Chromium is a very hard gray solid with a metallic luster. (NTP, 1992) Chromium is a transition element with the chemical symbol Cr and atomic number 24 that belongs to Group 6 of the periodic table. It is used in various chemical, industrial and manufacturing applications such as wood preservation and metallurgy.
What are the chemical properties of chromium?
- Atomic number: 24
- Atomic weight: 51.996
- Melting point: 1,890 °C (3,434 °F)
- Boiling point: 2,482 °C (4,500 °F)
- Specific gravity 7.20 (28 °C)
- Oxidation states: +2, +3, +6
What are the characteristics of physical properties?
Physical properties are the characteristics of a substance that are called "observable." They are measurable, collectible information about substances that scientists can gather, record, and compare to previous recordings. There are two kinds of physical properties: intensive properties and extensive properties.
What is the formula for chromium?
Chromium (VI) phosphate has the chemical formula Cr (PO4)2 because it contains one chromium ion bonded to two phosphate ions. The phosphate ions each have a charge of negative 3, while the chromium ion has a charge of positive 6. For chromium and other transition metals, a Roman numeral refers to the charge of the metal ion.
What is the process of chromium?
chromium processing, preparation of the ore for use in various products. Chromium (Cr) is a brilliant, hard, refractory metal that melts at 1,857 °C (3,375 °F) and boils at 2,672 °C (4,842 °F). In the pure state it is resistant to ordinary corrosion, resulting in its application as an electroplated
What are the physical and chemical properties of chromium?
Table 4-2Physical and Chemical Properties of Chromium and CompoundsPropertyChromiumChromium(III) chloridePhysical stateSolidSolidMelting point1,90±10 °C≈1,150 °CBoiling point2,642 °CDecomposes at 1,300 °CDensity at 20 °C7.14 (28 °C)a2.87 (25 °C)a19 more rows
Is chromium a physical or chemical property?
chemical elementChromium is a chemical element with Cr as its symbol. It belongs to group 6, periodic number 4 of the periodic table. Its atomic number is 24.
Is chromium metal reactive?
At room temperature, Chromium metal does not react with water or air. It will react with the halogens fluorine, chlorine, bromine, and iodine to form colorful compounds. It can also dissolve with hydrochloric acid or sulphuric acid to create solutions containing the Cr(II) ion with H2.
What are the chemical properties of chromium oxide?
Chromium(III) Oxide Properties (Theoretical)Compound FormulaCr2O3AppearanceGreen powder or crystalsMelting Point2435 °C (4415 °F)Boiling Point4000 °C (7232 °F)Density5.22 g/cm34 more rows
What are 3 physical properties of chromium?
Chromium Basic Facts Chromium Properties: Chromium has a melting point of 1857+/-20°C, a boiling point of 2672°C, a specific gravity of 7.18 to 7.20 (20°C), with valences usually 2, 3, or 6. The metal is a lustrous steel-gray color which takes a high polish. It is hard and resistant to corrosion.
Is chromium water soluble?
Solubility of chromium and chromium compounds Chromium (III) compounds are water insoluble because these are largely bound to floating particles in water. Chromium (III) oxide and chromium (III) hydroxide are the only water soluble compounds.
What color does chromium burn?
Silver-whiteCommon elementsSymbolNameColorCrChromiumSilver-whiteCsCaesiumBlue-violetCu(I)Copper(I)Bluish-greenCu(II)Copper(II) (non-halide)Green45 more rows
Why is chromium not magnetic?
(Below 38 degrees Celsius, at least.) The explanation I've always gotten is, roughly, 'well, in chromium each atom pairs with another atom, cancelling out the magnetic field' (i.e. antiferromagnetism) - but this leaves a lot to be desired.
Is chromium easy to break?
Physical properties Chromium is a hard, steel-gray, shiny, metal that breaks easily. It has a melting point of 1,900°C (3,450°F) and a boiling point of 2,642°C (4,788°F).
Is chromium is a metal?
A hard, silvery metal with a blue tinge. Chromium is used to harden steel, to manufacture stainless steel (named as it won't rust) and to produce several alloys. Chromium plating can be used to give a polished mirror finish to steel.
