Tigerair Singapore Flights Schedule & Promotion Price 2017 in Airpaz


Get Tigerair Singapore Flights Promotion Price 2017 and Plan Your Trip with Airpaz Today! Airpaz Offers Tigerair Online Booking with The Best Promotion Price


Special Price Date List
Tiger Air

Tigerair Singapore (TR)

 Free Cabin 10kg
 Check-in 120 min before
 Online Check-in

Promo Flight

view more promo

Top Route

tiger airways route
Singapore to Cebu Tiger Air flights from Singapore to Cebu
Cebu to Singapore Tiger Air flights from Cebu to Singapore
Singapore to Kalibo Tiger Air flights from Singapore to Kalibo
Kalibo to Singapore Tiger Air flights from Kalibo to Singapore
Singapore to Iloilo Tiger Air flights from Singapore to Iloilo
Singapore to Butuan Tiger Air flights from Singapore to Butuan
Singapore to Puerto Princesa Tiger Air flights from Singapore to Puerto Princesa
Singapore to Dumaguete Tiger Air flights from Singapore to Dumaguete
Singapore to Dipolog Tiger Air flights from Singapore to Dipolog
Singapore to Zamboanga Tiger Air flights from Singapore to Zamboanga
Naga to Singapore Tiger Air flights from Naga to Singapore
Legazpi to Singapore Tiger Air flights from Legazpi to Singapore
Singapore to Naga Tiger Air flights from Singapore to Naga
Singapore to Legazpi Tiger Air flights from Singapore to Legazpi
Busuanga to Singapore Tiger Air flights from Busuanga to Singapore
Singapore to Busuanga Tiger Air flights from Singapore to Busuanga
Singapore to Roxas Tiger Air flights from Singapore to Roxas
Singapore to Ozamiz Tiger Air flights from Singapore to Ozamiz
Laoag to Singapore Tiger Air flights from Laoag to Singapore
Camiguin to Singapore Tiger Air flights from Camiguin to Singapore
Singapore to San Jose Mindoro Tiger Air flights from Singapore to San Jose Mindoro
Taipei Taoyuan to Cebu Tiger Air flights from Taipei Taoyuan to Cebu
Cebu to Taipei Taoyuan Tiger Air flights from Cebu to Taipei Taoyuan
Manila Ninoy Aquino to Taipei Taoyuan Tiger Air flights from Manila Ninoy Aquino to Taipei Taoyuan
Taipei Taoyuan to Manila Ninoy Aquino Tiger Air flights from Taipei Taoyuan to Manila Ninoy Aquino
Taipei Taoyuan to Kalibo Tiger Air flights from Taipei Taoyuan to Kalibo
Kalibo to Taipei Taoyuan Tiger Air flights from Kalibo to Taipei Taoyuan
Cebu to Jakarta Tiger Air flights from Cebu to Jakarta
Jakarta to Cebu Tiger Air flights from Jakarta to Cebu
Cebu to Bali Denpasar Tiger Air flights from Cebu to Bali Denpasar
Bali Denpasar to Cebu Tiger Air flights from Bali Denpasar to Cebu
Jakarta to Taipei Taoyuan Tiger Air flights from Jakarta to Taipei Taoyuan
Taipei Taoyuan to Jakarta Tiger Air flights from Taipei Taoyuan to Jakarta


New Rules for Handbags

General Restrictions

In accordance with the new guidelines set by the International Civil Aviation Organization (ICAO) on tenteng bags, many countries have implemented restrictions on the transport of liquids, aerosols and gels in passenger tenteng bag.

The following Flight subject to the above rules:
  • Flights from Macau
  • Flights from Vietnam
  • Flights to and from Australia
  • Flights from China
  • Flights from Singapore
  • Flights from Thailand
  • Flight from Philippines
Examples liquids, aerosols and gels include:
  • All liquids, including drinks, soups and syrups
  • Gels, including hair gel and liquid soap
  • Pasta, including toothpaste
  • Creams, lotions and oils
  • The contents of aerosol cans, including spray, shaving cream, deodorant
  • Mascara
  • Mix the liquid-solid
  • Other items with similar dilution
    ** ** Note: Items above are common examples and not load it all.
Restrictions as follows:
  • Liquids, gels and aerosols will only be allowed in cabin baggage if placed in the bottle with the volume of each no more than 100 ml.
  • The bottle should be put in a clear plastic bag that could be reattached. The total volume of the bag must not exceed 1 liter.
  • Each person was allowed to bring a plastic bag only.
  • Bags may be removed from cabin baggage and handed over to the security guard for visual inspection.

