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💍inorganic chemistry ii review

Metal chromates

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Metal chromates are inorganic compounds containing the chromate anion, CrO₄²⁻, combined with metal cations. These compounds are notable for their vibrant colors and are often used as pigments and dyes in various applications, such as coatings and plastics, due to their stability and resistance to fading.

5 Must Know Facts For Your Next Test

  1. Metal chromates are highly colored, with some examples including lead chromate (yellow), barium chromate (green), and zinc chromate (yellow-green), making them popular choices for pigments.
  2. These compounds can be toxic and pose environmental hazards due to the chromium they contain, especially in their hexavalent form, leading to regulations on their use in many applications.
  3. Metal chromates exhibit good thermal stability and excellent resistance to light and weathering, which makes them suitable for outdoor applications such as industrial coatings.
  4. They can react with other chemicals to produce complex hues and shades, allowing artists and manufacturers to create a wide range of color effects.
  5. In addition to their use in pigments, metal chromates have applications in corrosion resistance treatments for metals and as analytical reagents in chemical analysis.

Review Questions

  • How do metal chromates contribute to the color properties of pigments and dyes?
    • Metal chromates contribute to the color properties of pigments and dyes primarily due to the specific electronic transitions of the chromium ion within the chromate anion. The different oxidation states of chromium can lead to a variety of colors; for example, CrO₄²⁻ gives yellow or green hues depending on the metal cation it is combined with. This versatility allows manufacturers to create a wide range of vibrant pigments suitable for various applications.
  • Discuss the environmental and health concerns associated with the use of metal chromates in pigments.
    • The use of metal chromates in pigments raises significant environmental and health concerns primarily due to their toxicity, particularly in the hexavalent state (Cr(VI)). Hexavalent chromium is classified as a carcinogen and can pose serious health risks if inhaled or ingested. Regulatory bodies have imposed strict guidelines on the use of these compounds in many industries, leading to research into safer alternatives while still maintaining color quality.
  • Evaluate the impact of regulatory measures on the production and usage of metal chromates in the pigment industry.
    • Regulatory measures have profoundly impacted the production and usage of metal chromates in the pigment industry by enforcing stricter controls over their use due to health and environmental risks. These regulations have pushed manufacturers to seek alternative pigments that are safer yet still meet quality standards for color vibrancy and stability. As a result, innovation has led to the development of new synthetic dyes and eco-friendly options, reshaping how industries approach coloration while adhering to safety guidelines.
Metal chromates Definition - Inorganic Chemistry II Key Term | Fiveable