Cheap flights from Dulles Intl (IAD) to Vancouver from $159

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 8/27. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
IAD — YVR
Jun 11 — Jun 181

The best prices from Washington, D.C. Dulles Intl to Vancouver are usually found in May or November, booked 23 days in advance, depart on a Tuesday or Monday and return on a Monday

Cheap flight deals from Dulles Intl to Vancouver

Discover tips and strategies to find the most affordable flight options for your journey from Dulles Intl (IAD) to Vancouver (8CA). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated June 6, 2024.

Popular in

February

Cheapest in

May

Round-trip from

$240

One-way from

$176
High demand for flights, 18% potential price rise
Best time to find cheap flights, 32% potential price drop
From Washington, D.C. Dulles Intl to Vancouver
One-way flight from Washington, D.C. Dulles Intl to Vancouver

What is the cheapest day to fly round-trip from Washington, D.C. Dulles Intl Airport to Vancouver?

Wednesday flights are found to be more expensive to fly from Washington, D.C. Dulles Intl Airport to Vancouver. This shouldn’t discourage you from searching, as you can still find great deals by being flexible with your options. Use our search form to find deals on tickets to Vancouver.

How far in advance should I book a flight from Washington, D.C. Dulles Intl Airport to Vancouver?

Users have found that booking a flight from Washington, D.C. Dulles Intl Airport to Vancouver at least 42 days early can save you up to 41% on average compared to booking a flight this week. If booking 42 days before your flight isn’t an option for you, users have found flights from Washington, D.C. Dulles Intl Airport to Vancouver for as little as $412 when booking for a departure date within the next two weeks. You can also check prices now. Some users have found airline tickets as low as $625 for flights departing within the next 3 days.

What is the cheapest month to fly from Washington, D.C. Dulles Intl Airport to Vancouver?

Due to multiple factors, expect to potentially pay more when booking in March. For low rates, April can be a great choice for travel to Vancouver. Flights to Vancouver from Washington, D.C. Dulles Intl Airport in April are about $507 on average during April, but can be found for as low as $163.

What is the cheapest time of day to fly from IAD to YVR?

It’s optimal to fly from Washington, D.C. Dulles Intl Airport to Vancouver in the evening. By choosing this option you can save up to 50% on the cost of your flight, compared to a flight in the afternoon.

Cheap Dulles Intl to Vancouver flights in June & July 2024

Find cheap flight options from Dulles Intl to Vancouver specifically for the months of June and July 2024. Explore affordable fares based on user searches. Over the last 7 days, Cheapflights users made 3,050,429 searches. Prices were last updated on June 6, 2024.
Listed are some of the best fares we've found on flights departing from Washington, D.C. to Vancouver in 2024. Check back in a little while for more flight options.
Thu 7/1112:07 pmIAD - YVR
2 stops32h 34mMultiple Airlines
Tue 7/167:35 pmYVR - IAD
1 stop9h 00mMultiple Airlines
Deal found 6/5$356
Thu 7/1112:07 pmIAD - YVR
1 stop13h 50mMultiple Airlines
Tue 7/167:35 pmYVR - IAD
1 stop9h 00mMultiple Airlines
Deal found 6/5$358
Thu 7/1112:07 pmIAD - YVR
1 stop13h 50mMultiple Airlines
Tue 7/1610:35 pmYVR - IAD
Nonstop5h 06mMultiple Airlines
Deal found 6/5$363
Tue 7/912:00 pmIAD - YVR
1 stop25h 56mSun Country Air
Sun 7/1411:59 pmYVR - IAD
1 stop7h 31mSun Country Air
Deal found 6/5$370
Tue 7/211:50 amIAD - YVR
1 stop26h 02mSun Country Air
Sun 7/1411:59 pmYVR - IAD
1 stop7h 31mSun Country Air
Deal found 6/5$380
Mon 7/295:45 pmIAD - YVR
Nonstop5h 48mAir Canada
Wed 8/710:35 pmYVR - IAD
Nonstop5h 06mAir Canada
Deal found 6/5$382
Fri 7/56:45 pmIAD - YVR
1 stop8h 10mMultiple Airlines
Fri 7/1212:00 pmYVR - IAD
2 stops21h 10mMultiple Airlines
Deal found 6/5$384
Thu 6/2012:16 pmIAD - YVR
1 stop28h 50mSun Country Air
Sun 6/3011:59 pmYVR - IAD
1 stop6h 45mSun Country Air
Deal found 6/5$390
Tue 7/165:36 pmIAD - YVR
1 stop8h 19mUnited Airlines
Tue 7/3010:35 pmYVR - IAD
Nonstop5h 06mUnited Airlines
Deal found 6/6$391

