Cheap flights from Texas to Birmingham (BHX) from $247

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 9/12. 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.
DFW — BHX
Jun 2 — Jun 91

What is the cheapest month to fly from Texas to Birmingham?

The best pricing can be found in the month of December. Prices to Birmingham from Texas average $1,039. You can even find prices in December for less than $1,039, as users have found deals to Birmingham from as low as $576. The month of July appears to be one of the more expensive times to travel to Birmingham from Texas. Flying in the targeted month can save you up to 46%.

When is the cheapest time to fly from Texas to Birmingham (TX - BHX)?

When flying from Texas to Birmingham, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Cheap Air France flights from Texas to Birmingham

Explore cheap flight options specifically provided by Air France for the route between Texas and Birmingham. Find affordable fares and compare prices with other airlines to secure the best deal for your journey. Over the last 7 days, Cheapflights users made 2,696,634 searches. Data last updated May 28, 2024.
Take a peek at the cheapest Air France flights we've detected traveling from Texas to Birmingham. Make sure to double check the flight details before booking.
Thu 7/183:45 pmDFW - BHX
1 stop11h 50mAir France
Fri 1/106:00 amBHX - DFW
1 stop13h 45mAir France
Deal found 5/28$737
Mon 9/93:45 pmDFW - BHX
1 stop11h 50mAir France
Wed 1/296:15 pmBHX - DFW
1 stop25h 30mAir France
Deal found 5/28$749
Mon 7/83:45 pmDFW - BHX
1 stop15h 20mAir France
Fri 12/66:00 amBHX - DFW
1 stop13h 45mAir France
Deal found 5/27$761
Mon 7/153:45 pmDFW - BHX
1 stop11h 50mAir France
Fri 1/106:00 amBHX - DFW
1 stop13h 45mAir France
Deal found 5/28$762
Sat 9/712:30 pmDFW - BHX
2 stops15h 05mAir France
Wed 1/296:15 pmBHX - DFW
1 stop25h 30mAir France
Deal found 5/28$804
Tue 9/103:45 pmDFW - BHX
1 stop11h 50mAir France
Wed 1/296:15 pmBHX - DFW
1 stop25h 30mAir France
Deal found 5/28$841
Wed 9/113:35 pmDFW - BHX
2 stops15h 30mAir France
Wed 1/296:15 pmBHX - DFW
1 stop25h 30mAir France
Deal found 5/28$846
Mon 7/82:12 pmDAL - BHX
2 stops26h 03mAir France
Fri 12/611:00 amBHX - DAL
2 stops36h 07mAir France
Deal found 5/27$883
Fri 9/63:45 pmDFW - BHX
1 stop11h 50mAir France
Wed 1/296:15 pmBHX - DFW
1 stop25h 30mAir France
Deal found 5/28$983

Cheap Delta flights from Texas to Birmingham

Explore cheap flight options specifically provided by Delta for the route between Texas and Birmingham. Find affordable fares and compare prices with other airlines to secure the best deal for your journey. Over the last 7 days, Cheapflights users made 2,696,634 searches. Data last updated May 28, 2024.
Take a gander at the lowest prices we've found on Delta flights from Texas to Birmingham. Check back soon if you're not seeing flights that suit your needs.
Fri 10/43:50 pmIAH - BHX
1 stop18h 55mDelta
Tue 10/86:15 amBHX - IAH
1 stop13h 20mDelta
Deal found 5/28$714
Fri 10/411:30 amIAH - BHX
2 stops16h 05mDelta
Tue 10/86:15 amBHX - IAH
1 stop13h 20mDelta
Deal found 5/28$718
Fri 10/411:30 amIAH - BHX
2 stops16h 05mDelta
Tue 10/810:30 amBHX - IAH
2 stops19h 29mDelta
Deal found 5/28$728
Mon 9/93:45 pmDFW - BHX
1 stop19h 00mDelta
Fri 1/316:00 amBHX - DFW
1 stop13h 45mDelta
Deal found 5/28$738
Sun 9/83:23 pmDFW - BHX
2 stops15h 42mDelta
Fri 1/316:00 amBHX - DFW
1 stop13h 45mDelta
Deal found 5/28$742
Mon 9/93:45 pmDFW - BHX
1 stop19h 00mDelta
Wed 1/2911:00 amBHX - DFW
2 stops17h 59mDelta
Deal found 5/28$748
Mon 9/912:01 pmDAL - BHX
2 stops15h 34mDelta
Wed 1/296:00 amBHX - DAL
2 stops20h 40mDelta
Deal found 5/28$752
Tue 9/1012:01 pmDAL - BHX
2 stops15h 34mDelta
Fri 1/316:00 amBHX - DAL
2 stops17h 55mDelta
Deal found 5/28$753
Mon 9/92:50 pmDAL - BHX
2 stops16h 15mDelta
Thu 1/301:30 pmBHX - DAL
2 stops16h 14mDelta
Deal found 5/28$755