Drugs and special dietary needs, including baby formula:

  • allowed in cabin baggage.
  • It may be removed from cabin baggage and shown to security personnel at the checkpoint. The item may have to undergo security checks.
  • Customers with prescription medicine are encouraged to bring along supporting documents (eg identity cards, letters from doctors) as verification.

Because some countries have imposed this restriction on flight arrival and departure, it could have an impact on your ability to carry duty-free purchases on board. Customers are encouraged to ask the attendant duty-free before buying.

The above items are examples of common and not load it all. Passengers can still bring the goods to the plane which is generally placed in the hand baggage, such as cameras, personal music devices, books and clothing. Existing limits for hand baggage remains the same. The following items will not be taken at the Tiger Airways flight anywhere and can not be carried in passenger baggage or hand baggage.

Rifle, Firearms and Weapons

Any object capable, or seems capable, removing bullets or cause injury, such as: All firearms (pistols, revolvers, shotguns, rifles, etc..) Imitation and imitation firearms, component parts of firearms (excluding telescopic device & shooting), air pistols, rifles and pellet guns. Igniter signal pistol, Pistol openers, all kinds of toy guns, rifle ball, bolt pistol and nail for the industry, crossbows, catapults, harpoon and fish waves gun, the murder weapon stars with euthanasia, tranquilizer or stun device, such as an awl livestock, energy weapons guided ballistic (laser), lighters shaped like a firearm.

Explosive substances and Burned

Any explosive substances or flammable that could pose a health risk passengers and crew or the security / safety of aircraft or property, including: ammunition, explosives, detonators and fuse fuel, explosives and explosive devices, replica or imitation explosive material, mines & other military goods, all types of grenades. gases & gas bottle, eg butane, propane, aketilana, oxygen - in large volume, fireworks, which can be lit with various forms of firecrackers and other items (including firecrackers party and toy caps), unsafe lighters, smoke generated from where tobacco or shell casings, fuel flammable liquid, such as gasoline, diesel fuel, lighter fluid, alcohol, ethanol, aerosol spray paint, turpentine & paint thinner, alcoholic beverages whose content exceeds 70% (140% proof).

Chemicals and Toxic Substances

Chemicals or toxins whatever posing a risk to the health of passengers and crew or the security / safety of aircraft or property, including: acid and alkali, eg battery "wet" easily spilled, causing rust or bleaching substances - eg mercury, chlorine, spray paralyze or weaken - eg mace, pepper spray, tear gas, radioactive materials - eg, drugs or commercial isotopes, toxins, hazardous substances or infectious biological material - eg infected blood, bacteria and viruses, material capable of producing fire or sudden burning, fire (except those authorized by fire protocols and aircraft emergency equipment).

Cabin Baggage

Passengers who are travelling on (TR) Tigerair Singapore and (IT) Tigerair Taiwan operated flights are allowed 2 pieces of carry-on luggage provided that each item does not exceed the dimensions of 54 cm x 38 cm x 23 cm, with a combined weight of 10kg.

Passengers are allowed to bring a laptop for free but will only be accepted on the basis of 'limited release' (ie, all 'risk borne passengers' for damage or delay). You might want to make sure that you have suitable private insurance for these items.

Sports Equipment

All sports equipment, including but not limited to golf clubs, skis, surfboards, bicycles and musical instruments will be accepted for travel if there is still space left and is charged S $ 30 or A $ 60 (or local currency with the same value) per item, per flight. Such goods are accepted for carriage by Tiger Airways passengers are entirely at risk.

Bicycles - bicycle must be packaged in bicycle box or bag, only one cycle per box or bag is allowed, tires must be deflated, handle the steering wheel must be aligned with the frame and pedals removed or aligned with the frame.
Firearms and ammunition are not accepted for carriage.


Equipment that will be taken as carry-on baggage must not exceed the size of 30 x 117 x 38 cm. Equipment in this category includes models trumpet horn, clarinet, flute, piccolo, trumpet, violin or viola and will form part of your free cabin baggage allowance. Such goods are accepted for carriage by Tiger Airways passengers are entirely at risk.
Any equipment that exceeds the size of the above must be registered to be included aircraft luggage space or seating can be ordered and are charged accordingly.

