个甲基，中心的铝连接1个甲基，这样就得到了阴离子的结构：

<MultiModal>![阴离子的结构为C[O-]1[Al+](C)(C)[O-]([Al+](C)(C)[O-](C)[Al+]2(C)C)[Al]([O-]2[Al+](C)(C)[O-](C)[Al+]3(C)C)(C)[O-]3[Al+]1(C)C](/media/uploads/37114333-3bc7-47db-8d63-f52275bc963f.png)</MultiModal>

<Checkpoint>[阴离子的结构为[C[O-]1[Al+](C)(C)[O-]([Al+](C)(C)[O-](C)[Al+]2(C)C)[Al]([O-]2[Al+](C)(C)[O-](C)[Al+]3(C)C)(C)[O-]3[Al+]1(C)C]]](2)</Checkpoint>

铝原子有两种化学环境：1个铝原子被2个甲基和2个氧原子配位，5个铝原子被1个甲基和3个氧原子配位。A和C选项错误。
氧原子有两种化学环境：3个氧原子被3个铝原子配位，3个氧原子被2个铝原子和1个甲基配位。E选项正确，D和F选项错误。
该结构中有三个六元环，B选项错误。