Cheap Texas to Birmingham flights in May & June 2024

Find cheap flight options from Texas to Birmingham specifically for the months of May and June 2024. Explore affordable fares based on user searches. Over the last 7 days, Cheapflights users made 2,696,634 searches. Prices were last updated on May 28, 2024.
Scroll through some of the best deals on flights from Texas to Birmingham in 2024. Check back in a little while for more flight options.
Mon 6/249:39 amIAH - BHX
2 stops16h 01mAmerican Airlines
Wed 8/78:15 amBHX - IAH
2 stops17h 24mAmerican Airlines
Deal found 5/27$986
Tue 6/116:20 pmDFW - BHX
2 stops35h 55mMultiple Airlines
Mon 6/179:05 amBHX - DFW
2 stops31h 54mMultiple Airlines
Deal found 5/28$1,071
Sun 6/212:15 pmIAH - BHX
2 stops23h 45mMultiple Airlines
Wed 6/125:40 pmBHX - IAH
3 stops25h 55mMultiple Airlines
Deal found 5/28$1,090
Wed 6/127:30 amDFW - BHX
2 stops19h 00mUnited Airlines
Sun 6/165:55 amBHX - DFW
2 stops21h 53mUnited Airlines
Deal found 5/28$1,111
Tue 6/113:45 pmDFW - BHX
1 stop19h 00mDelta
Sun 6/166:15 amBHX - DFW
1 stop13h 30mDelta
Deal found 5/28$1,118
Tue 6/113:30 pmDFW - BHX
2 stops15h 35mDelta
Sun 6/166:15 amBHX - DFW
1 stop13h 30mDelta
Deal found 5/28$1,123
Fri 5/3110:19 amDFW - BHX
2 stops24h 56mUnited Airlines
Sun 6/25:55 amBHX - DFW
2 stops24h 00mUnited Airlines
Deal found 5/27$1,124
Wed 6/123:45 pmDFW - BHX
1 stop11h 50mDelta
Sun 6/166:15 amBHX - DFW
2 stops16h 37mDelta
Deal found 5/28$1,128
Sun 6/29:20 amIAH - BHX
1 stop17h 35mMultiple Airlines
Wed 6/127:45 amBHX - IAH
2 stops28h 17mMultiple Airlines
Deal found 5/28$1,130

Texas to Birmingham 2024 flight deals

Discover exclusive flight deals for travel between Texas and Birmingham in 2024. Find excellent offers based on user searches. Over the last 7 days, Cheapflights users made 2,696,634 searches. Data last updated May 28, 2024.
Scroll through some of the best deals on flights from Texas to Birmingham in 2024. Check back in a little while for more flight options.
Thu 10/37:20 amIAH - BHX
2 stops19h 10mAir Canada
Tue 10/89:10 amBHX - IAH
2 stops32h 11mAir Canada
Deal found 5/27$656
Sat 10/51:30 pmIAH - BHX
2 stops22h 40mMultiple Airlines
Tue 10/89:10 amBHX - IAH
2 stops32h 11mMultiple Airlines
Deal found 5/28$684
Sat 10/510:04 amIAH - BHX
2 stops16h 26mAir Canada
Tue 10/85:55 amBHX - IAH
2 stops35h 26mAir Canada
Deal found 5/27$686
Fri 10/43:50 pmIAH - BHX
1 stop18h 55mDelta
Tue 10/86:15 amBHX - IAH
1 stop13h 20mDelta
Deal found 5/28$714
Fri 10/411:30 amIAH - BHX
2 stops16h 05mDelta
Tue 10/86:15 amBHX - IAH
1 stop13h 20mDelta
Deal found 5/28$718
Fri 10/411:30 amIAH - BHX
2 stops16h 05mDelta
Tue 10/810:30 amBHX - IAH
2 stops19h 29mDelta
Deal found 5/28$728
Thu 7/183:45 pmDFW - BHX
1 stop11h 50mAir France
Fri 1/106:00 amBHX - DFW
1 stop13h 45mAir France
Deal found 5/28$737
Mon 9/93:45 pmDFW - BHX
1 stop19h 00mDelta
Fri 1/316:00 amBHX - DFW
1 stop13h 45mDelta
Deal found 5/28$738
Sun 9/83:23 pmDFW - BHX
2 stops15h 42mDelta
Fri 1/316:00 amBHX - DFW
1 stop13h 45mDelta
Deal found 5/28$742

