What is the oxidation state of chromium AND the coordination number for the complex, [Cr(en)2(OH)2]Cl

Question

BlackTom AI · Accepted Answer

Each ethylenediamine (en) is a neutral bidentate ligand, so it donates two donor atoms to the metal. Hydroxo (OH) ligands are monodentate with a charge of −1. The coordination number counts donor atoms directly bonded to the metal, and the oxidation state is determined by charge balance between the metal and coordinated ligands plus any counterions.

Step-by-step reasoning and calculation:
1. Identify ligand charges and denticity:
   - en: neutral, charge = 0, denticity = 2 (two donor atoms per en).
   - OH: each is −1, denticity = 1.
   - The formula is [Cr(en)2(OH)2]Cl, so there is one Cl− counterion outside the coordination sphere.

2. Determine the charge on the complex ion:
   - The salt is neutral overall, so the complex ion [Cr(en)2(OH)2] must have charge +1 to balance one Cl−.

3. Set up oxidation-state equation (let x = oxidation state of Cr):
   - x + (2 × 0 for the two en) + (2 × −1 for the two OH) = +1
   - x + 0 − 2 = +1
   - x − 2 = +1
   - x = +3

(Alternatively include the external Cl−: x + 0 − 2 + (−1 for Cl−) = 0 → x − 3 = 0 → x = +3.)

4. Find coordination number:
   - 2 en ligands × 2 donor atoms each = 4 donor atoms
   - 2 OH ligands × 1 donor atom each = 2 donor atoms
   - Total coordination number = 4 + 2 = 6

Why the correct answer is correct:
- Charge balance gives Cr in the +3 oxidation state, and counting donor atoms gives coordination number 6. Thus the pair is 3+ and 6.

Why other options are incorrect:
- Options a and b (coordination number 4) ignore that each en is bidentate (contributes 2 donor atoms each).
- Option d (Cr 5+) does not satisfy charge balance with the given ligand charges and counterion.

Conclusion: The oxidation state is Cr(III) (3+) and the coordination number is 6, matching answer c. 3+ AND 6.

What is the oxidation state of chromium AND the coordination number for the complex, [Cr(en)2(OH)2]Cl单项选择题

类似问题

Which of the following is a negatively (-1) charged ligand?

What is the coordination number, geometry and oxidation state of Pt in:

Consider the coordination complex below: The counter ion is:

What is the coordination number, geometry and oxidation state of Ni in:

Which of the following complexes is the active form of cis-platin?[Fill in the blank]

Which ligands are in the inner coordination sphere for [PtBr(NH3)3]Br∙H2O ?

Based on your answer to the previous question, choose which energy profile diagram (reaction coordinate diagram) best suits the above class of reaction you have chosen. Note that TS = Transition State, I = Intermediate

Which following statement is incorrect. Crystal field stabilisation energy depends on;

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单