Dulles Intl to Vancouver 2024 flight deals

Discover exclusive flight deals for travel between Dulles Intl and Vancouver in 2024. Find excellent offers based on user searches. Over the last 7 days, Cheapflights users made 3,050,429 searches. Data last updated June 6, 2024.
Listed are some of the best fares we've found on flights departing from Washington, D.C. to Vancouver in 2024. Check back in a little while for more flight options.
Mon 8/126:45 pmIAD - YVR
1 stop8h 24mWestJet
Fri 8/237:00 amYVR - IAD
1 stop7h 46mWestJet
Deal found 6/5$355
Thu 7/1112:07 pmIAD - YVR
2 stops32h 34mMultiple Airlines
Tue 7/167:35 pmYVR - IAD
1 stop9h 00mMultiple Airlines
Deal found 6/5$356
Thu 7/1112:07 pmIAD - YVR
1 stop13h 50mMultiple Airlines
Tue 7/167:35 pmYVR - IAD
1 stop9h 00mMultiple Airlines
Deal found 6/5$358
Thu 7/1112:07 pmIAD - YVR
1 stop13h 50mMultiple Airlines
Tue 7/1610:35 pmYVR - IAD
Nonstop5h 06mMultiple Airlines
Deal found 6/5$363
Tue 7/912:00 pmIAD - YVR
1 stop25h 56mSun Country Air
Sun 7/1411:59 pmYVR - IAD
1 stop7h 31mSun Country Air
Deal found 6/5$370
Tue 7/211:50 amIAD - YVR
1 stop26h 02mSun Country Air
Sun 7/1411:59 pmYVR - IAD
1 stop7h 31mSun Country Air
Deal found 6/5$380
Mon 8/128:15 amIAD - YVR
Nonstop5h 40mUnited Airlines
Tue 8/1310:35 pmYVR - IAD
Nonstop5h 06mUnited Airlines
Deal found 6/4$382
Fri 7/56:45 pmIAD - YVR
1 stop8h 10mMultiple Airlines
Fri 7/1212:00 pmYVR - IAD
2 stops21h 10mMultiple Airlines
Deal found 6/5$384
Tue 8/209:09 amIAD - YVR
1 stop8h 59mAir Canada
Mon 8/2610:35 pmYVR - IAD
Nonstop5h 09mAir Canada
Deal found 6/4$387

