What is Ion: Definition and 404 Discussions

An ion () is a particle, atom or molecule with a net electrical charge.
The charge of the electron is considered negative by convention. The negative charge of an ion is equal and opposite to charged proton(s) considered positive by convention. The net charge of an ion is non-zero due to its total number of electrons being unequal to its total number of protons.
A cation is a positively charged ion with fewer electrons than protons while an anion is negatively charged with more electrons than protons. Because of their opposite electric charges, cations and anions attract each other and readily form ionic compounds.
Ions consisting of only a single atom are termed atomic or monatomic ions, while two or more atoms form molecular ions or polyatomic ions. In the case of physical ionization in a fluid (gas or liquid), "ion pairs" are created by spontaneous molecule collisions, where each generated pair consists of a free electron and a positive ion. Ions are also created by chemical interactions, such as the dissolution of a salt in liquids, or by other means, such as passing a direct current through a conducting solution, dissolving an anode via ionization.

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  1. T

    Safer Lithium Ion Batteries - a Significant Step

    The folks at MIT have found a way to avoid the dendrites that short-circuit Li Ion batteries. This will allow getting rid of the very flammable liquid electrolyte. https://news.mit.edu/2022/controlling-dendrities-lithium-batteries-1118 Cheers, Tom
  2. D

    ESA's Dual Stage 4 Grid Ion propulsion

    I have found remarkably little information about ESA's Ion Drive in collaboration with Australia: https://en.wikipedia.org/wiki/Dual-Stage_4-Grid https://www.esa.int/gsp/ACT/doc/PRO/ACT-RPR-PRO-IAC2006-DS4G-C4.4.7.pdf Reference...
  3. D

    Is the Dual-Stage 4 Grid Ion Drive the Key to Faster Space Travel?

    My post was removed originally about a designed based on this new engine. I don't know what specific forum rule I broke, I read the entire thing. But I am posting a new threat to ask about the validity of this specific technology. I am asking because there seems to be zero media coverage of it...
  4. H

    A Determination of electron temperature in an ion source

    How to correctly determine the temperature of electrons in an ion source based on ECR? Is it possible to use the Saha equation? ##\frac{n_en_i}{n_a}=\frac{g_eg_i}{g_a}*3*10^{21} T^{3/2} e^{-J/T}## Using the search, I found the McWhirter criterion for the applicability of the formula above: ##n_e...
  5. N

    Acceleration of Uranium 238 ion through a potential difference

    I don't understand why the Uranium 238 ions are accelerated I think ##\Delta V = -2000 V## to accelerate since the ion would be accelerated by more postive charges so ## V_i > V_f ##
  6. gggnano

    I may need 29 megawatts just to lift 180 kgs with ion thruster...

    So after reading a great paper from Utah university (or so) they include the following equation which should apply at least to some type of electric thrusters: P(power) = T(thrust in N)*S(specific impulse in secs)*G/(2*Efficiency) x=(1800*1000*9.8)/(2*0.3) x = 29,000,000 watts needed to lift a...
  7. M

    A The Effect of Time-Varying Electric Fields on a 2-Level Ion System

    Hello! If I have an ion which can be treated as a 2 level system, in a time varying electric field (the variation of the field doesn't need to be on or close to resonance, but for simplicity we can assume it is an oscillatory field) can I simply separate the problem into a center of mass motion...
  8. gggnano

    Can the thrust of Ion Thruster be increased at the cost of speed?

    Based on the little I know ion thrusters seem extremely impractical on earth, even because speeds over 20,000-30,000+km/h will result in immense friction and fire, so why not cut the high speed somehow and increase thrust which is abysmall? For example: the ions passing through a medium?? Wider...
  9. C

    A How making the ions leave the cavity in a ion sources

    Ion sources are devices that allow creating ion beams (e.g. argon ions) and to project them outside the device, for example to be further processed by a particle accelerator, or to irradiate materials or biological tissues etc. The ions are usually created by a plasma inside a cavity filled...
  10. K

