Abstract: The disclosed invention relates to novel biocompatible firefighting foam compositions that include a deep eutectic solvent. Disclosed are methods of making and using firefighting foams containing deep eutectic solvents, which may also be used in existing fire foam compositions as drop in solvent additives. The deep eutectic solvents may also be used in or as a principle component of surrogate firefighting foam compositions.

Abstract: A landing pad including at least one integrally formed elongated hollow decking unit having an elongated landing plate with a plurality of holes, an elongated base plate aligned longitudinally with respect to the elongated landing plate which is designed as an orifice plate and spaced a distance apart from the elongated landing plate, and two elongated side wall plates connecting the elongated landing plate to the elongated base plate. The plurality of holes may be configured to drain unburned fuel spilled on the elongated landing plate through the plurality of holes into the elongated hollow decking unit and to suppress flame of burning fuel from propagating through the plurality of holes into the elongated hollow decking unit by reducing the temperature of drained unburned fuel. The distance apart between the elongated landing plate and the elongated base plate may be configured to prevent re-ignition of the drained unburned fuel on the elongated base plate inside the elongated hollow decking unit.

Abstract: A system and method monitor operation of a compressor, determine whether the operation of the compressor is outside of a designated range of values, and, responsive to determining that the operation of the compressor is outside of the designated range of values, one or more of (a) prevent communication of a signal to a system controller that controls operation of the compressor, (b) direct a gas from a reservoir to a pressure sensor used by the system controller to determine a gas pressure generated by the compressor, and/or (c) communicate the signal to the system controller that controls operation of the compressor.

Abstract: A composition for a food safe firefighting agent includes: xanthan gum, water, and a surfactant.

Abstract: A method for use with an underground network that includes a plurality of locations. The method includes receiving sensor data from at least one sensor located at a first of the plurality of locations and determining the sensor data indicates that a fire is in progress. The method includes identifying one or more of the locations as one or more potential combustion locations and assigning an estimate of a probability to each of the potential combustion location(s). The estimate estimates a likelihood that the potential combustion location is an actual combustion source. The method may include displaying the estimate of the probability assigned to each of the one or more potential combustion locations.

Abstract: A firefighting system can include an aqueous solution, including an ionic liquid surfactant, and an application mechanism configured to disperse the solution toward a fire.

Abstract: The firefighting helicopter fans comprise a left pivoting cowled fan and a right pivoting cowled fan mounted onto the sides of a helicopter. The fans may be used to create an airstream, which counters the prevailing wind and/or blows flames and embers away from unburned materials. The fans are each protected by a cowl that surrounds the blades to protect the blades and direct the airstream. The left pivoting cowled fan and the right pivoting cowled fan are each coupled to the helicopter by a pivot axis and a pivot motor which allows the fanes to be aim directly forward, directly down, or any angle in between.

Abstract: A method for transporting liquid with a UAV transport that includes docking the UAV transport with a first station and supplying the UAV transport with liquid from the first station. The UAV transport undocks from the first station and flies to the vicinity of a second station. The UAV transport docks with the second station and delivers at least a portion of the liquid to the second station. A UAV for use therewith and a method for maintaining a feed tray at the second station are provided.

Abstract: A composite material comprising 10-98 wt. % of a bio-based particulate or fibrous filler and at least 2 wt. % of a polyester derived from an aliphatic polyalcohol with 2-15 carbon atoms and a polyacid, wherein the polyacid comprises at least 10 wt. % of tricarboxylic acid. Preferably, the filler is in the form of particles, fibers, and/or random or non-random layers. A plant-based filler may be used, in particular a cellulosic or lignocellulosic material, more in particular one or more materials selected from wood chips, wood flakes, sawdust, pulp, e.g., pulp of (recycled) paper or other fiber pulp, and plant-derived fibers such as cotton, linen, flax, and hemp. An animal-derived filler, in particular an animal-derived fiber such as wool, hair, silk, or feathers may also be used. Preferably the polyalcohol is selected from one or more of glycerol, sorbitol, xylitol, mannitol, 1,2-propane diol, 1,3-propane diol, and 1,2-ethane diol, in particular glycerol.