Live Animal Transportation

Transport of live animals, including pets, insects, reptiles or any animals, aircraft and items in the cabin is strictly prohibited for any reason.
Guide Dog accepted for travel on Domestic Flights in Australia. Please hubungipusat our information for more information.

The bodies of Transportation

Tiger Airways does not accept the body to be transported to any service.


Passengers are not allowed to bring the following items into the security restricted area and the cabin of the aircraft but could be contained in checked baggage if local regulations permit the importation of goods into the country:

Weapon pointy & Sharps

Pointed object or have blades that are capable of causing injury, including: axes, arrows and darts, iron footwear ice (solid steel, bent iron, or plate with iron spikes used in climbing), harpoons, ice axes & ice irons, ice skates, blades are easily locked or flicked with long blades, knives, including ceremonial knives, religious and hunting, made of metal or other material that is strong enough to be used as a potential weapon, meat cleaver, machete, razor and eye blades are open (except safety razors and blades in the cartridge), curved sword, sword and cane swords, scalpels, scissors with blades of any size, skis and poles for walking / climbing, throwing weapons, potentially building tool to be used as a pointed or sharp weapon, eg drills and drill bits, box cutters, multipurpose knives, all saws, screwdrivers, crowbars, hammers, pliers, wrenches / spanners, blow torches.

Blunt Instrument

Whatever blunt instrument that can cause injury, including tennis racket, baseball bat and a softball bat or bet - hard or elastic - ie police batons, police batons (sticks wrapped in leather with elastic shaft), batons and bats, bat cricket, golf clubs, hockey sticks and throwing sticks, sticks rounders, kayaks and pedal boats, skateboards, billiard, snooker sticks, fishing rods, martial arts equipment, eg knuckle duster, a stick, cosh, whip, nun-chucks, kubaton, kubasaunt.


1. Counter check-in

Check-in counters open 2 (two) hours before departure and closes 45 minutes before departure, except in India where they open a three (3) hours prior and closes 1 (one) hour prior to departure. If you arrive late, you will not be able to get on a plane and have to buy a new ticket.

If you buy Flight Combo, you must go through checks and immigration pabeaan applicable, then ask the baggage claim after the first flight, then check in again for your second flight. You will need at least 2 (two) hours to complete this process.

You must be at the departure gate at least 30 minutes before departure. Departure gate was closed about 15 minutes before departure. Passengers who arrive late at the departure gate will not be allowed to board the plane, their bags will be unloaded from the plane and no compensation will be given. If you wish to travel on the next flight, you have to buy a new ticket at the applicable rate.

2. Web check-in

Web Check-in is available from 48 hours (2 days) until 4 hours before the scheduled departure of your flight.

You need to print Web Check-in Boarding Pass and bring it with you to the airport to board the plane. Do not worry if you can not access the printer now. You can complete the Web Check-in process first and then go back to the Web Check-in page again later to print your Boarding Pass.

Call Centre

English Language Support

Singapore local time

+65 3157 6434
3157 6434 (dialing within Singapore)
5am to 10pm daily

Philippines local time

+63 2 798 4499
5am to 10pm daily

Sydney/ Melbourne local time

+61 2 8073 3421
+61 3 9034 3733
02 8073 3421 (dialing within Australia)
03 9034 3733 (dialing within Australia)
7am to 12am daily

Chinese Language Support

Singapore local time

+65 3157 6434
3157 6434 (dialing within Singapore)
9am to 9pm daily

China local time

+86 4008 428 268
9am to 9pm daily

Hong Kong local time

+852 3018 6899
9am to 9pm daily

Taiwan local time

+886 2 5599 2555
02 5599 2555 (dialing within Taiwan)
9am to 9pm daily

Bahasa Melayu Language Support

Malaysia local time

001 800 81 6756
Monday to Friday 9am to 6pm

Bahasa Indonesia Language Support

Indonesia Local Time / WIB

+62 21 29532888
9am – 6pm daily

Tamil Language Support

(India local time)