    I Ion Ablation Target Experiment: Estimating Energy Spread

    Hello! For the experiment I am working on we are using as the ion source an ablation target. We have a 1 inch coin of the material of interest (ytterbium currently) and we send laser pulses to it (we are using a 532 Nd:YAG laser). Can someone point me towards a paper (or tell me from their...
  11. C

    A Penetration depth of a ion beam coupled with an EM wave

    A Ion source is a device that allows creating ion beams (e.g. argon ions) and to project them outside the device, for example to be further processed by a particle accelerator, or to irradiate materials or biological tissues etc. Now, suppose the ion beam is coupled with an EM wave, especially...
  12. K

    Finding the total charge in an electrolyte

    Total number of charges = charge per ion * number of ions = 1.6*10^-19 * number of combined ions Solution: 1.6* 10^-19 * number of negative ions
  13. Anmoldeep

    B Ion Trap and Time-Varying Potentials

    Ion traps are very complex, but one of my Physics Olympiad textbooks (this is not homework) presents a simplified model of a resonating charged particle in an ion trap which according to me is wrong, there is either something missing or something overspecified here. A tuned circuit...
  14. Anmoldeep

    Time dependant Potential Energy in ion trap

    Ion traps are very complex, but one of my Physics Olympiad textbooks presents a simplified model of a resonating charged particle in an ion trap A tuned circuit consists of an inductor and a parallel plate capacitor (capacitance C and plate separation d). It has a resonating frequency ##\nu...
  15. yucheng

    Is the potential energy of an ion in a lattice ##U_0## or ##U_0/2##?

    Potential energy in a two-dimensional crystal Consider the potential energy of a given ion due to the full infinite plane. Call it##U_{0}##. If we sum over all ions (or a very large number##N##) to find the total##U##of these ions, we obtain##N U_{0}##. However, we have counted each pair twice...
  16. T

    Ion flow through a charged tube

    Suppose we have a charged metal tube through which charged ions of compressible fluid is passing. I want to know whether the boundary layer will still form that will resist the flow or the flow will be smoother. We all know how strong electromagnetic force is and this will push the ions away...
  17. I

    Chemistry Platinum ion electron configuration

    The answer is [Xe] 4f14 5d8. Why does platinum (and other 6th and 7th period d-block elements) have 4f14 instead of 4f7? Thanks.
  18. naviakam

    How Does Compressing Fully Ionized Gas Accelerate Ions to High Energies?

    Fully ionized gas, if compressed to a cylinder of mm scale, collapses rapidly and accelerates the e/ions to very high energies (MeV). The temperature in the compressed gas is around 100 eV. What could be the possible acceleration mechanism?
  19. S

    Chemistry Drawing resonance structure for this O-CH2 ion

    ion shown: My answer: the following is the answer of the question: I identified the major contributor correctly, but the resonance structures, but the second resonance I drew is missing in the answer sheet. Can anyone tell me why the second resonance structure is not part of the answer...
  20. F

    Chemistry What ion is Aluminum likely to form?

    A self test question from Chemical Principles(Atkins/Jones). Other than rote memorization I don’t see how to do this. The review section references the Periodic Table and, for elements on the right side of the table, one can use 18 minus the group number which would give Al(superscript 5+) since...
  21. R

    Is it possible to put multiple accelerator grids in an ion engine?

    Is it possible to put multiple accelerator grid in ion engine instead of one? So we will get higher exhaust velocity and benefit for us right? or is there any disadvantages?
  22. il postino

    Chemistry Calculate the solubility (common ion) buffered

    Data: ## pK_{ps} , pKa_{1} , pKa_{2} ## Could you guide me to start solving? Thank you!
  23. il postino

    Chemistry Calculate the activity of the chloride ion in a solution

    Hi everyone! I have to calculate the activity of ##Cl^{-}## I have a solution formed by ## Na_{2}SO_{4}## 0.0016 m + ##NaCl## 0.0014m + ##FeCl_{3}## 0.0012m I calculated the ionic strength ##I## ##I=0.0134## The activity of the chloride ion is ##a_{Cl^{-}}=m_{Cl}*\gamma _{Cl}## But I don't...
  24. sergey_le

    Calculating Concentrations in a Saturated Solution of CaCl(2) and Ca(OH)2

    Summary:: finding concetrations [Thread moved from the technical forums] i did a lab experiment and I'm a little confused about what i should do. i got a solution of CaCl(2) 1.5 gr and Ca(OH)2 5gr in 100ml that i prepared 2 weeks ahead . after filttering the solution i got a saturated...
  25. dRic2

    I What are the differences between Ion Linac and Electron Linac?

