{"id":2251,"date":"2025-05-09T17:16:52","date_gmt":"2025-05-09T17:16:52","guid":{"rendered":"https:\/\/yaveni.com\/blog\/?p=2251"},"modified":"2025-05-09T17:16:54","modified_gmt":"2025-05-09T17:16:54","slug":"draw-a-molecular-orbital-diagram-for-crco6","status":"publish","type":"post","link":"https:\/\/gaviki.com\/blog\/draw-a-molecular-orbital-diagram-for-crco6\/","title":{"rendered":"draw a molecular orbital diagram for Cr(CO)6"},"content":{"rendered":"\n

draw a molecular orbital diagram for Cr(CO)6<\/p>\n\n\n\n

The correct answer and explanation is :<\/strong><\/mark><\/p>\n\n\n\n

Molecular Orbital Diagram for Cr(CO)\u2086<\/strong><\/h3>\n\n\n\n

To construct the molecular orbital (MO) diagram for chromium hexacarbonyl, Cr(CO)\u2086<\/strong>, we must consider the interaction between the metal d-orbitals<\/strong> and the ligand group orbitals<\/strong> derived from the six CO ligands. Cr(CO)\u2086 is an octahedral<\/strong> complex, and the bonding is best understood using molecular orbital theory<\/strong> based on symmetry-adapted linear combinations (SALCs) of ligand orbitals.<\/p>\n\n\n\n

\n\n\n\n

1. Electron Configuration:<\/strong><\/h4>\n\n\n\n
    \n
  • Chromium in Cr(CO)\u2086 is in the 0 oxidation state<\/strong>.<\/li>\n\n\n\n
  • Atomic number of Cr = 24 \u2192 [Ar] 3d\u2075 4s\u00b9 \u2192 in complex, 3d\u2076 (after accepting 6 electrons from CO ligands).<\/li>\n<\/ul>\n\n\n\n
    \n\n\n\n

    2. Ligand Orbitals (CO):<\/strong><\/h4>\n\n\n\n

    Each CO ligand donates:<\/p>\n\n\n\n

      \n
    • One \u03c3-donor<\/strong> orbital from the lone pair on carbon.<\/li>\n\n\n\n
    • One \u03c0-acceptor<\/strong> orbital via the empty \u03c0* orbitals.<\/li>\n<\/ul>\n\n\n\n

      For 6 ligands:<\/p>\n\n\n\n

        \n
      • 6 \u03c3-donor orbitals<\/strong> form SALCs of a\u2081g<\/strong>, t\u2081u<\/strong>, eg<\/strong> symmetry.<\/li>\n\n\n\n
      • 6 \u03c0-acceptor orbitals<\/strong> form SALCs of t\u2082g<\/strong>, etc.<\/li>\n<\/ul>\n\n\n\n
        \n\n\n\n

        3. Metal Orbitals (Cr):<\/strong><\/h4>\n\n\n\n
          \n
        • 3d (t\u2082g + eg)<\/strong>, 4s (a\u2081g)<\/strong>, and 4p (t\u2081u)<\/strong> orbitals.<\/li>\n<\/ul>\n\n\n\n
          \n\n\n\n

          4. MO Interactions:<\/strong><\/h4>\n\n\n\n
          Ligand SALC<\/th>Metal Orbital<\/th>Type of Bonding<\/th><\/tr><\/thead>
          a\u2081g<\/td>4s<\/td>\u03c3-bonding<\/td><\/tr>
          t\u2081u<\/td>4p<\/td>\u03c3-bonding<\/td><\/tr>
          eg<\/td>3d (eg)<\/td>\u03c3-bonding<\/td><\/tr>
          t\u2082g<\/td>3d (t\u2082g)<\/td>\u03c0-backbonding<\/strong><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
            \n
          • \u03c3-donation<\/strong> from CO fills lower-energy bonding orbitals.<\/li>\n\n\n\n
          • \u03c0-backbonding<\/strong>: metal t\u2082g electrons are donated into CO\u2019s \u03c0* orbitals, stabilizing the complex and weakening the C\u2261O bond.<\/li>\n<\/ul>\n\n\n\n
            \n\n\n\n

            5. Electron Counting:<\/strong><\/h4>\n\n\n\n
              \n
            • Cr\u2070 contributes 6 valence electrons.<\/li>\n\n\n\n
            • Each CO contributes 2 electrons \u00d7 6 = 12 electrons.<\/li>\n\n\n\n
            • Total = 18 electrons<\/strong> \u2192 follows the 18-electron rule<\/strong>.<\/li>\n<\/ul>\n\n\n\n
              \n\n\n\n

              Molecular Orbital Diagram:<\/h3>\n\n\n\n
                      \u03c3* eg\n        \u03c3* t1u\n        \u03c0* (from CO) \u2190 \u03c0-backbonding \u2190 t2g (Cr 3d)\n        Nonbonding t2g (partially filled)\n        \u03c3 eg (bonding)\n        \u03c3 t1u (bonding)\n        \u03c3 a1g (bonding)<\/code><\/pre>\n\n\n\n
                \n
              • Bonding MOs<\/strong>: a\u2081g, t\u2081u, eg<\/li>\n\n\n\n
              • Non-bonding\/weakly bonding<\/strong>: t\u2082g (\u03c0-backbonding region)<\/li>\n\n\n\n
              • Antibonding<\/strong>: t\u2081u*, eg*<\/li>\n<\/ul>\n\n\n\n
                \n","protected":false},"excerpt":{"rendered":"
                draw a molecular orbital diagram for Cr(CO)6 The correct answer and explanation is : Molecular Orbital Diagram for Cr(CO)\u2086 To construct the molecular orbital (MO) diagram for chromium hexacarbonyl, Cr(CO)\u2086, we must consider the interaction between the metal d-orbitals and the ligand group orbitals derived from the six CO ligands. Cr(CO)\u2086 is an octahedral complex, […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[],"class_list":["post-2251","post","type-post","status-publish","format-standard","hentry"],"_links":{"self":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/2251","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/comments?post=2251"}],"version-history":[{"count":1,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/2251\/revisions"}],"predecessor-version":[{"id":2252,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/2251\/revisions\/2252"}],"wp:attachment":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/media?parent=2251"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/categories?post=2251"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/tags?post=2251"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}