Texas to Birmingham flights leaving soon

Find last-minute flight options from Texas to Birmingham 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 2,696,634 searches. Data last updated May 28, 2024.
Have a look at some of the flights available from Texas to Birmingham departing last-minute. Tip: verify your flight details before completing your reservation.
Sun 6/212:15 pmIAH - BHX
2 stops23h 45mMultiple Airlines
Wed 6/125:40 pmBHX - IAH
3 stops25h 55mMultiple Airlines
Deal found 5/28$1,090
Sun 6/29:20 amIAH - BHX
1 stop17h 35mMultiple Airlines
Wed 6/127:45 amBHX - IAH
2 stops28h 17mMultiple Airlines
Deal found 5/28$1,130
Sun 6/26:10 amIAH - BHX
3 stops32h 10mMultiple Airlines
Wed 6/128:15 amBHX - IAH
3 stops22h 24mMultiple Airlines
Deal found 5/28$1,293
Sun 6/28:30 amIAH - BHX
2 stops17h 50mMultiple Airlines
Wed 6/129:00 amBHX - IAH
2 stops18h 31mMultiple Airlines
Deal found 5/28$1,347
Sun 6/28:27 pmHOU - BHX
2 stops42h 03mBritish Airways
Wed 6/128:15 amBHX - HOU
2 stops19h 59mBritish Airways
Deal found 5/28$1,582
Sun 6/26:25 pmIAH - BHX
1 stop17h 00mUnited Airlines
Wed 6/125:55 amBHX - IAH
1 stop13h 40mUnited Airlines
Deal found 5/28$1,649

One-way flights to Birmingham from Texas

Search for one-way flight options from Texas to Birmingham. 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 2,696,634 searches. Data last updated May 28, 2024.
Users in need of a one-way flight from Texas to Birmingham can choose from these deals. For those needing a return trip from Texas, there is a search form available above.
Thu 9/125:38 amDFW - BHX
2 stops43h 57mMultiple Airlines
Deal found 5/28$247
Fri 9/64:30 pmDFW - BHX
2 stops24h 40mMultiple Airlines
Deal found 5/28$278
Sat 9/74:30 pmDFW - BHX
2 stops20h 30mMultiple Airlines
Deal found 5/28$288
Tue 7/167:23 pmDFW - BHX
3 stops42h 57mMultiple Airlines
Deal found 5/28$294
Tue 9/1010:16 amDFW - BHX
3 stops28h 04mMultiple Airlines
Deal found 5/28$296
Wed 9/118:16 amDFW - BHX
3 stops30h 09mMultiple Airlines
Deal found 5/28$300
Wed 9/114:30 pmDFW - BHX
2 stops23h 20mMultiple Airlines
Deal found 5/28$309
Mon 9/95:38 amDFW - BHX
2 stops29h 12mMultiple Airlines
Deal found 5/28$321
Mon 9/94:30 pmDFW - BHX
3 stops22h 50mMultiple Airlines
Deal found 5/28$331

Find flights from Texas to Birmingham within your budget

Customize your flight search to find flights from Texas to Birmingham 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 2,696,634 searches. Data last updated May 28, 2024.