    Hi, I've been reading out of curiosity about linear accelerators to get a general ideal of the principles behind them. My main concern is that, as far as I could tell, there are two different types (I'm sure there are more than two, but I want to keep things simple) of Linear Accelerators...
  26. patric44

    Perturbation treatment of hydrogen molecular ion

    hi guys i am a the third year undergrad student and in this 2nd semester in my collage we should start taking quantum mechanics along with molecular physics , our molecular physics professor choose a book that we are going to take which is " molecular physics by wolfgang Demtroder " when i...
  27. B

    Find the mass of this ion moving in a magnetic field

    I had started off by equating the magnetic force to the centripetal force, to find the mass of a single ion. Then calculated the mass of what 1 mole of that ion would weigh to identify what the ion is Hence the answer would be nitrogen (option C) as 1 mole of nitrogen weighs 14g Would this...
  28. pinball1970

    A Quantum measurement of a Strontium ion

    I cannot post the science alert article where I saw this. Apologies, this put the study in layman's. @PeterDonis @vanhees71 et al will not need that. Is this significant? Could the wave function not instantaneously collapse?
  29. r12214001

    Chemistry Complex ion oxidation state (with pic)

    question fig: solution manual: my solution: oxidation state of central cobalt is +6 due to 6 oxygen surrounding it,The other cobalt is +2 due to 2 oxygen surrounding it with NH3 ligand which is no count for oxidation state.
  30. M

    Is ablative laser propulsion a better option than Ion engines?

    I’m trying to find something that can replace Ion engines in my Star Wars story. Ablative laser propulsion seems like a good bet because it works in both atmosphere and a vacuum and just seems better than Ion engines.
  31. S

    Is the Ion Bound with this Energy Minimization?

    From what we did in class, I think we need to minimize the energy with respect to a. Like ##E = \frac{\hbar ^2}{m} a^2 - 2 e^2 a + \frac{5}{8} e^2 a = \frac{\hbar ^2}{m} a^2 - \frac{11}{8} e^2 a ##, then minimize it Finding the minimum value: ## - (\frac{11}{16})^2 \frac{m e^4}{\hbar^2} ##...
  32. Indula

    What's electropositive ion flux in a plasma?

    Is it the same as the plasma density ? Is it directly proportional to the plasma density ? Does this term only applies to electropositive plasma or applies to any plasma?
  33. C

    A What is the definition of 'ground state',considering H- ion = -14.35eV

    If 'ground state' is the lowest energy state, and H atom takes -13.6eV to ionise while H- takes -14.35eV, why is H- not considered the 'ground state'? Is that definition wrong? What is the definition of 'ground state' that "fixes" this?
  34. Jamister

    I Is Total Angular Momentum Conserved in the Hydrogen Ion Molecule H₂⁺?

    in the book Molecular Physics of Wolfgang Demtroder, he claims for hydrogen ion molecule ##H_2 ^+## the total angular momentum in absolute value is a constant quantum number. I never saw it any other book and I think it's wrong, because there is no reason for it and he doesn't prove it. here is...
  35. RamSkull

    Are CRTs Suitable for Use in Ion Thrusters?

    Hello! I'm trying to make a simple ion thruster that will be used in a science fair so I'm not concerned about its efficiency but just creating at least some thrust. However I wanted to make it as close as reality as possible, using every component and respecting its details if possible. Ion...
  36. Haorong Wu

    Quantum Any prerequisite courses before ion traps?

    Hi. I'm currently reading papers about ion traps. There are several concepts that I'm not familiar with, such as rf trap, interactions between pulses and ions, Rabi frequency, resonant excitation of internal transition, Lamb-Dicke parameter, Raman scattering and so on. From any courses or...
  37. C

    I How to measure ion energy in a plasma?

