1/15/2024 0 Comments Cl charge in kclo![]() Theoretical predictions were successfully verified by experimental synthesis of two KCl 3 polymorphs in a laser-heated diamond anvil cell (DAC). In each of these calculations, all possible chemical compositions were allowed with up to 16 atoms in the unit cell and calculations were performed at pressures of 1 atm, 10 GPa, 35 GPa, 50 GPa, 100 GPa, 150 GPa, 200 GPa, 250 GPa and 300 GPa. Here we study the K-Cl system using the quantum-mechanical variable-composition evolutionary structure prediction methodology USPEX 16, 17, 18, 19, searching for stable compounds and their corresponding crystal structures (see Methods). Yet, as we find, the K-Cl system has a much richer chemistry than Na-Cl. The same transition occurs in NaCl, but at a much higher pressure of 30 GPa 14, 15, reflecting the general tendency for phase transitions to occur at lower pressures for compounds of heavier elements. Two crystal structures are known for KCl: the rocksalt-type (B1) structure and cesium chloride-type (B2) structure, the latter becoming stable at ~2 GPa. The only known potassium chloride, KCl, has been extensively studied under pressure, both experimentally 8, 9, 10 and using ab initio simulations 11, 12, 13. Here we study K-Cl, a system closely related to Na-Cl and find even richer chemistry and new phenomena. 2 have been synthesized and theoretically verified 7, revealing dramatic changes of chemistry under pressure. These systems were subsequently explored experimentally: while so far the predictions have not been verified for Li-H 5, for Na-Cl and Mg-O, the predicted compounds (NaCl 3, Na 3Cl and MgO 2) have been confirmed experimentally 4, 6, while more stable NaH x compounds than originally predicted by Zurek et al. Recent ab initio calculations predicted the formation of unexpected novel high-pressure compounds in several simple systems, such as Li (Na)-H 1, 2 Mg-O 3 and Na-Cl 4. Upon unloading to 10 GPa, -KCl 3 transforms to a yet unknown structure before final decomposition to KCl and Cl 2 at near-ambient conditions. These phases were identified using in situ synchrotron X-ray diffraction and Raman spectroscopy. We have synthesized cubic -KCl 3 at 40–70 GPa and trigonal -KCl 3 at 20–40 GPa in a laser-heated diamond anvil cell (DAC) at temperature exceeding 2000 K from KCl and Cl 2. Of particular interest are 2D-metallic homologs K n+1Cl n, the presence of positively charged Cl atoms in KCl 7 and the predicted stability of KCl 3 already at nearly ambient pressures at zero Kelvin. However, our quantum-mechanical variable-composition evolutionary simulations predict an extremely complex phase diagram, with new thermodynamically stable compounds K 3Cl, K 2Cl, K 3Cl 2, K 4Cl 3, K 5Cl 4, K 3Cl 5, KCl 3 and KCl 7. The charge balance rule, assigning classical charges of “+1” to K and “−1” to Cl, predicts that no compounds other than KCl are possible. Mass of O = (atomic mass of O) x (subscript of O) = (15.9994 g) x (3) = 47.K-Cl is a simple system displaying all four main types of bonding, as it contains (i) metallic potassium, (ii) elemental chlorine made of covalently bonded Cl 2 molecules held together by van der Waals forces and (iii) an archetypal ionic compound KCl. ![]() Mass of Cl = (atomic mass of Cl) x (subscript of Cl) = (35.453 g) x (1) = 35.453 g ![]() Note: the subscript represents how many moles of that element are present in the compound. ![]() % by mass element = x 100ġ) Using the periodic table, we can find the atomic mass for each element:Ģ) If we are assuming we have 1 mol of KClO 3, we can calculate the mass of each element in 1 mol of compound by multiplying its atomic mass by the subscript next to that element. The general equation for calculating the percent by mass of any element in a compound is:
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