Abstract: A composite material comprising 10-98 wt. % of a bio-based particulate or fibrous filler and at least 2 wt. % of a polyester derived from an aliphatic polyalcohol with 2-15 carbon atoms and a polyacid, wherein the polyacid comprises at least 10 wt. % of tricarboxylic acid. Preferably, the filler is in the form of particles, fibers, and/or random or non-random layers. A plant-based filler may be used, in particular a cellulosic or lignocellulosic material, more in particular one or more materials selected from wood chips, wood flakes, sawdust, pulp, e.g., pulp of (recycled) paper or other fiber pulp, and plant-derived fibers such as cotton, linen, flax, and hemp. An animal-derived filler, in particular an animal-derived fiber such as wool, hair, silk, or feathers may also be used. Preferably the polyalcohol is selected from one or more of glycerol, sorbitol, xylitol, mannitol, 1,2-propane diol, 1,3-propane diol, and 1,2-ethane diol, in particular glycerol.

Abstract: The present invention relates to a fire-extinguishing composition containing an alcohol/phenol compound and its derivative. The fire-extinguishing composition releases a great quantity of active fire-extinguishing particles by making use of the heat generated from combustion of a pyrotechnic agent. The fire-extinguishing composition containing an alcohol/phenol compound and its derivative in the present invention reacts at a high temperature to generate a great quantity of nanoscale active fire-extinguishing particles, takes reaction with one or more of O-, OH-, H-free radicals necessary for a chain combustion reaction, so as to cut off the chain combustion reaction and take physical and chemical inhibiting effects to jointly achieve a fire extinguishing effect at the same time. Meanwhile, it takes a synergistic interaction effect with pyrotechnic agent to further raise the fire extinguishing efficiency of the fire extinguishing agent and greatly shorten the effective fire extinguishing time.

Abstract: The present invention relates to a fire-extinguishing composition containing a carboxylic acid derivative. The fire-extinguishing composition releases a great quantity of active fire-extinguishing particles by making use of the heat generated from combustion of a pyrotechnic agent. The fire-extinguishing composition containing a carboxylic acid derivative in the present invention is decomposed at a high temperature to generate free radicals and takes reaction with one or more of O—, OH—, H— free radicals necessary for a chain combustion reaction through the free radicals, so as to cut off the chain combustion reaction and take physical and chemical inhibiting effects to jointly achieve a fire extinguishing effect at the same time. Meanwhile, it takes synergistic interaction effects with the pyrotechnic agent to further raise the fire extinguishing efficiency of the fire extinguishing agent and greatly shorten the effective fire extinguishing time.

Abstract: A personal care composition comprising a dermatologically acceptable carrier, and from about 3 wt % to about 40 wt % of at least one undecyl sulfate compound selected from the group consisting of: a) R1—O(CH2CHR3O)y—SO3M; b) CH3—(CH2)z—CHR2—CH2—O(CH2CHR3O)y—SO3M; and c) mixtures thereof; where R1 represents CH3(CH2)10, R2 represents H or a hydrocarbon radical comprising 1 to 4 carbon atoms such that the sum of the carbon atoms in z and R2 is 8, R3 is H or CH3, y is 0 to 7, the average value of y is about 1 when y is not=0, and M is a mono-valent or di-valent, positively-charged cation.

Abstract: The present invention provides a method for preventing and extinguishing fire, the method for preventing and extinguishing fire being effective against fire caused by a pyrophoric material and a water prohibitive substance. The method for preventing and extinguishing fire of the present invention is characterized in that a fire extinguishing foam composition is supplied to a flame caused by the combustion of a pyrophoric material and a water prohibitive substance whereby the flame is suppressed or extinguished, and that a combustible material is changed to an inert substance by a hydration reaction, the combustible material being a pyrophoric material or a water prohibitive substance.

Abstract: A device for suppressing fire inside a container includes a support structure configured to be mounted inside a vehicle at a position associated with at least one location configured to receive a container. The device further includes a deployment structure coupled to the support structure and a penetrator assembly coupled to the deployment structure. The penetrator assembly includes a nozzle having a tip configured to pierce a container and an actuator associated with the nozzle. The actuator is configured to extend the tip of the nozzle such that it pierces a container. The support structure and the deployment structure are configured such that the penetrator assembly is movable in at least one plane with respect to the support structure, and the penetrator assembly is configured to receive fire suppressant and direct the fire suppressant into the container.