Dulles Intl to Vancouver flights leaving soon

Find last-minute flight options from Dulles Intl to Vancouver for spontaneous travel. Discover available flights and compare prices based on user searches. Secure great deals and offers for spontaneous trips with quick booking options. Over the last 7 days, Cheapflights users made 3,050,429 searches. Data last updated June 6, 2024.
Have a look at some of the last-minute flights available departing from Washington, D.C. to Vancouver. Users should examine the flight details to ensure there are no surprises.
Tue 6/117:00 amIAD - YVR
1 stop8h 22mMultiple Airlines
Fri 6/147:00 amYVR - IAD
1 stop8h 04mMultiple Airlines
Deal found 6/6$409
Sat 6/158:26 amIAD - YVR
Nonstop5h 40mAir Canada
Wed 6/2610:35 pmYVR - IAD
Nonstop5h 06mAir Canada
Deal found 6/5$436
Tue 6/115:10 pmIAD - YVR
1 stop8h 45mUnited Airlines
Fri 6/1410:35 pmYVR - IAD
Nonstop5h 06mUnited Airlines
Deal found 6/6$445
Sat 6/158:26 amIAD - YVR
Nonstop5h 40mUnited Airlines
Wed 6/261:45 pmYVR - IAD
1 stop8h 02mUnited Airlines
Deal found 6/5$451
Sat 6/157:00 pmIAD - YVR
1 stop7h 59mAlaska Airlines
Mon 6/171:30 pmYVR - IAD
1 stop7h 29mAlaska Airlines
Deal found 6/6$454
Wed 6/129:28 amIAD - YVR
1 stop14h 41mAmerican Airlines
Wed 6/1910:04 pmYVR - IAD
1 stop7h 54mAmerican Airlines
Deal found 6/5$460
Wed 6/1211:16 amIAD - YVR
2 stops15h 45mMultiple Airlines
Wed 6/194:55 pmYVR - IAD
1 stop15h 42mMultiple Airlines
Deal found 6/5$473
Sat 6/158:26 amIAD - YVR
Nonstop5h 40mAir Canada
Fri 6/288:30 amYVR - IAD
Nonstop5h 15mAir Canada
Deal found 6/5$495
Sat 6/158:26 amIAD - YVR
Nonstop5h 40mUnited Airlines
Fri 6/283:20 pmYVR - IAD
1 stop11h 05mUnited Airlines
Deal found 6/5$510

One-way flights to Vancouver from Dulles Intl

Search for one-way flight options from Dulles Intl to Vancouver. Find affordable one-way fares based on user searches. Compare prices and availability to plan your one-way journey according to your preferred dates and budget. Over the last 7 days, Cheapflights users made 3,050,429 searches. Data last updated June 6, 2024.
Take a look at some of the best available options we've come across on one-way flights from Washington, D.C. to Vancouver. Users can also find round-trip Washington, D.C. to Vancouver flights by using the search form above.
Tue 8/277:09 pmIAD - YVR
1 stop7h 47mAlaska Airlines
Deal found 6/5$159
Tue 7/25:50 pmIAD - YVR
2 stops26h 51mMultiple Airlines
Deal found 6/4$162
Wed 7/1711:27 amIAD - YVR
2 stops32h 09mMultiple Airlines
Deal found 6/4$164
Sun 7/285:10 pmIAD - YVR
2 stops32h 55mMultiple Airlines
Deal found 6/5$170
Tue 7/238:15 amIAD - YVR
Nonstop5h 40mUnited Airlines
Deal found 6/4$171
Mon 7/110:37 amIAD - YVR
2 stops32h 59mMultiple Airlines
Deal found 6/4$175
Mon 7/155:07 pmIAD - YVR
1 stop9h 56mAir Canada
Deal found 6/4$176
Mon 8/196:30 amIAD - YVR
2 stops15h 33mUnited Airlines
Deal found 6/5$178
Tue 7/235:36 pmIAD - YVR
1 stop8h 19mUnited Airlines
Deal found 6/6$181

Find flights from Dulles Intl to Vancouver within your budget

Customize your flight search to find flights from Dulles Intl to Vancouver that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 3,050,429 searches. Data last updated June 6, 2024.