000 800 852 1400
Monday to Friday 9am to 6pm

Thai Language Support

Thailand local time

001 800 852 7146
Monday to Friday 9am to 6pm

Vietnamese Language Support

Vietnam local time

180 09242
Monday to Friday 9am to 6pm

Fare Rules

Tax and Other Fees

It is part of the total ticket price than the base rate paid per passenger. This fee is calculated by reference to the applicable government taxes and airport fees are paid Tiger Airways passenger flight related to certain routes along with administrative costs and others imposed by the airline.
Government taxes - It is the government arrival and departure taxes collected by the airlines and paid to the relevant government authorities. These taxes vary in each country and in some places is due upon departure and not by the airline.
Passenger Service Fee - This fee is charged to airlines airport authority for the use of terminal, runway, emergency services, security facilities, etc.. GST or VAT is currently levied at 0% on the ticket or the cost of related international flight. Domestic flight to Australia, GST applies. Note that all costs in A $ in the Help section already includes GST for Domestic Flights in Australia, while all costs in S $ without GST for Flight International. This number is only for guidance and we reserve the right to change it at any time.

Tickets regulations

  • TR flight operated by Tiger Airways Singapore.
  • TT flight operated by Tiger Airways Australia.

All Tiger Airways reservations must be made four (4) hours before the scheduled departure.
Fee listed is the cost per person per one-way flight.
Tiger Airways does not offer open date tickets or ticket open. Tickets are valid for one (1) year from the date of ticket issuance.
Prices listed do not include airport taxes and other applicable charges, unless already included in the ticket price for Australian Domestic Flight, you have responsibilities. All ticket prices can change unless already purchased and all seats are subject to availability.
Ticket prices, taxes and other costs can vary depending on currency exchange rates and will be shown as a reservation fee. Tiger Airways ticket prices and other costs can not be refunded except as stated in these Terms of Flight.
Date, time, and flights can be changed up to four (4) hours before the scheduled departure and are charged a change and the difference in ticket prices apply to those already paid.

Change of name changes allowed with costs S $ 60 or A $ 60 per passenger per flight sector plus the difference in ticket prices at the time of replacement and is only available through the Information Center at least 4 hours before the scheduled departure. Please note, there is no refund if the ticket price is cheaper at the time of the change.
If reservation is not changed at least four (4) hours prior to scheduled departure, all money associated reservation will be lost.
Infants under the age of two (2) years at the time of traveling, that does not occupy a seat aircraft only charge S $ 50 (or local currency with the same value) or $ 30 (for the Australian domestic flights) per infant per one-way flight . Babies are not required to pay taxes and other fees, and not get baggage allowance, passengers who paid adult ticket can choose the appropriate Luggage Upsize if necessary. Adult passengers aged over 18 years should only be allowed to travel with a baby.
Children over the age of two (2) years at the time of travel should occupy the seat plane. They have to pay the full ticket price, taxes and other costs.
All passengers who buy Combination Flight must undergo customs and immigration checks that apply and take the luggage and check in again for the next flight. Note, it takes a minimum of three (3) hours to complete this process.
Changes can not be made on the trip was through a combination of cost once the first flight.
All travel is subject to the provisions Airlines flight.
Stopover is not permitted on a combination of flight. Stopover is defined as the period was in the city and / or country change over a 24-hour flight.
S combination of parts that are not used can not be refunded or transferred.

Refund and Cancellation

Tiger Airways does not have a refund policy so it can not return the ticket money (fees and other costs) if the passenger decides it no longer requires a flight or can not travel due to changes in personal circumstances, including but not limited to medical reasons. Individual or Personal Travel Insurance is recommended for all passengers to cover the cancellation.
If a passenger decides no longer require flight, they are entitled to ask for a refund on the cost of Government Tax and Passenger Services other government taxes that have been paid. However, Tiger Airways will impose administrative costs S $ 50.00 or A $ 50.00 (for Australian domestic flights) (or local currency equivalent value) per passenger per sector to cover the cost of processing and bank fees for any tax refund request .
If a passenger died before the scheduled departure of their flight, Tiger Airways will refund a reservation after receiving a copy of the death certificate.

Change booking

All reservations on Tiger Airways could be changed based on the following conditions.