Abstract: An automatic fire extinguishing system includes a canister having a central axis, an outlet port disposed on the canister, a dip tube disposed in the canister about the central axis and in partial fluid communication with the canister and coupled to the outlet port, a propellant gas mixture of CO2 and N2 disposed within the canister and a gaseous fire suppression agent disposed in the canister.

Abstract: A powder composition includes starch, acrylic acid homopolymer salt, and clay. The powder composition forms an aqueous dispersion having a neutral pH when added to water and is capable of clinging to a surface.

Abstract: Fire-retardant powder comprising at least 30% by weight of Lewis acid, at least 5% by weight of alkaline bicarbonate, and at least 3% by weight of silica, and method of manufacturing such fire-retardant powder. A building material preferably comprising natural fibers and comprising at least 5% by weight and at most 30% of such powder.

Abstract: An automatic fire extinguishing system includes a canister having a central axis, an outlet port disposed on the canister, a dip tube disposed in the canister about the central axis and in partial fluid communication with the canister and coupled to the outlet port, a propellant gas mixture disposed within the canister; and a gaseous fire suppression agent disposed in the canister, wherein a diameter of the outlet port is sized relative to a pressure of the propellant gas mixture.

Abstract: An automatic fire extinguishing system includes a canister having a central axis, an outlet port disposed on the canister, a dip tube having dip tube side holes and inlet openings, and disposed in the canister about the central axis and in partial fluid communication with the canister and coupled to the outlet port, a propellant gas mixture disposed within the canister and a gaseous fire suppression agent disposed in the canister.

Abstract: Rock dust is applied to a mine wall for mine fire suppression in combination with a chemical foam, by generating the foam from air and a foamable liquid in a mixing chamber, and delivering the foam through one flexible conduit and a suspension of rock dust in water through another flexible conduit to a combiner, and causing the combined foam, rock dust and water to pass through a flexible hose to a delivery nozzle from which it is applied to a mine wall.

Abstract: An assembly for mixing and metering a foaming agent with a pressurized fluid output of a fire extinguisher, the extinguisher including a body with a trigger for issuing the fluid through an outlet. The assembly includes a manifold adapted to being attached at an inlet end to the extinguisher outlet, the manifold having an outlet end which is adapted to engage with an inlet of a flexible hose. A canister contains a volume of a fire retardant (dry or foaming) agent and is engaged to an intermediate location of the manifold between the inlet and outlet. In this manner, the manifold mixes the foaming agent with the fluid output prior to delivery through the hose.

Abstract: Methods and systems are provided for reducing fuel vapor generation from a fuel tank in a hybrid vehicle. A layer of gel-foam fire retardant is layered over the surface of fuel in the fuel tank. In response to the layer being below a fuel level in the fuel tank, fuel pump operation may be automatically disabled.

Abstract: A fire suppression system for an aircraft includes an air separation module configured to receive exhaust air and ram air, conditioned compressor bleed air, and any combination thereof. The air separation module is also configured to provide nitrogen-enriched air and inert gas. The nitrogen-enriched air flows into a nitrogen-enriched air distribution network for fuel tank inerting. The inert gas flows into an inert gas distribution network for fire suppression in areas of the aircraft other than fuel tanks.

Abstract: Water is mixed with fire suppressant polymer in a mixer absent a power source. The mixer receives water through a water inlet with water exhibiting high velocity and associated hydrodynamic force. Such velocity is achieved by locating the water inlet connected to a float or other part of an aircraft so that when the aircraft flies over water with the float dipping into the water, water is driven through the opening and into the water inlet of the mixer. A polymer inlet passes into the mixer. A bend is located downstream of the water inlet and the polymer inlet. The bend exhibits sufficient resistance to fluid flow direction therethrough that the polymer is sheared and thoroughly mixed and activated with the water. A colorant inlet is optionally provided within the mixer and the water and polymer mixture is then discharged into a tank for later utilization at a firefighting location.

Abstract: A fire suppression system for a container including a first tank containing a first liquid component of a two-part foam and a second tank containing a second liquid component of the foam. The system also includes at least one liquid component release device configured to be selectively capable of releasing the first and second components from their respective containers upon receipt of a signal from a fire detector upon detection of a fire. The two-part foam components are propelled through the system by a pressurized propellant that, upon release of the release device, causes the exit of the foam components from their respective tanks, through a mixing conduit to at least one nozzle. The nozzle is configured to spray the liquid component foam mixture into the container wherein the foam cures into a substantially semi-rigid, closed cell foam that is substantially impermeable and may have charring and/or intumescence properties.