Fly from

Any airport

Fly to

Any airport

Budget

$355 - $508

Route

Depart

Return

Price

Washington, D.C. Dulles IntlVancouver Intl

IAD - YVR

IADYVR

Washington, D.C. Dulles Intl

Mon 8/12

1 stop8h 24m

Vancouver Intl

Fri 8/23

1 stop7h 46m

$355

Washington, D.C. Dulles IntlVancouver Intl

IAD - YVR

IADYVR

Washington, D.C. Dulles Intl

Thu 7/11

2 stops32h 34m

Vancouver Intl

Tue 7/16

1 stop9h 00m

$356

Washington, D.C. Dulles IntlVancouver Intl

IAD - YVR

IADYVR

Washington, D.C. Dulles Intl

Tue 7/9

1 stop25h 56m

Vancouver Intl

Sun 7/14

1 stop7h 31m

$370

Washington, D.C. Dulles IntlVancouver Intl

IAD - YVR

IADYVR

Washington, D.C. Dulles Intl

Mon 8/12

Nonstop5h 40m

Vancouver Intl

Tue 8/13

Nonstop5h 06m

$382

Washington, D.C. Dulles IntlVancouver Intl

IAD - YVR

IADYVR

Washington, D.C. Dulles Intl

Tue 8/20

1 stop8h 59m

Vancouver Intl

Mon 8/26

Nonstop5h 09m

$387

Washington, D.C. Dulles IntlVancouver Intl

IAD - YVR

IADYVR

Washington, D.C. Dulles Intl

Tue 9/3

1 stop8h 34m

Vancouver Intl

Wed 9/11

2 stops19h 33m

$469

Washington, D.C. Dulles IntlVancouver Intl

IAD - YVR

IADYVR

Washington, D.C. Dulles Intl

Wed 6/19

2 stops19h 28m

Vancouver Intl

Tue 6/25

1 stop22h 55m

$470

Washington, D.C. Dulles IntlVancouver Intl

IAD - YVR

IADYVR

Washington, D.C. Dulles Intl

Tue 7/9

1 stop11h 18m

Vancouver Intl

Thu 7/11

1 stop7h 15m

$482

Washington, D.C. Dulles IntlVancouver Intl

IAD - YVR

IADYVR

Washington, D.C. Dulles Intl

Wed 7/3

2 stops11h 28m

Vancouver Intl

Wed 7/10

1 stop16h 02m

$508

Flights are sorted by cheapest first

Deals found on 6/5

How far ahead should I book a flight from Washington, D.C. Dulles Intl Airport to Vancouver?

Use this chart to determine the optimal time to book a round-trip flight from Dulles Intl to Vancouver. Price data was last updated on May 31, 2024.
The best time to book flights from Washington, D.C. Dulles Intl Airport to Vancouver is 23 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.
Search Deals

What is the cheapest day to fly from Washington, D.C. Dulles Intl Airport to Vancouver?

Use this chart to determine the cheapest time to fly round-trip from Dulles Intl to Vancouver. Price data was last updated on June 2, 2024.
Morning
Noon
Afternoon
Evening
All times are departure.
Travelers seeking maximum savings on their Washington, D.C. Dulles Intl Airport to Vancouver flight should consider departing on Wednesday evenings when fares are most often at their lowest. Saturday at noon flights should be avoided if possible as fares are typically the most expensive at this time.
Search Deals

Best time to book a flight from Dulles Intl to Vancouver

Have a flexible travel schedule? Discover the best time to fly to Vancouver from Dulles Intl with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Temperature and rainfall in Vancouver by month

Plan your trip to Vancouver by taking into account the average temperature and rainfall totals by month.

YVR

Temperature

39.2 - 64.4 °F

If weather is an important factor for your trip to Vancouver, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 64.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 39.2 F).

Reviews of airlines servicing Vancouver

Get insights into the airlines that provide service to Vancouver. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Vancouver. Reviews last updated June 6, 2024.
Peruse reviews from past customers who have flown with Sun Country Air, United Airlines and Air Canada from Washington, D.C. to Vancouver to help guide your decision. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
8.1
Very good
9,222 reviews

Entertainment

7.3

Boarding

8.2

Food

7.3

Crew

8.6

Overall

8.1

Comfort

7.9

Reviews

1 / 10

Crew and airport staff were excellent. They accommodated my needs and were super professional and kind.