Flights Domestic / International

Date, time, and flights can be changed depending on the availability and pay the change fee per flight sector, per person, plus an additional cost of the difference between the total initial costs will be paid and the lowest total cost available for a new flight at the time the change is made. If the total cost of the new flight is lower, no refunds. Changes, subject to availability, can be done up to four (4) hours prior to the scheduled departure at www.tigerairways.com or Tiger Airways information center (based on hours of work center). Change is not confirmed before the new itinerary given to you.
Reservation changes can not be made within four (4) hours of the scheduled departure time earlier and / or AFTER one (1) year from date of purchase.

There are four ways to change your orders:

  • Directly, using the Tiger Airways website at www.tigerairways.com.
  • Through a special information center Tiger Airways - see section "Doing booking" for more details.
  • Tickets at the counters in Singapore, Phuket, Clark, Macau, Perth, Ho Chi Minh City, Guangzhou, Haikou, Shenzhen, Padang, Kuala Lumpur and all the domestic Australian
  • Through local travel agents who participated.
    Changes may not be allowed on certain promotional fares.

Flight cancellations and schedule changes

If your Tiger Airways flight was canceled, we will reschedule the next Tiger Airways flights available, free of charge.
Tiger Airways does not compensate, reimburse or provide other airline travel tickets and is not responsible for cancellation if it makes you miss the connecting flight.

If your flight is rescheduled before the flight, and left four hours before or after the initial departure time, then you will be entitled to a travel credit or full refund of the unused portion reservation if the flight is not offered suitable alternative and you do not want to go. This applies if you tell Tiger Airways more than four (4) hours prior to your flight departure schedule.

All passengers should ensure that they have a personal travel insurance protection in force to cover this possibility.
Passengers who book at the beginning should check the flight time away / home between 24 and 72 hours prior to departure by using the "View / edit / resend travel plans" on the web site or by contacting Tiger Airways Tiger Airways information center.

Reservation changes will be notified via email. Passengers are responsible for ensuring that the email address given is active and frequently accessed. Tiger Airways is not responsible for the email change on the reservation that can not be accessed.
In the event of flight delays or schedule changes suddenly, where a delay or schedule change is less than four (4) hours, Tiger Airways will not give a warning to the passengers first. To delay for a particular purpose or change the schedule more than four (4) hours, all efforts will be taken to contact passengers via the phone number or email address provided at the time of reservation.

Standby and Wait List

Tiger Airways policy does not idle or waiting list. All reservations must be confirmed a minimum of four (4) hours before the schedule departure.

Flights Canal

Tiger Airways are the airlines 'point-to-point' is very tight. We also do not offer and could not facilitate, the transfer of passengers or their baggage to other flights, whether operated by Tiger Airways or other airlines.
All freight train or bus transfer listed www.tigerairways.com or promoted by Tiger Airways operated separately from airlines and flight canal can not be guaranteed.
Tiger Airways is not responsible for the information transfer is delayed, canceled or wrong.
All passengers have to undergo the Immigration / Customs in force and took their luggage after their arrival flying Tiger Airways. Transfer using the airport facilities ('Airside') is not permitted.


Tiger Airways Flight was formed on December 12, 2003 and began selling tickets on August 31, 2004. Airlines started operations in a difficult environment sloping aviation industry due to soaring oil prices and strong competition from other airlines. Tiger Airways suspend its plans to charge additional oil as was done by the competitors.
On 21 September 2005, the company reported that for the first year of operation, there are over 50,000 passengers use the tiger flight, flight 5000 which followed the schedule, and the perfect flight levels by 98.7%. 94% cost and 90% are innocent who came last flight schedules follow. Tiger Airways also has purchased four planes and flights to 9 cities opening goal.
This cost will increase its fleet to nine Airbus A320 aircraft in late 2006, and to serve at least 3 million passengers every year at that time. Tiger Airways is also hoping to add another six destinations in 2006, including to China and India.
Tiger Airways is the first low-cost airline from Singapore who received graduation from the Chinese government to fly to various cities in southern China such as Haikou, Guangzhou and Shenzhen in an announcement on February 21, 2006. Ticket sales to various cities began on February 24, 2006, with the first flight to Shenzhen on April 15, Haikou and Guangzhou on April 26 on 27 April 2006. Tiger Airways have flights to various cities are very popular and have increased the number of flights to Haikou and Guangzhou less than three months after its maiden voyage.

