Calcium carbonate is a chemical compound with the formula CaCO3. It is commonly found in rocks and seashells, and is used in the production of cement, paints, and dietary supplements.
| IUPAC Name | Calcium carbonate |
| Molecular Formula | CaCO3 |
| CAS Number | 471-34-1 |
| Synonyms | Limestone, chalk, calcite, aragonite, marble, precipitated calcium carbonate, carbonic acid calcium salt (1:1) |
| InChI | InChI=1S/CH2O3.Ca/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2 |
CaCO3 Molar Mass
The molar mass of calcium carbonate is 100.09 g/mol. This means that one mole of calcium carbonate contains 100.09 grams of the compound. The molar mass is important in stoichiometric calculations because it allows for the conversion of moles to grams or vice versa.
Calcium Carbonate Formula
The chemical formula of calcium carbonate is CaCO₃. This means that each molecule of calcium carbonate contains one calcium atom, one carbon atom, and three oxygen atoms. The formula is important in determining the amount of calcium carbonate needed for a specific application and in understanding its chemical properties.
Calcium Carbonate Boiling Point
Calcium carbonate does not have a boiling point because it decomposes before it can reach its boiling point. At atmospheric pressure, calcium carbonate decomposes into calcium oxide and carbon dioxide at temperatures above 825°C. Therefore, calcium carbonate is commonly used in high-temperature applications, such as in the production of cement.
Calcium Carbonate Melting Point
The melting point of calcium carbonate is 1,339°C. At this temperature, calcium carbonate undergoes thermal decomposition to form calcium oxide and carbon dioxide. The melting point is important in understanding the behavior of calcium carbonate at high temperatures.
Calcium Carbonate Density g/ml
The density of calcium carbonate is 2.71 g/cm³. This means that calcium carbonate is denser than water and will sink when placed in water. The density is important in understanding the physical properties of calcium carbonate and in determining its uses in various applications.
Calcium Carbonate Molecular Weight
The molecular weight of calcium carbonate is 100.09 g/mol. This means that the compound is composed of one calcium atom, one carbon atom, and three oxygen atoms. The molecular weight is important in determining the amount of calcium carbonate needed for a specific application and in understanding its chemical properties.
Calcium Carbonate Structure
The structure of calcium carbonate is crystalline and composed of calcium ions (Ca²⁺) and carbonate ions (CO₃²⁻). The calcium ions are located in the center of the structure and are surrounded by six carbonate ions. The carbonate ions are arranged in a trigonal planar shape, with each oxygen atom connected to the carbon atom by a double bond. The structure is important in understanding the behavior of calcium carbonate in various applications, such as in the formation of seashells and coral reefs.
| Appearance | White powder or colorless crystal |
| Specific Gravity | 2.71 |
| Color | White |
| Odor | Odorless |
| Molar Mass | 100.09 g/mol |
| Density | 2.71 g/cm³ |
| Melting Point | 1,339°C |
| Boiling Point | Decomposes before boiling |
| Flash Point | Not applicable |
| Water Solubility | 0.0013 g/100 mL (25°C) |
| Solubility | Insoluble in water and most organic solvents |
| Vapor Pressure | Negligible |
| Vapor Density | Not applicable |
| pKa | 9.00 (first); 11.8 (second) |
| pH | 9.3 – 9.7 (0.1 M aqueous solution) |
Calcium Carbonate Safety and Hazards
Calcium carbonate is generally considered to be safe for humans and the environment when used as directed. However, inhalation of calcium carbonate dust can cause irritation to the respiratory tract, eyes, and skin. Long-term exposure to high concentrations of calcium carbonate dust may cause lung damage. Calcium carbonate can also react with strong acids to produce carbon dioxide gas, which can cause a fire or explosion hazard in some situations. It is important to follow proper safety procedures when handling calcium carbonate, such as wearing protective equipment and ensuring adequate ventilation.
| Hazard Symbols | Not applicable |
| Safety Description | Avoid inhalation of dust. Wear protective equipment. |
| UN IDs | Not regulated |
| HS Code | 2836.50.00 |
| Hazard Class | Not regulated |
| Packing Group | Not applicable |
| Toxicity | Low toxicity to humans and the environment |
Calcium Carbonate Synthesis Methods
Various methods can synthesize calcium carbonate (CaCo3), including precipitation, carbonation, and sol-gel methods.
The precipitation method involves mixing calcium hydroxide with a soluble carbonate salt, such as sodium carbonate, under controlled conditions to form CaCo3 precipitate. To obtain the final product, one must filter and dry the precipitate.
The carbonation method involves reacting calcium oxide with carbon dioxide gas under high pressure and temperature to produce CaCo3. One must carry out the reaction in a closed system to prevent the escape of carbon dioxide gas. Afterward, one should separate any unreacted calcium oxide or carbon dioxide from the resulting CaCo3 and purify it.
The sol-gel method involves the hydrolysis and condensation of a calcium-containing precursor, such as calcium alkoxide or calcium nitrate, in the presence of a solvent and a catalyst. To produce CaCo3, one must dry and calcine the resulting gel.
The method to synthesize CaCo3 involves utilizing biomineralization, where living organisms such as coral or oyster shells generate CaCo3 crystals. Operators collect these crystals and process them to obtain the final product.
Each method has its own advantages and disadvantages, and the choice of method depends on factors such as cost, purity, and desired particle size of the final product.
Calcium Carbonate Uses
Calcium carbonate has numerous uses in various industries, due to its properties such as low toxicity, high purity, and availability at low cost. Some common uses of calcium carbonate are:
- Construction: Used as a building material in the form of limestone, marble, and chalk. Used as a filler to improve the strength and durability of cement, mortar, and concrete.
- Pharmaceuticals: Used in the production of antacids and calcium supplements. Used as an excipient when formulating tablets and capsules.
- Food and Beverage: Used as a food additive to provide calcium fortification and as a pH adjuster in beverages.
- Paper and Pulp: Used as a filler and coating agent in the production of paper and paperboard, to improve printability and whiteness.
- Plastics: Used as a filler and reinforcing agent in plastic products, to improve their mechanical properties and reduce cost.
- Paints and Coatings: Used as a pigment and filler in paints and coatings, to improve their opacity and coverage.
- Agriculture: Used as a soil conditioner to improve soil quality and crop growth.
- Water Treatment: Used to neutralize acidic water and to remove impurities from water.
These are some of the most common uses of calcium carbonate, but there are many other applications in various industries.
Questions:
Q: Is calcium carbonate soluble in water?
A: Calcium carbonate has low solubility in water, with a solubility of approximately 0.0013 g/100 mL at 25°C.
Q: What is calcium carbonate?
A: Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks, shells of marine organisms, and in various mineral deposits.
Q: Where can calcium carbonate be found?
A: Calcium carbonate can be found in various natural sources such as limestone, chalk, and marble. It is also found in the shells of marine organisms such as oysters, clams, and coral.
Q: Is calcium carbonate ionic or covalent?
A: Calcium carbonate is an ionic compound, consisting of a calcium cation (Ca2+) and a carbonate anion (CO32-).
Q: Calcium carbonate is a type of hydrogenous sediment that can be buried and hardened into _____.
A: Calcium carbonate is a type of hydrogenous sediment that can be buried and hardened into limestone.
Q: The layered structures made of calcium carbonate by Precambrian cyanobacteria are called _____.
A: The layered structures made of calcium carbonate by Precambrian cyanobacteria are called stromatolites.