Fly from

Any airport

Fly to

Any airport

Budget

$656 - $1,142

Route

Depart

Return

Price

Houston George Bush IntcntlBirmingham

IAH - BHX

IAHBHX

Houston George Bush Intcntl

Thu 10/3

2 stops19h 10m

Birmingham

Tue 10/8

2 stops32h 11m

$656

Houston George Bush IntcntlBirmingham

IAH - BHX

IAHBHX

Houston George Bush Intcntl

Sat 10/5

2 stops22h 40m

Birmingham

Tue 10/8

2 stops32h 11m

$684

Houston George Bush IntcntlBirmingham

IAH - BHX

IAHBHX

Houston George Bush Intcntl

Fri 10/4

1 stop18h 55m

Birmingham

Tue 10/8

1 stop13h 20m

$714

Dallas/Fort WorthBirmingham

DFW - BHX

DFWBHX

Dallas/Fort Worth

Thu 7/18

1 stop11h 50m

Birmingham

Fri 1/10

1 stop13h 45m

$737

Austin BergstromBirmingham

AUS - BHX

AUSBHX

Austin Bergstrom

Tue 7/30

2 stops17h 29m

Birmingham

Wed 8/7

2 stops20h 45m

$832

Dallas/Fort WorthBirmingham

DFW - BHX

DFWBHX

Dallas/Fort Worth

Mon 9/9

1 stop19h 35m

Birmingham

Wed 1/29

1 stop31h 20m

$866

Dallas/Fort WorthBirmingham

DFW - BHX

DFWBHX

Dallas/Fort Worth

Mon 7/8

2 stops15h 51m

Birmingham

Fri 12/6

3 stops42h 51m

$882

Dallas/Fort WorthBirmingham

DFW - BHX

DFWBHX

Dallas/Fort Worth

Fri 9/27

1 stop15h 20m

Birmingham

Sun 9/29

1 stop25h 20m

$984

Dallas/Fort WorthBirmingham

DFW - BHX

DFWBHX

Dallas/Fort Worth

Tue 9/10

1 stop37h 35m

Birmingham

Wed 1/29

1 stop37h 45m

$1,142

Flights are sorted by cheapest first

Deals found on 5/27

No data available for this route at this time. Please check back soon.

Best time to book a flight from Texas to Birmingham

Have a flexible travel schedule? Discover the best time to fly to Birmingham from Texas 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.

Reviews of airlines servicing Birmingham

Get insights into the airlines that provide service to Birmingham. 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 Birmingham. Reviews last updated May 28, 2024.
Read reviews from past customers who have flown Air France, Delta and United Airlines from Texas to Birmingham. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
8.0
Very good
10,476 reviews

Boarding

8.2

Crew

8.6

Overall

8.0

Food

7.4

Entertainment

8.0

Comfort

7.9

Reviews

1 / 10

Bad experience with the staff boarding the gate. I couldn’t board with my carry on, personal item and a funny bag. I had to put my passport inside my pockets and put the funny bag inside the personal item. Then after passing the staff pull out everything again.

8.0
Very good
10,476 reviews
8.0
Very good
10,476 reviews

Boarding

8.2

Crew

8.6

Overall

8.0

Food

7.4

Entertainment

8.0

Comfort

7.9

Reviews

1 / 10

Bad experience with the staff boarding the gate. I couldn’t board with my carry on, personal item and a funny bag. I had to put my passport inside my pockets and put the funny bag inside the personal item. Then after passing the staff pull out everything again.

7.9
Good
1,528 reviews
8.0
Very good
10,476 reviews

Boarding

8.2

Crew

8.6

Overall

8.0

Food

7.4

Entertainment

8.0

Comfort

7.9

Reviews

1 / 10

Bad experience with the staff boarding the gate. I couldn’t board with my carry on, personal item and a funny bag. I had to put my passport inside my pockets and put the funny bag inside the personal item. Then after passing the staff pull out everything again.

7.5
Good
1,736 reviews
8.0
Very good
10,476 reviews

Boarding

8.2

Crew

8.6

Overall

8.0

Food

7.4

Entertainment

8.0

Comfort

7.9

Reviews

1 / 10

Bad experience with the staff boarding the gate. I couldn’t board with my carry on, personal item and a funny bag. I had to put my passport inside my pockets and put the funny bag inside the personal item. Then after passing the staff pull out everything again.

7.4
Good
3,715 reviews
8.0
Very good
10,476 reviews

Boarding

8.2

Crew

8.6

Overall

8.0

Food

7.4

Entertainment

8.0

Comfort

7.9

Reviews

1 / 10

Bad experience with the staff boarding the gate. I couldn’t board with my carry on, personal item and a funny bag. I had to put my passport inside my pockets and put the funny bag inside the personal item. Then after passing the staff pull out everything again.

7.4
Good
10,799 reviews
8.0
Very good
10,476 reviews

Boarding

8.2

Crew

8.6

Overall

8.0

Food

7.4

Entertainment

8.0

Comfort

7.9

Reviews

1 / 10

Bad experience with the staff boarding the gate. I couldn’t board with my carry on, personal item and a funny bag. I had to put my passport inside my pockets and put the funny bag inside the personal item. Then after passing the staff pull out everything again.

Related info for your journey

Find useful and relevant information for your journey from Texas to Birmingham. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
  • What airport do you fly into for flights to Birmingham from Texas?

    Located just 6.8 mi from the city center, Birmingham (BHX) is the airport most travelers will use when flying to Birmingham from Texas.

  • Can I find flights from Texas to Birmingham for under $700 on Cheapflights?

