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BeH 2 is usually formed as an amorphous white solid, but a hexagonal crystalline form with a higher density (~0.78 g/cm 3) was reported, [7] prepared by heating amorphous BeH 2 under pressure, with 0.5-2.5% LiH as a catalyst. Subunit of structure of BeH 2. Each Be is tetrahedral and each H is doubly bridging. [8]
Matter organizes into various phases or states of matter depending on its constituents and external factors like pressure and temperature.Except at extreme temperatures and pressures, atoms form the three classical states of matter: solid, liquid and gas.
The term phase is sometimes used as a synonym for state of matter, but it is possible for a single compound to form different phases that are in the same state of matter. For example, ice is the solid state of water, but there are multiple phases of ice with different crystal structures , which are formed at different pressures and temperatures.
The other form resembles zinc iodide with interconnected adamantane-like cages. [4] In contrast, BeF 2 is a 3-dimensional polymer, with a structure akin to that of quartz. In the gas phase, BeCl 2 exists both as a linear monomer and a bridged dimer with two bridging chlorine atoms where the beryllium atom is 3-coordinate. [5]
Beryllium fluoride has distinctive optical properties. In the form of fluoroberyllate glass, it has the lowest refractive index for a solid at room temperature of 1.275. Its dispersive power is the lowest for a solid at 0.0093, and the nonlinear coefficient is also the lowest at 2 × 10 −14.
The propensity for any two substances to form a solid solution is a complicated matter involving the chemical, crystallographic, and quantum properties of the substances in question. Substitutional solid solutions, in accordance with the Hume-Rothery rules, may form if the solute and solvent have: Similar atomic radii (15% or less difference)
A polar molecule has a net dipole as a result of the opposing charges (i.e. having partial positive and partial negative charges) from polar bonds arranged asymmetrically. Water (H 2 O) is an example of a polar molecule since it has a slight positive charge on one side and a slight negative charge on the other. The dipoles do not cancel out ...
A solid with extensive hydrogen bonding will be considered a molecular solid, yet strong hydrogen bonds can have a significant degree of covalent character. As noted above, covalent and ionic bonds form a continuum between shared and transferred electrons; covalent and weak bonds form a continuum between shared and unshared electrons.