8.1
Very good
9,222 reviews
8.1
Very good
9,222 reviews

Entertainment

7.3

Boarding

8.2

Food

7.3

Crew

8.6

Overall

8.1

Comfort

7.9

Reviews

1 / 10

Crew and airport staff were excellent. They accommodated my needs and were super professional and kind.

8.0
Very good
10,368 reviews
8.1
Very good
9,222 reviews

Entertainment

7.3

Boarding

8.2

Food

7.3

Crew

8.6

Overall

8.1

Comfort

7.9

Reviews

1 / 10

Crew and airport staff were excellent. They accommodated my needs and were super professional and kind.

7.5
Good
2,856 reviews
8.1
Very good
9,222 reviews

Entertainment

7.3

Boarding

8.2

Food

7.3

Crew

8.6

Overall

8.1

Comfort

7.9

Reviews

1 / 10

Crew and airport staff were excellent. They accommodated my needs and were super professional and kind.

7.4
Good
382 reviews
8.1
Very good
9,222 reviews

Entertainment

7.3

Boarding

8.2

Food

7.3

Crew

8.6

Overall

8.1

Comfort

7.9

Reviews

1 / 10

Crew and airport staff were excellent. They accommodated my needs and were super professional and kind.

7.4
Good
10,696 reviews
8.1
Very good
9,222 reviews

Entertainment

7.3

Boarding

8.2

Food

7.3

Crew

8.6

Overall

8.1

Comfort

7.9

Reviews

1 / 10

Crew and airport staff were excellent. They accommodated my needs and were super professional and kind.

Related info for your journey

Find useful and relevant information for your journey from Dulles Intl to Vancouver. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
  • Can I find flights from Washington, D.C. Dulles Intl Airport to Vancouver for under $400 on Cheapflights?

    Yes, there are multiple flights from Washington, D.C. Dulles Intl Airport to Vancouver for under $400. The cheapest flight booked recently is on WestJet for just $355, but on average you can expect to pay $385.

  • Are there nonstop flights from Washington, D.C. Dulles Intl Airport to Vancouver for under $400 on Cheapflights?

    Cheapflights has at least 20 direct flights from Washington, D.C. Dulles Intl Airport to Vancouver under $400. A good price for a nonstop flight from Washington, D.C. Dulles Intl Airport to Vancouver is less than $469.

  • Are there last-minute flights available from Washington, D.C. Dulles Intl Airport to Vancouver for under $500?

    There are currently 20+ open flights from Washington, D.C. Dulles Intl Airport to Vancouver within the next 7 days for less than $500.

  • What are the cheapest airlines flying from Washington, D.C. Dulles Intl Airport to Vancouver round-trip?

    WestJet, at $355, was found to be the cheapest airline from Washington, D.C. Dulles Intl Airport to Vancouver.Alternate airlines to your destination round-trip include Sun Country Air and United Airlines. WestJet is currently priced 25% below the average price you’ll pay for this route.

  • What are the cheapest airlines to fly from Washington, D.C. Dulles Intl Airport to Vancouver one-way?

    One-way options have recently been found by users for as low as $159 on Alaska Airlines. Other airlines that offer cheap prices include United Airlines from $171 and Air Canada from $176 one-way.

  • What are the cheapest flights from Washington, D.C. Dulles Intl Airport to Vancouver?

    Looking at all options, your cheapest flight can be booked for $160. While the most popular route (Washington, D.C. Dulles Intl - Vancouver Intl) can be booked for $359 on average our data indicates $877 when flying from Washington, D.C. Dulles Intl Airport to Vancouver.

  • What does IAD to YVR mean?

    IAD stands for Washington, D.C. Dulles Intl Airport, while YVR stands for Vancouver Intl Airport. These codes are often called IATA codes, a set of identifiers established by IATA (International Air Transport Association) that is widely used by airlines and the aviation industry. While you’re still figuring out your travel plans, it’s not a bad idea to learn the names and codes of other airports around these areas: Vancouver Coal Harbour Airport (CXH), Ganges SPB Airport (YGG), Galiano Island Montagne Harbor Airport (YMF), Village Bay Miners Bay Airport (YAV), Saturna Island Lyall Harbour Airport (YAJ).

