{
  "id": "electronegativity",
  "version": "83af54dd5c95",
  "status": "published",
  "name": "Electronegativity Calculator",
  "question": "What is the electronegativity gap?",
  "summary": "Gives the Pauling electronegativity of two elements and the difference between them, with the bond type it suggests (pure covalent, polar covalent or ionic) and which atom takes the partial negative charge.",
  "category": "chemistry",
  "subcategory": "atoms",
  "url": "https://www.acalculator.org/chemistry/electronegativity-calculator",
  "markdown": "https://www.acalculator.org/chemistry/electronegativity-calculator.md",
  "kind": "function",
  "method": "ΔEN = |EN(A) − EN(B)| with Pauling electronegativities (OpenStax Figure 7.6). Guide: ΔEN below 0.4 pure covalent, 0.4 to 1.8 polar covalent, above 1.8 ionic. The more electronegative atom takes the partial negative charge.",
  "assumptions": [
    "Pauling electronegativities to one decimal as OpenStax prints them; the noble gases, the lanthanides (given only as 1.0 to 1.2), the actinides after uranium (1.3 to 1.4) and the elements after them have no single value and are not listed.",
    "The bond type is a rough guide with many exceptions: H–F (1.9) is polar covalent and MnI₂ (1.0) is ionic."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "a": {
        "title": "First element",
        "description": "The first atom of the bond.",
        "type": "string",
        "enum": [
          "H",
          "Li",
          "Be",
          "B",
          "C",
          "N",
          "O",
          "F",
          "Na",
          "Mg",
          "Al",
          "Si",
          "P",
          "S",
          "Cl",
          "K",
          "Ca",
          "Sc",
          "Ti",
          "V",
          "Cr",
          "Mn",
          "Fe",
          "Co",
          "Ni",
          "Cu",
          "Zn",
          "Ga",
          "Ge",
          "As",
          "Se",
          "Br",
          "Rb",
          "Sr",
          "Y",
          "Zr",
          "Nb",
          "Mo",
          "Tc",
          "Ru",
          "Rh",
          "Pd",
          "Ag",
          "Cd",
          "In",
          "Sn",
          "Sb",
          "Te",
          "I",
          "Cs",
          "Ba",
          "Hf",
          "Ta",
          "W",
          "Re",
          "Os",
          "Ir",
          "Pt",
          "Au",
          "Hg",
          "Tl",
          "Pb",
          "Bi",
          "Po",
          "At",
          "Fr",
          "Ra",
          "Ac",
          "Th",
          "Pa",
          "U"
        ]
      },
      "b": {
        "title": "Second element",
        "description": "The second atom of the bond.",
        "type": "string",
        "enum": [
          "H",
          "Li",
          "Be",
          "B",
          "C",
          "N",
          "O",
          "F",
          "Na",
          "Mg",
          "Al",
          "Si",
          "P",
          "S",
          "Cl",
          "K",
          "Ca",
          "Sc",
          "Ti",
          "V",
          "Cr",
          "Mn",
          "Fe",
          "Co",
          "Ni",
          "Cu",
          "Zn",
          "Ga",
          "Ge",
          "As",
          "Se",
          "Br",
          "Rb",
          "Sr",
          "Y",
          "Zr",
          "Nb",
          "Mo",
          "Tc",
          "Ru",
          "Rh",
          "Pd",
          "Ag",
          "Cd",
          "In",
          "Sn",
          "Sb",
          "Te",
          "I",
          "Cs",
          "Ba",
          "Hf",
          "Ta",
          "W",
          "Re",
          "Os",
          "Ir",
          "Pt",
          "Au",
          "Hg",
          "Tl",
          "Pb",
          "Bi",
          "Po",
          "At",
          "Fr",
          "Ra",
          "Ac",
          "Th",
          "Pa",
          "U"
        ]
      }
    }
  },
  "outputs": {
    "result": {
      "label": "Electronegativity difference",
      "description": "ΔEN with the bond type it suggests.",
      "format": "text"
    },
    "difference": {
      "label": "ΔEN",
      "description": "The absolute difference of the two Pauling electronegativities.",
      "format": "number"
    },
    "bond": {
      "label": "Bond type (ΔEN guide)",
      "description": "Pure covalent below 0.4, polar covalent from 0.4 to 1.8, ionic above 1.8: a rough guide.",
      "format": "text"
    },
    "enA": {
      "label": "First element’s EN",
      "description": "The first element’s Pauling value.",
      "format": "number"
    },
    "enB": {
      "label": "Second element’s EN",
      "description": "The second element’s Pauling value.",
      "format": "number"
    },
    "polarity": {
      "label": "Partial charges",
      "description": "Which atom pulls the shared electrons and takes the partial negative charge (δ−).",
      "format": "text"
    },
    "pair": {
      "label": "Bond",
      "description": "The two elements with their values.",
      "format": "text"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "a": "C",
      "b": "O"
    },
    "outputs": {
      "result": "ΔEN = 1.0: polar covalent",
      "difference": 1,
      "bond": "polar covalent",
      "enA": 2.5,
      "enB": 3.5,
      "polarity": "O pulls the shared electrons: Cδ+ and Oδ−",
      "pair": "C (2.5) and O (3.5)"
    },
    "text": "The electronegativity difference between C (2.5) and O (3.5) is 1.0: polar covalent."