Is chromium a metal or nonmetal?
metalchromium (Cr), chemical element of Group 6 (VIb) of the periodic table, a hard steel-gray metal that takes a high polish and is used in alloys to increase strength and corrosion resistance.
What is chromium made of?
Naturally occurring chromium is composed of three stable isotopes; 52Cr, 53Cr and 54Cr, with 52Cr being the most abundant (83.789% natural abundance).
What kind of element is chromium?
metalchromium (Cr), chemical element of Group 6 (VIb) of the periodic table, a hard steel-gray metal that takes a high polish and is used in alloys to increase strength and corrosion resistance.
Is chromium is a metal?
A hard, silvery metal with a blue tinge. Chromium is used to harden steel, to manufacture stainless steel (named as it won't rust) and to produce several alloys. Chromium plating can be used to give a polished mirror finish to steel.
Is chromium metal magnetic?
Chromium has unique magnetic properties - chromium is the only elemental solid that shows antiferromagnetic ordering at room temperature and below. Above 38 °C, its magnetic ordering becomes paramagnetic.
What are the chemical properties of manganese?
Manganese is a pinkinsh-gray, chemically active element. It is a hard metal and is very brittle. It is hard to melt, but easily oxidized. Manganese is reactive when pure, and as a powder it will burn in oxygen, it reacts with water (it rusts like iron) and dissolves in dilute acids.
What are the characteristics of chromium?
Chemical Characteristics. Chromium form variety of compounds and exists in many oxidation states, including +3, +6, +1. +4 and +5. The predominant and most stable oxidation state of chromium is +3 [5]. Large number of chromium [III] compounds are present, such as compound of chromium with sulfuric and hydrochloric acid.
What are the dangers of chromium?
Large amounts of chromium compounds are being released into environment by various industries, tanneries (paints, dyes, leather manufacturing), and pose threat of contamination of soil and water.
How many isotopes of chromium are there?
Natural chromium has four isotopes: chromium-50, chromium-52, chromium-53, chromium-54. There are twenty-one other isotopes of chromium. Chromium-53 is the most abundant among all isotopes. Several isotopes of chromium are used for medical purposes.
What is the best metal to use for car coating?
Chromium. Chromium is a transition metal that was discovered by Gottlob Lehmann in 1766. It has a shiny surface that is resistant to corrosion and this quality makes its ideal for manufacturing and coating of wide range of material, including cars and bikes.
What is the source of chromium?
Chromite is the principal source of chromium that is used in pigments, worldwide. Chromium is released in the environment by erosion of rocks that contain chromium. Volcanic activities also play important role in the distribution of chromium.
What is chromium plating used for?
Chromium plating is used for bikes and cars. Chromium has been widely used in the manufacturing of dyes, pigments and paints due to its unique and wide range of colors. Chromium oxides are used for dying glass and ceramics. It imparts natural green color and is also used by armed forces to paint their tanks and vehicles to imitate infrared ...
What is the widest use of chromium?
The widest usage of chromium is in the making of metal alloys. Chromium can impart strength corrosion resistance and shine to various metals and is widely used in the manufacturing of steel.
What is the color of chromium?
Vaughlin in 1797. Chromium. Chromium is a lustrous, brittle, hard metal. Its colour is silver-gray and it can be highly polished. It does not tarnish in air, when heated it borns and forms the green chromic oxide. Chromium is unstable in oxygen, it immediately produces a thin oxide layer that is impermeable to oxygen and protects the metal below.
How does chromium affect the environment?
Chromium enters the air, water and soil in the chromium(III) and chromium(VI) form through natural processes and human activities.
How does acidification affect chromium uptake?
Crops contain systems that arrange the chromium-uptake to be low enough not to cause any harm. But when the amount of chromium in the soil rises, this can still lead to higher concentrations in crops. Acidification of soil can also influence chromium uptake by crops. Plants usually absorb only chromium(III).
What are the effects of chromium hexavalent?