Abstract: A calibration and verification system and method for dynamically controlling sequential delivery of mixtures containing a fire suppression agent to detection locations to simulate an agent discharge during a flight operation of an aircraft and for allowing direct monitoring of the concentration amounts at the detection locations to adjust a testing operation accordingly. Each of the mixtures is prepared with a precise concentration amount of the agent. The system and method include a remote test sequence unit for determining an optimal testing time period during a flight operation to remotely control the discharge and monitoring of the agent. Prior to the optimal testing time period, an airflow at an altitude of the flight operation is drawn through each of a plurality of detectors to tare out the characteristics of a surrounding environment using a processor, thereby establishing a measurement baseline for each of the plurality of detectors.

Abstract: Fire suppression apparatuses include a housing with gas generant material disposed therein, an initiator for igniting the gas generant material, and a cooling system. The cooling system includes a first chamber with a coolant material disposed therein and a second chamber. The coolant material is caused to flow from the first chamber into the second chamber to cool gas formed by the ignition of the gas generant material upon exiting from the housing under pressure. The cooling system may further include a piston disposed within the first chamber and movable responsive to gas pressure. Methods for cooling a fire suppressant gas and methods for suppressing a fire include flowing a fire suppressant gas into first and second chambers of a cooling system, flowing a coolant material from the first chamber into the second chamber, and contacting the fire suppressant gas with the coolant material to cool the fire suppressant gas.

Abstract: A fire suppression non-aqueous liquid concentrate includes starch, a pseudo-plastic, high yield, suspending agent, a C10-18 paraffin or a C10-18 olefin, a non-ionic surfactant, and an alcohol amine neutralizer. The non-aqueous liquid concentrate forms a dilute dispersion when added to water. The dilute dispersion clings to a surface, and forms an intumescent char coating upon fire contact.

Abstract: A fire suppression composition includes starch, a pseudo-plastic, high yield, suspending agent, and hydrophobic agglomerating material.

Abstract: A fire suppressant mixture comprising: an organic or supplemental organic fire suppressant compound; a halogen element, and an organic compound, wherein the organic fire suppressant compound, the halogen element and the organic compound are combined such that a boiling point of the mixture is lower than the boiling point of the organic fire suppressant. In some embodiments, the organic fire suppressant compound is FK 5-1-12 and the organic compound is carbon dioxide. In other embodiments, the mixture is supplemented with an additional organic compound such as CF3I or 2,2-Dichloro-1,1,1-trifluoroethane (R123), or an halogen element. In some embodiments an inorganic pressurizing gas, such as nitrogen, is also added.

Abstract: A fire extinguishing composition generating fire extinguishing substance through chemical reaction of ingredients at high temperature, wherein: the fire extinguishing composition comprises a flame retardant, an oxidant, a reducing agent and an adhesive; contents of each ingredient are: the flame retardant: 50 wt % to 90 wt %; the oxidant: 5 wt % to 30 wt %; the reducing agent: 5 wt % to 10 wt %; the adhesive: 0% to 10 wt %. In a usage of the fire extinguishing composition, a pyrotechnic agent is adopted as a heat source and a power source; and the purpose of fire extinguishing is achieved by: igniting the pyrotechnic agent, and the oxidant and the reducing agent in the fire extinguishing composition are reacted to generate the in the use of high temperature produced by burning the pyrotechnic agent. by burning the pyrotechnic agent, so as to implement fire extinguishing. Different from the traditional aerosol generating agent, there is no external heat source, and the composition itself does not burn.

Abstract: The present invention relates to a fire extinguishing composition which generate fire extinguishing substance by high temperature sublimation; the fire extinguishing composition comprising a fire extinguishing material which, in a heating process, can sublimate and release a fire extinguishing substance with fire extinguishing properties; the content of the fire extinguishing material is at least 80 wt %. When the fire extinguishing composition is in use, a pyrotechnic agent as a heat source and a power source; and the purpose of fire extinguishing is achieved by: igniting the pyrotechnic agent, generating a large quantity of fire substance from the fire extinguishing composition in the use of high temperature produced by burning pyrotechnic agent, and the fire substance sprays out together with the pyrotechnic agent.

