What is the difference between van der Waals radius, metal radius, covalent radius

The difference in the formation of 3 radii forces or bonds is van der Waals force, metallic bond, covalent bond. Look

The van der Waals radius refers to the fact that in a molecular crystal, the molecules are bound together by a van der Waals force (a force of attraction that exists between molecules), such as half the distance between two adjacent nuclei of a noble gas.

Metal Radius: In a metal lattice, half of the distance between the nuclei of adjacent metals is called the metal radius of the atom r=1 2L

It can be obtained from the crystal structure and unit cell parameters of the metal. For example, the unit cell of copper metal is a cubic centric unit cell, and the unit cell parameter a= is known, then the radius r of the Cu atom is: r=a (2)=. The radius of the metal is related to the coordination number, and the coordination number is high, and the radius is large.

The covalent radius (rcov) is a measure of the contribution of the size of the atoms that make up the covalent bond to the length of the covalent bond, and is commonly used in picometers (pm) or angstroms ( ) which is converted to 1 = 100 pm. The American physicist Linus Pauling defines the covalent radius of an atom as half the distance between two identical nuclei bound by a covalent single bond, for example: in a hydrogen elemental molecule r(h h,) = pm, so rcov(h) = pm.

In practice, the covalent radius is a statistical average obtained by combining a variety of experimental measurements. For covalent bonds formed by different atoms, theoretically the length of the covalent bonds can be expressed as the sum of the covalent radii of the constituent atoms, i.e., r(ab) = r(a) + r(b).

Obviously, this relationship is not absolute, because the actual size of an atom is related to the chemical environment in which it is placed. For a polar covalent bond, its ionic composition is also large, and the bond length is usually less than the sum of the covalent radii of the constituent atoms. At the same time, the bond length of a multi-bond is shorter than that of the corresponding single-bond, and in general, the radius of a double bond is 86% of the radius of a single bond, and the radius of a triple bond is 78% of the radius of a single bond.

The Van der Waals radius of an atom refers to the Van der Waals force (a kind of attraction that exists between molecules) in a molecular crystal, and in the case of noble gases, half of the distance between two adjacent nuclei is the Van der Waals radius.

Chinese name: Van der Waals radius.

Attributes: Non-metallic elements have a radius.

Also known as: Fan's radius.

Real column: Half of the distance between two adjacent nuclei of the molecular crystal of a noble gas.

Fan's (van der Waals) radius Non-metallic elements have a kind of radius, called Fan's radius For example, in a CDCL2 crystal, the nuclear spacing between Cl and Cl in different "molecules" (actually layered macromolecules) is measured as: d(Cl-Cl) = take half of its value and set it as the Van's radius of the chlorine atom, i.e.: r Fan = 1 2 ( For non-metallic elements, there is always a laugh Sun R Fan "r altogether), this relationship can be clearly seen from the above diagram The figure shows 2 Cl2s, in the same Cl2, Half of the spacing between the first two Cl nuclei is the covalent radius r; Between different 2 Cl2s, half of the nucleus spacing of 2 Cl is the Fan's radius r Fan Obviously, r Fan >> r In general, for metallic elements, there are only covalent radii and metal radius; Non-metallic elements (except noble gases) have covalent radii and Zeqing Fan's radius; The only noble gas element is the Fan's radius The atomic radius in high school textbooks is all covalent radius, so the radius of the noble gas element is not comparable with other elements of the same period

Van der Waals Forces: Universally found between solid, liquid, and gaseous particles. So even if there are different kinds of molecules, they will be produced. There is also this force between the complexes molecules. Whereas, there is a coordination bond connection between the ligand and the central ion, which is a chemical bond, not van der Waals force.

The Van der Waals radius of an atom refers to the fact that when two adjacent but unbonded atoms in a molecule are close to a certain distance, it is conceivable that the repulsive force of the atom itself can be in the range of a rigid sphere, and the radius of this sphere is called the Van der Waals radius.

The first question, of course, is that the van der Waals radius of h is not the same as the radius of h, because h also has a covalent radius and an ionic radius, which is the radius of the covalent bond of h (half the length of the bond in the hydrogen molecule in hydrogen), and the radius of h+ or h-. The van der Waals radius can be thought of as the distance deficit between hydrogen molecules.

The second question can be considered in this way.

Radius refers to the radius of the atom, and we can't measure the radius of the atom directly.

The covalent radius refers to the measured radius after the atom forms a covalent bond, such as half of the distance between two chlorine atoms in the Cl2 molecule, which is the covalent radius of the chlorine atom.

The metal radius refers to half of the distance between the two atoms measured after the metal atoms form a crystal, which is called the metal radius.

The covalent radius refers to half the length of the covalent bond that connects the same atoms, and in a metal lattice, half of the distance between the nuclei of adjacent metals is called the metal radius of the atom. The radius of the metal is related to the coordination number, which is the number of alien charged atoms closest to the positive charge (or negative charge). This requires knowing the spatial configuration of the compound.

The van der Waals radius refers to the distance between two molecules attracted by van der Waals forces; The metal radius refers to the distance between two metal atoms connected by metal bonds; The covalent radius refers to the distance between 2 atoms connected by a covalent bond.

The van der Waals radius of an atom refers to the fact that in a molecular crystal, the molecules are bound together by van der Waals force (a kind of attraction that exists between molecules), such as half of the distance between two adjacent nuclei of a noble gas

The van der Waals radius is half the distance between two adjacent nuclei between molecules.

For example, the van der Waals radius of hydrogen is half the distance between two adjacent nuclei between hydrogen molecules.