  • Can I find deals for flights from Dulles Intl to Vancouver that include extra baggage allowance?

    The amount of baggage you can bring on your Dulles Intl to Vancouver flight depends on the airline and the type of fare you've chosen. After entering your flight details, you'll be able to view the specific baggage policies for each deal in the search results. Keep in mind that certain deals may offer additional baggage allowance.

  • Can I find deals on flights from Dulles Intl to Vancouver with specific airlines?

    Yes, Cheapflights allows you to browse and filter Dulles Intl to Vancouver flight deals by airline. After entering your origin and destination, use the available filters to view flights offered by airlines.

  • Can I find deals for flights from Dulles Intl to Vancouver that include hotel bookings?

    Yes. In addition to deals on Dulles Intl to Vancouver flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Dulles Intl to Vancouver?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Dulles Intl to Vancouver.

  • Can I find deals for business class flights from Dulles Intl to Vancouver?

    Yes. Cheapflights offers flight deals from Dulles Intl to Vancouver by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • Can I find deals for flights from Dulles Intl to Vancouver that allow pets onboard?

    Many airlines flying from Dulles Intl to Vancouver offer the option to travel with pets. After selecting a flight deal, you can find more information about the airline's pet policy on their official website or by contacting the airline directly. Please note that additional fees and restrictions may apply.

  • Can I find deals on last-minute flights from Dulles Intl to Vancouver?

    Yes, you can often find last-minute deals on Dulles Intl to Vancouver flights on Cheapflights. However, these deals can vary and may not always be available. We recommend checking back frequently or signing up for price alerts for the most up-to-date deals.

  • How recently were the Washington, D.C. Dulles Intl Airport to Vancouver flight deals updated?

    The Washington, D.C. Dulles Intl Airport to Vancouver flight deals you see on this page were last updated on 6/5.

  • What are the most popular airlines that fly from Washington, D.C. Dulles Intl Airport to Vancouver?

  • What is the cheapest month to book a flight from Washington, D.C. Dulles Intl Airport to Vancouver?

    Currently, October is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to Vancouver (average of $240). Flying from Washington, D.C. Dulles Intl Airport to Vancouver in July is currently the most expensive (average of $447). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Top 6 airlines flying from Dulles Intl to Vancouver

Discover the top 6 airlines that operate flights from Dulles Intl to Vancouver. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 3,050,429 searches. Data last updated June 6, 2024.
AirlineCheapestAverageFlexibilityOn-time
Air CanadaCheapest$165Average$380FlexibilityNo cancel feeOn-time67%
United AirlinesCheapest$221Average$577FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$249Average$585FlexibilityNo cancel feeOn-time75%
WestJetCheapest$309Average$549FlexibilityNo cancel feeOn-time60%
DeltaCheapest$392Average$541FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$489Average$543FlexibilityNo cancel feeOn-time71%

Search flights from Dulles Intl to Vancouver by cabin class

Find flights from Dulles Intl to Vancouver, based on your preferred cabin class, be it economy, premium economy, business, or first class.

Hourly flight availability from Dulles Intl to Vancouver

Find hourly flight availability from Dulles Intl to Vancouver. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 6, 2024.
1%of flight departuresEarly morningMidnight to 6 am
71%of flight departuresMorning6 am to noon
28%of flight departuresAfternoonNoon to 6 pm
0%of flight departuresEvening6 pm to midnight
Midnight
6 AM
Noon
6 PM
100% Free
Cheapflights is completely free to use, so you can start saving the moment you arrive.
Book with Flexibility
Our users can plan ahead with confidence and find flights with no change fees
Travel Smart
Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.