    Yes, there are multiple flights from Texas to Birmingham for under $700. The cheapest flight booked recently is on Air Canada for just $656, but on average you can expect to pay $735.

  • Are there last-minute flights available from Texas to Birmingham for under $1,100?

    There are currently 6+ open flights from Texas to Birmingham within the next 7 days for less than $1,100.

  • What are the cheapest airlines to fly from Texas to Birmingham one-way?

    For one-way options, check prices for American Airlines. According to our data, you can fly for as low as $606. Users have also found prices from $642 and $687 on Air France and United Airlines, respectively.

  • What are the most popular routes from Texas to Birmingham?

  • What does DFW to BHX mean?

    DFW and BHX are unique codes to identify airports used in the aviation industry. They are defined by IATA (International Air Transport Association) and are commonly called IATA codes. DFW to BHX refers to a flight route from Dallas/Fort Worth Airport to Birmingham Airport. Ready for more IATA code knowledge? These are related airports for your current travel destination: Houston George Bush Intcntl Airport (IAH), Austin Bergstrom Airport (AUS), Houston Hobby Airport (HOU), San Antonio Airport (SAT), El Paso Airport (ELP).

  • Can I find deals for flights from Texas to Birmingham that include extra baggage allowance?

    The amount of baggage you can bring on your Texas to Birmingham 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 Texas to Birmingham with specific airlines?

    Yes, Cheapflights allows you to browse and filter Texas to Birmingham 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 Texas to Birmingham that include hotel bookings?

    Yes. In addition to deals on Texas to Birmingham flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Texas to Birmingham?

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

  • Can I find deals for business class flights from Texas to Birmingham?

    Yes. Cheapflights offers flight deals from Texas to Birmingham 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 Texas to Birmingham that allow pets onboard?

    Many airlines flying from Texas to Birmingham 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 Texas to Birmingham?

    Yes, you can often find last-minute deals on Texas to Birmingham 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 Texas to Birmingham flight deals updated?

    The Texas to Birmingham flight deals you see on this page were last updated on 5/28.

  • What are the most popular airlines that fly from Texas to Birmingham?

  • When is the best time to book a flight from Texas to Birmingham?

    Currently, November is the cheapest month in which you can book a flight from Texas to Birmingham (average of $613). Flying from Texas to Birmingham in June is currently the most expensive (average of $1,286). 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.

Alternative routes for Texas to Birmingham
See prices for flight routes from nearby airports that may be better suited for you.

Top 7 airlines flying from Texas to Birmingham

Discover the top 7 airlines that operate flights from Texas to Birmingham. 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 2,696,634 searches. Data last updated May 28, 2024.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$572Average$974FlexibilityNo cancel feeOn-timeN/A
Search Delta flights
Air FranceCheapest$589Average$1,032FlexibilityNo cancel feeOn-time77%
Search Air France flights
LufthansaCheapest$592Average$1,311FlexibilityNo cancel feeOn-time76%
Search Lufthansa flights
KLMCheapest$605Average$940FlexibilityNo cancel feeOn-time75%
Search KLM flights
United AirlinesCheapest$775Average$1,258FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
British AirwaysCheapest$806Average$1,198FlexibilityNo cancel feeOn-time70%
Search British Airways flights
American AirlinesCheapest$853Average$1,014FlexibilityNo cancel feeOn-time71%
Search American Airlines flights

Search flights from Texas to Birmingham by cabin class

Find flights from Texas to Birmingham, based on your preferred cabin class, be it economy, premium economy, business, or first class.

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travelers can enjoy low prices and a wide availability of flights to their desired destinations.

How does Cheapflights help users find flights from Texas to Birmingham?

Cheapflights helps you search for flights from Texas to Birmingham via 900+ travel sites so you don’t have to. After performing a flight search, users can also filter their flight selection by filtering for price, number of stops, airlines, and so on.

Why should you use Cheapflights to find cheap flight tickets from Texas to Birmingham?

By finding flights from multiple airlines and providers at completely no cost, Cheapflights helps millions of users like you annually find the best flights to Birmingham from Texas.

Can Cheapflights find flights from Texas to Birmingham with no change fees?

Need flexible booking options for your flight to Birmingham from Texas? Don’t worry, Cheapflights have you covered. Use our search filter to only show flights with no change fees.

Can Cheapflights notify me if prices for flights from Texas to Birmingham become cheaper?

Of course! You can now track prices for flights from Texas to Birmingham and get an alert from Cheapflights when they change. Have a valid email address ready and click the bell icon next to the flight deals above to set up your price alerts.

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.