Company Profile

Travel isn't just about occupying an incredible flight at an awesome rate – its also about being secured and educated when you book on the web. Whether you are flying Tiger Airways Singapore local flights or international courses, airpaz.com will help you with your tiger air online booking, send you flight updates, and give you all the information you need for the your flight. We want you to be happy and enjoy the flight.

Find the most popular flights for Tiger Airway Singapore service to big cities and destinations everywhere throughout the world with our low price for promo Tigerair. Use Airpaz to book to global destinations Tigerair Singapore flights to help arrange a business trip or the get-away of a lifetime. We will help you find the tiger airlines promo fare.

Tigerair, built up in 2004, is a Singapore-based budget plan flight that offers reasonable travel choices and a consistent client experience.

With an armada of Airbus A320-family air ship, averaging around three years old, the Group works flights to more than 50 destinations over 14 nations in Asia/Australia.


Code City Airport Name Terminal Info
ADL Adelaide Adelaide International Airport Terminal 1
BDO Bandung Husein Sastranegara International Airport
BKK Bangkok Suvarnabhumi Airport (New Bangkok International Airport) International Terminal (Check-in Row : L06, L02, L01, L03, L05, L04 )
BLR Bangalore Bengaluru International Airport International Terminal
BNE Brisbane Brisbane Airport Domestic Terminal
CAN Guangzhou Guangzhou Baiyun International Airport Terminal 1
CEB Cebu Mactan-Cebu International Airport International Terminal (TR flights) / Domestic Terminal (DG flights)
CFS Coffs Harbour Coffs Habrbour Airport
CGK Jakarta Jakarta International Airport (Soekarno-Hatta) Terminal 2
CNS Cairns Cairns International Airport Domestic Terminal 2
COK Kochi Cochin International Airport (Nedumbassery Airport) International Terminal
CRK Clark (Manila) Diosdado Macapagal (Clark) International Airport Terminal 1
DAC Dhaka Shahjalal International Airport Terminal 1
DPS Bali Ngurah Rai International Airport International Terminal
DRW Darwin Darwin International Airport
HAK Haikou Haikou Meilan International Airport International Terminal
HAN Hanoi Noi Bai International Airport Lobby B
HBA Hobart Hobart Airport
HDY Hat Yai Hat Yai International Airport International Terminal
HKG Hong Kong Hong Kong International Airport Terminal 2
HKT Phuket Phuket International Airport Terminal 2
HYD Hyderabad Rajiv Gandhi International Airport International Terminal
KBV Krabi Krabi Airport Terminal 1
KLO Kalibo (Boracay) Kalibo International Airport
KUL Kuala Lumpur Kuala Lumpur International Airport Kuala Lumpur International Airport 2 (KLIA2)
LGK Langkawi Langkawi International Airport
LJG Lijiang City Lijiang Sanyi Airport
MAA Chennai Chennai International Airport Anna Terminal (International Terminal)
MCY Sunshine Coast Sunshine Coast Airport
MEL Melbourne Melbourne Airport Tullamarine Domestic Terminal 4
MFM Macau Macau International Airport International Terminal
MKY Mackay-Whitsundays Mackay Airport
MLE Male Ibrahim Nasir International Airport
MNL Manila (NAIA) Ninoy Aquino International Airport Terminal 1
NGB Ningbo Ningbo Lishe International Airport
OOL Gold Coast Gold Coast Airport Terminal 1
PEN Penang Penang International Airport International Terminal
PER Perth Perth Airport Terminal 1 (TR flights) / Terminal 2 (TT flights)
PNH Phnom Penh Phnom Penh International Airport International Terminal
PPP Whitsunday Coast Proserpine (Whitsunday Coast) Airport
RGN Yangon Yangon International Airport International Terminal
SGN Ho Chi Minh City Tan Son Nhat International Airport Terminal 2
SIN Singapore Changi International Airport Terminal 2
SUB Surabaya Juanda International Airport DomesticTerminal
SYD Sydney Terminal 2
SZX Shenzhen Shenzhen Bao'an International Airport Terminal D
TPE Taipei Taiwan Taoyuan International Airport Terminal 1
TRV Thiruvananthapuram Trivandrum International Airport International Terminal
TRZ Tiruchirapalli (Trichy) Tiruchirapalli international Airport International Terminal
XIY Xi'an Xi'an Xianyang International Airport Terminal 2

Term and Condition

Terms and Conditions