    I was looking at things today and read (on wiki) that the use of Thompson Scattering reveals electron temperature in a plasma, not ion temperature. I thought that's how ion temp was measured (or maybe it is and the wiki text was incomplete)? Could someone please clarify how ion temperatures in...
  38. somasimple

    Ion migration by diffusion in an electric field

    Hi, A solution contains some ions (charged particles). We are only interested in my exemple to positive ions. It is assumed that these ions acquired some mobility under a concentration gradient. Their direction is A to B. Then these ions encounter/cross an electric field which is oriented from B...
  39. Harperchisari

    Thermodynamics in an ion beam?

    Hi there, I'm trying to design an ion beam source, but having some issues with the thermodynamics of it. I'm no expert in thermodynamics, but I do understand some. I'm trying to find an equation which I can use to find the amount of energy I need to put into a set mass of a set material in order...
  40. M

    I How do ion sources in cyclotrons work?

    I've been learning about cyclotrons recently and have trouble understanding how the ion source works. I have done some research and found that duoplasmatrons are some forms of ion sources but i don't think that's legit. I also found something called RF ion sources, but not sure how they work. I...
  41. M

    Understanding Polyatomic Ion Charges and Number of Oxygen

    I have recently started self studying chemistry and I am at the point where I'm learning to name chemicals given chemical formulas and vice versa. (Like Iron (III) Oxide --> Fe2O3). I am having trouble with doing this process for polyatomic ionic compounds. I can't seem to remember some the...
  42. D

    Secondary ions entering a mass filter in Secondary Ion Mass Sprectrometry (SIMS)

    Hello, I have a question about secondary ions entering a mass filter in Secondary Ion Mass Sprectrometry (SIMS). We know that secondary ions are sputtered from surface of studied sample. Those secondary ions are entering a mass filter which sort them out due to their mass/charge ratio. After...
  43. A

    How does ion aircraft propulsion work?

    I saw a video on youtube and it explains in a vague way how the system works, so there is a potential difference between two sets of electrodes and air between them is ionized in the presence of the E field but how muhc is it ionized? Because I get the impression that the ionization is not in...
  44. Javier Lopez

    Rotating speed of a proton ion

    I tried to calculted the rotating speed fro a proton from the clasical point of view by using its magnetic moment and the moment of a rotating sphere uniformly charged as example here: https://ocw.mit.edu/courses/physics/8-07-electromagnetism-ii-fall-2012/exams/MIT8_07F12_quizsol2.pdf It is said...
  45. Javier Lopez

    I Ion sensor for 1e20 ions/m3 density

    What kind of ion sensor can I use in the range 1e19to 1e22 ions/m3? (corresponds to 0.1 to 5 pascals if non ionized) Does it exist any sensor based in the charge capacity?
  46. Javier Lopez

    A Ion Generation Troubleshooting: Overcoming Limitations in Small Ion Accelerators

    I have to increase ion generation in a small ion accelerator but I have troubles to go over 20mA (1.27e17 ions/second). I can modulate up to 40 Mhz at 1kV. What ion generator it is recommended gor large ion flux?, I can work in pulse generation.
  47. Javier Lopez

    I Stopping power for a proton ion gun through a Boron-11 sheet 1mm thick

    Hello, I need the stopping power for a proton ion gun through Boron-11 sheet 1mm thick. I have the following table obtained from here: https://www-nds.iaea.org/stopping/stopping_hydr.html Where the unit is in 1-15*eV*cm2/atom: Then I calculated for 600keV protons at table 5.1eV*cm2/atom. I...
  48. Vishesh Jain

    Distance to 3rd and 5th nearest ion to S2- in ZnS structure

    Hey folks ZnS has a ccp structure with S2- ions forming FCC lattice with Zn2+ ions at half the tetrahedral voids Attached is a table showing no. of nearest neighbours and their distance for an S2- ion 'a' is edge length of the unit cell I want to know how the distance to the 3rd & 5th...