  },
  "examples": [
    {
      "given": {
        "a": "C",
        "b": "O"
      },
      "expect": {
        "difference": 1,
        "bond": "polar covalent",
        "polarity": "O pulls the shared electrons: Cδ+ and Oδ−"
      },
      "source": "OpenStax, Chemistry 2e, §7.2 Covalent Bonding (Figure 7.6 Pauling electronegativities; Figure 7.8 ΔEN guide), https://openstax.org/books/chemistry-2e/pages/7-2-covalent-bonding, Example 7.3 Electronegativity and Bond Polarity: C–O, ΔEN = 1.0, Cδ+–Oδ−"
    },
    {
      "given": {
        "a": "C",
        "b": "H"
      },
      "expect": {
        "difference": 0.4,
        "bond": "polar covalent",
        "polarity": "C pulls the shared electrons: Hδ+ and Cδ−"
      },
      "source": "OpenStax, Chemistry 2e, §7.2 Covalent Bonding (Figure 7.6 Pauling electronegativities; Figure 7.8 ΔEN guide), https://openstax.org/books/chemistry-2e/pages/7-2-covalent-bonding, Example 7.3: C–H, ΔEN = 0.4, Cδ−–Hδ+"
    },
    {
      "given": {
        "a": "O",
        "b": "H"
      },
      "expect": {
        "difference": 1.4
      },
      "source": "OpenStax, Chemistry 2e, §7.2 Covalent Bonding (Figure 7.6 Pauling electronegativities; Figure 7.8 ΔEN guide), https://openstax.org/books/chemistry-2e/pages/7-2-covalent-bonding, Example 7.3: O–H, ΔEN = 1.4"
    },
    {
      "given": {
        "a": "Na",
        "b": "Cl"
      },
      "expect": {
        "difference": 2.1,
        "bond": "ionic"
      },
      "source": "OpenStax, Chemistry 2e, §7.2 Covalent Bonding (Figure 7.6 Pauling electronegativities; Figure 7.8 ΔEN guide), https://openstax.org/books/chemistry-2e/pages/7-2-covalent-bonding, Electronegativity versus Bond Type: Na–Cl, 2.1 (ionic)"
    },
    {
      "given": {
        "a": "Si",
        "b": "O"
      },
      "expect": {
        "difference": 1.7,
        "bond": "polar covalent"
      },
      "source": "OpenStax, Chemistry 2e, §7.2 Covalent Bonding (Figure 7.6 Pauling electronegativities; Figure 7.8 ΔEN guide), https://openstax.org/books/chemistry-2e/pages/7-2-covalent-bonding, Check Your Learning after Example 7.3: Si–O, ΔEN = 1.7"
    },
    {
      "given": {
        "a": "C",
        "b": "C"
      },
      "expect": {
        "difference": 0,
        "bond": "pure covalent (nonpolar)"
      },
      "source": "OpenStax, Chemistry 2e, §7.2 Covalent Bonding (Figure 7.6 Pauling electronegativities; Figure 7.8 ΔEN guide), https://openstax.org/books/chemistry-2e/pages/7-2-covalent-bonding, Check Your Learning after Example 7.3: C–C, ΔEN = 0.0, nonpolar"
    }
  ],
  "sources": [
    "OpenStax, Chemistry 2e, §7.2 Covalent Bonding: the definition of electronegativity, Figure 7.6 (Pauling electronegativity values, read from the figure), Figure 7.8 (ΔEN below 0.4 pure covalent, 0.4 to 1.8 polar covalent, above 1.8 ionic, a general guide with exceptions such as HF and MnI₂), Example 7.3 (C–H 0.4, C–O 1.0, O–H 1.4) and its Check Your Learning (C–C 0.0, Si–O 1.7), and H–Cl 0.9, Na–Cl 2.1. https://openstax.org/books/chemistry-2e/pages/7-2-covalent-bonding (retrieved 2026-10-19)",
    "Wikipedia, Electronegativities of the elements (data page): the revised two-decimal Pauling values (H 2.20, C 2.55, O 3.44) after Allred (1961). https://en.wikipedia.org/wiki/Electronegativities_of_the_elements_(data_page) (retrieved 2026-10-19)"
  ],
  "related": [
    "formal-charge",
    "oxidation-number",
    "bond-order",
    "valence-electrons"
  ],
  "changelog": []
}