Molecular covalent

This type of argument leads us to picture a metal as an array of positive ions located at the crystal lattice sites, immersed in a sea of mobile electrons. The idea of a more or less uniform electron sea emphasizes an important difference between metallic bonding and ordinary covalent bonding. In molecular covalent bonds the electrons are localized in a way that fixes the positions of the atoms quite rigidly. We say that the bonds have directional character— the electrons tend to remain concentrated in certain regions of space. In contrast, the valence electrons in a metal are spread almost uniformly throughout the crystal, so the metallic bond does not exert the directional influence of the ordinary covalent bond. 

A normal oxide is a binary (two element) compound containing oxygen in the -2 oxidation state. BaO is an example of an ionic oxide and S02 is an example of a molecular (covalent) oxide. 

There is a wide range of molecules which use covalent bonding, and they can exhibit a wide range of physical and chemical properties. Many of these differences result from the scale of the bonding. Molecular covalent molecules... 

In molecular covalent compounds, intermolecular forces are very weak in comparison with intramolecular forces. For this reason, most covalent substances with a low molecular mass are gaseous at room temperature. Others, with higher molecular masses may be liquids or solids, though with relatively low melting and boiling points. 

Every syllable in the name of a chemical compound conveys something about that compound. From ionic and molecular (covalent) compounds to organic hydrocarbons and acids, the names matter, and you find out why in this part. 

Naming Molecular (CoValent) Compounds and Writing Their Formulas... 

Does the formula contain a metal (not hydrogen) If there s no metal, you re naming a molecular (covalent) compound, so you need to use the prefixes in Table 6-2. Be sure to change the ending of the second element to -ide. If there is a metal, then you re dealing with an ionic compound, so proceed to Question 3. 

One may however consider that the integrated operation of its individual components confers to a molecular (covalently linked) device a flavour of supramolecular nature, since its function extends over the whole device in a sort of superstructure fashion. It then would appear justified to include in the domain of supramolecular chemistry systems that bear relation to supramolecular species on functional grounds, systems whose function is of supramolecular nature although they are clearly molecular in terms of structure and bonding. A further reason for not excluding such a possibility lies in the considerable enrichment that such an open view brings to the field ... 

Self-assembly is the broader term. It can be taken to designate the evolution towards spatial confinement through spontaneous connection of a few/many components, resulting in the formation of discrete/extended entities at either the molecular, covalent or the supramolecular, non-covalent level. 

Supramolecular, non-covalent, synthesis consists in the generation of supramolecular architectures through the designed assembly of molecular components directed by the physico-chemical features of intermolecular forces like molecular, covalent, synthesis, it requires strategy, planning and control. 

The structures of the element trihalides EX3 are covered in a number of textbooks on structural inorganic chemistry (4, 5), and these will not be discussed in great detail here. It is, however, worth mentioning some of the salient structural features. In most cases, a molecular trigonal pyramidal EX3 unit consistent with VSEPR theory predictions is readily apparent in the solid-state structure, although there are usually a number of fairly short intermolecular contacts or secondary bonds present. A general description of the structures as molecularly covalent but as having a tendency toward macromolecular or polymeric networks is therefore reasonable. Only in the case of the fluorides is an ionic model appropriate. 

Molecule Basic unit for molecular (covalent) compounds. 

The name of a molecular compound reveals its composition and is important in communicating the nature of the compound. Figure 9-9 can help you determine the name of a molecular covalent compound. 

One convenient way of classifying solids is according to the dominant bonding forces between the constituents in the crystal, i.e. as molecular, covalent, ionic or metallic crystals. Hydrogen bonding may, in addition, contribute significantly to crystal stability and is often important in hydrates. 

Form ionic compounds with metals and molecular (covalent) compounds with other nonmetals... 

Knowledge of the relative values of ionization energies assists us in predicting whether an element is likely to form ionic or molecular (covalent) compounds. Elements with low ionization energies form ionic compounds by losing electrons to form cations (positively... 

Distinguish among and compare the characteristics of molecular, covalent, ionic, and metallic solids. Give two examples of each kind of solid. 

How do the physical properties of a network covalent solid and a molecular covalent solid differ Why ... 

Can you explain why network covalent compounds have much higher melting points than molecular covalent compounds ... 

Manganese silicide has the empirical formula MnSi and melts at 1280 C. It is insoluble in water but does dissolve in aqueous HF. (a) What type of compound do you expect MnSi to be metallic, molecular, covalent-network, or ionic (b) Write a likely balanced chemical equation for the reaction of MnSi with concentrated aqueous HF. 

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