Abstract: A unique method for suppressing the spread of and extinguishing underground electrical fires in confined areas such as tunnels and conduits. A super absorbent polymer is mixed with water to form a hydrated super absorbent polymer and this admixture is applied to an electrical fire. The admixture has superior fire suppression and extinguishing properties than the fire suppression and extinguishing properties of plain water. The admixture has the ability to cling to the object(s) to which it has been applied and both cool down the object(s) and block the fire from reaching the object(s). The super absorbent polymer and water admixture also encapsulates the noxious and toxic gases produced by electrical fires and prevents the release of these toxic gases into the atmosphere. Finally, the super absorbent polymer and water mixture retains the ash, particulates, and other byproducts of the electrical fire to enable a thorough cleanup.

Abstract: A firefighting apparatus comprising a controller, and a hydraulic pump driven by a power-take-off and operable to supply a hydraulic fluid under pressure. A water pumping subsystem is powered by the hydraulic fluid and operable to supply water under pressure to a conduit, wherein a flow rate of water is substantially regulated by controlling the hydraulic fluid input to the water pumping subsystem. A chemical foam subsystem is powered by the hydraulic fluid and operable to inject foam at a predetermined flow rate into the conduit, wherein the flow rate of the foam is substantially regulated by controlling the hydraulic fluid input to the chemical foam subsystem. An electrical power generator subsystem is powered by the hydraulic fluid and operable to generate electrical power, wherein the frequency and voltage of the generated power is substantially regulated by controlling the hydraulic fluid input to the electrical power generator subsystem.

Abstract: Embodiments of the invention provide a fire-fighting system including a low-pressure system and an ultra-high pressure system (UHPS). The fire-fighting system can also include a foam proportioning system, which can inject a foamant into the low-pressure system and/or the UHPS. The low-pressure system and the UHPS can be simultaneously operated. Some embodiments of the fire-fighting system can be installed on aircraft rescue fire fighting (ARFF) vehicles.

Abstract: The present invention relates to a ferrocene-based fire extinguishing composition. The ferrocene-based fire extinguishing composition comprises ferrocene, a ferrocene derivative, or a combination thereof at a content of 25 mass % or more; when in use, a pyrotechnic agent is used as a heat source and a power source, the pyrotechnic agent is ignited, and the high temperature generated by the combustion of the pyrotechnic agent is utilized to make a fire extinguishing composition produce a large amount of fire extinguishing substance, which is sprayed out together with the pyrotechnic agent, so as to achieve the purpose of extinguishing a fire. Compared with a conventional fire extinguishing composition, a more efficient and safer fire extinguishing composition is provided.

Abstract: A unique method for suppressing the spread of and extinguishing underground electrical fires in confined areas such as tunnels and conduits. A super absorbent polymer is mixed with water to form a hydrated super absorbent polymer and this admixture is applied to an electrical fire. The admixture has superior fire suppression and extinguishing properties than the fire suppression and extinguishing properties of plain water. The admixture has the ability to cling to the object(s) to which it has been applied and both cool down the object(s) and block the fire from reaching the object(s). The super absorbent polymer and water admixture also encapsulates the noxious and toxic gases produced by electrical fires and prevents the release of these toxic gases into the atmosphere. Finally, the super absorbent polymer and water mixture retains the ash, particulates, and other byproducts of the electrical fire to enable a thorough cleanup.

Abstract: A fire suppression composition includes starch, a pseudo-plastic, high yield, suspending agent, hydrohopbic agglomerating material, and a neutralizer.

Abstract: A nozzle assembly for encapsulating a gaseous solution in bubbles comprises a discharge tube having a diffuser and a foam solution spray nozzle mounted therein. The discharge tube has upstream and downstream ends. The discharge tube has a front face at the upstream end with a first opening configured to be joined to a gas supply line that provides a gaseous solution and a second opening configured to receive a non-expanded foam solution. The downstream end of the discharge tube is open. A chamber is formed within the discharge tube to receive the gaseous solution at the upstream end and release the gaseous solution through the diffuser into the discharge tube towards the downstream end.