Adverse effects of the hexavalent form on the skin may include ulcerations, dermatitis, and allergic skin reactions. Inhalation of hexavalent chromium compounds can result in ulceration and perforation of the mucous membranes of the nasal septum, irritation of the pharynx and larynx, asthmatic bronchitis, bronchospasms and edema.
What are the main human activities that increase the concentrations of chromium III?
The main human activities that increase the concentrations of chromium (III) are steal, leather and textile manufacturing . The main human activities that increase chromium(VI) concentrations are chemical, leather and textile manufacturing, electro painting and other chromium(VI) applications in the industry.
How can you get chromium?
People can be exposed to chromium through breathing, eating or drinking and through skin contact with chromium or chromium compounds. The level of chromium in air and water is generally low. In drinking water the level of chromium is usually low as well, but contaminated well water may contain the dangerous chromium(IV); hexavalent chromium. For most people eating food that contains chromium(III) is the main route of chromium uptake, as chromium(III) occurs naturally in many vegetables, fruits, meats, yeasts and grains. Various ways of food preparation and storage may alter the chromium contents of food. When food in stores in steel tanks or cans chromium concentrations may rise.
What is the purpose of chlorium?
Chromium is used in metallurgy to impart corrosion resistance and a shiny finish; as dyes and paints, its salts colour glass an emerald green and it is used to produce synthetic rubies; as a catalyst in dyeing and in the tanning of leather; to make molds for the firing of bricks.
What is the electronegativity of chromium?
The electronegativity of Chromium is: χ = 1.66
How many protons does chromium have?
Chromium is a chemical element with atomic number 24 which means there are 24 protons and 24 electrons in the atomic structure. The chemical symbol for Chromium is Cr.
How is atomic weight determined?
Therefore it is determined by the mass number (number of protons and neutrons).
How are the chemical properties of a solid, liquid, gas, and plasma determined?
The chemical properties of the atom are determined by the number of protons, in fact, by number and arrangement of electrons. The configuration of these electrons follows from the principles of quantum mechanics. The number of electrons in each element’s electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior. In the periodic table, the elements are listed in order of increasing atomic number Z.
What is the atomic number density?
Atomic Number Density. The atomic number density (N; atoms/cm 3 ), which is associated with atomic radii, is the number of atoms of a given type per unit volume (V; cm 3) of the material. The atomic number density (N; atoms/cm 3) of a pure material having atomic or molecular weight (M; grams/mol) and the material density (⍴; gram/cm 3) is easily computed from the following equation using Avogadro’s number ( NA = 6.022×1023 atoms or molecules per mole):
How does density affect the density of a material?
Most materials expand when their temperatures increase. Rising temperatures make the liquid expand in a liquid-in-tube thermometer and bend bimetallic strips. As a result of this expansion, the density of most materials decreases. This effect is caused by a decrease in the atomic number density. This dependence is usually expressed by the coefficient of linear or volume expansion.
What is the density of a substance?
Since the density (ρ) of a substance is the total mass (m) of that substance divided by the total volume (V) occupied by that substance, it is obvious, the density of a substance strongly depends on its atomic mass and also on the atomic number density (N; atoms/cm 3 ),
A. Hardness Comparison
In the electroplating industry, the two most commonly used measurements of hardness are Vickers (HV) and Rockwell C (HRc). Both these hardness tests measure the indentation hardness of a part or thin section of material.
B. Coefficient of Friction of Hard Chrome
Coefficient of Friction (CoF) is defined as the ratio used to quantify the friction force between two objects in relation to the normal force that is keeping them together. This is relevant for engineers that have multiple parts that come in contact with each other. Hard chrome has a very low coefficient of friction.
C. Coefficient of Linear Thermal Expansion (CTE)
Coefficient of Linear Thermal Expansion (CTE) is defined as the fractional increase in length per unit rise in temperature. When subjected to heat, materials will inevitably expand, and over small temperature ranges, the thermal expansion of uniform linear objects is proportional to temperature change.
D. Corrosion Resistance
Electroplated chromium has good resistance to a variety of corrosive environments. It offers protection against chemical sources including Citric Acids, Nitric Acids, Sodium Chloride and Copper Sulphate. The following table shows several corrodents and how resistant chromium is to them. R – usually completely resistant