Abstract: A method for mixing fire fighting gel in situ within a water tank of a fire fighting aircraft. A first step involves mounting a chemical tank to a fire fighting aircraft having a water tank. A second step involves injecting gel forming chemical from the chemical tank into a turbulent flow of water entering the water tank of the aircraft to achieve a required ratio of gel forming chemical and water, with the turbulent flow of water serving to mix the gel forming chemical with the water.

Abstract: A fire suppression system for an aircraft includes an air separation module configured to receive exhaust air and ram air, conditioned compressor bleed air, and any combination thereof. The air separation module is also configured to provide nitrogen-enriched air and inert gas. The nitrogen-enriched air flows into a nitrogen-enriched air distribution network for fuel tank inerting. The inert gas flows into an inert gas distribution network for fire suppression in areas of the aircraft other than fuel tanks.

Abstract: The invention relates to a compressed air foam producer, wherein a fire or decontamination specific additive is injected directly into the foam forming flow supplied to the main water flow and/or the main water flow. A mixing pump for the foaming agent draws off an auxiliary and motive water flow, wherein initially the additive and then the foaming agent is injected. The foaming agent-additive-water mixture, which is produced directly on site, is mixed well together and with the main water flow ensuring a fine, uniform distribution of the additives in the compressed air foam. The thus produced compressed air foam ensures optimal, economical and environmentally friendly fire-fighting and decontamination.

Abstract: A fire and explosion suppression system comprises a source (5) of high pressure water which is fed to a misting nozzle (13) at one input of a mixing unit (6), and a source (14) of high pressure inert gas, such as nitrogen, which is fed along a pipe (20) to another input of the mixing unit (6). Inside the mixing unit (6), water mist, in the form of an atomized mist of very small droplet size is mixed with the pressurized gas and exits the mixing unit (6) at high pressure and high velocity along a pipe (22) and is thence discharged through spreaders (26, 28). The source (5) of the water is pressurized by a feed (30) from the source of pressurized inert gas. The mass flow rate of the water will therefore reduce as the pressure of the gas decays. This tends to maintain the ratio of the mass flow rate of the water to the mass flow rate of the gas constant. This is found to produce and maintain an advantageous distribution of droplet size in the discharged unit.

Abstract: This invention comprises a method of dispensing water-based decontaminants from a dispenser, comprising the steps of: (a) filling one or more tanks each with respective solutions of chemicals and water; (b) pumping the solutions from the tanks in respective hoses, each of the tanks being evacuated under the urging of a respective pump; (c) mixing the solutions at a static mixer after evacuation of the solutions from the tanks to form a mixture; (d) adding water to the mixture at the static mixer; and (e) dispensing the water-added mixture onto an incident site.

Abstract: A firefighting station is provided. The firefighting station includes an optional portable cart, one or more chemical foam proportioners, one or more first manifolds, one or more first valves, one or more first check valves, one or more second manifolds and one or more optional chemical fire suppression agent reservoirs. Methods of suppressing or preventing a fire are also provided.

Abstract: A compressed gas foam system is provided. The compressed gas foam system includes one or more optional fluid pumps, one or more mixing devices, one or more optional foam systems; one or more optional gas compressors, and a system controller. A method of using the compressed gas foam system is also provided.

Abstract: The method is for continuously producing compressed-air foam, notably for fire fighting or for decontamining, by supplying both compressed air and a mixture of water and at least a foaming agent to a foaming chamber (5) outputting foam to a nozzle (9) via a pipe (8). The mixture of foam agent and water and the compressed air are each continuously supplied to the foaming chamber (5) at a constant pressure and at a constant volume flow rate, e.g. by means of pressure regulators (1, 2) and of flow rate regulators (3, 4). The foam pressure is regulated at the outlet of the foaming chamber (5) for maintaining the foam mixing pressure in the foaming chamber constant, preferably by a self-operating valve (6). The foaming chamber can advantageously be of a static type comprising sieves.

Abstract: Rock dust is applied to a mine wall for mine fire suppression in combination with a chemical foam, by generating the foam from air and a foamable liquid in a mixing chamber, and delivering the foam through one flexible conduit and air-entrained rock dust through another flexible conduit to a portable assembly composed of a Y-joint and a delivery nozzle for combining the foam and rock dust and applying the combination directly to a mine wall.

Abstract: A method of treating a material to improve flame retardancy, the method comprising applying to the material urea, phosphorous acid or a salt thereof, and a base comprising a monovalent metallic cation.